WEBVTT 00:00:02.000 --> 00:00:20.000 We'll get some of Thunderstruck on there. 00:00:20.000 --> 00:00:27.000 I, uh, heard that Christy Rose… oh, she's in, nevermind. 00:00:27.000 --> 00:00:28.000 Thanks, Tyler. 00:00:28.000 --> 00:00:41.000 Fletcher's in the waiting room. 00:00:41.000 --> 00:00:44.000 Alright, sir, are you ready to take us out of here? 00:00:44.000 --> 00:00:49.000 Let's do this! 00:00:49.000 --> 00:01:03.000 Okay, welcome back, everyone! It's Thunder Talk time, and the great thing is, we got a record number of ThunderTalk submissions this year. The bad part is, we got a record number of ThunderTalk submissions, so we gotta get going. 3 minutes each. 00:01:03.000 --> 00:01:04.000 Thanks, Sarah, and you said exactly what I was gonna say? 00:01:04.000 --> 00:01:07.000 Grace, take us away! 00:01:07.000 --> 00:01:13.000 Talks will be 3 minutes, followed by a transition slide, and then the next speaker will jump right in. 00:01:13.000 --> 00:01:21.000 We're hoping to have a few minutes for Q&A at the end of this session, but we might not have enough time, so I encourage you to keep 00:01:21.000 --> 00:01:24.000 using the chat function for your comments and questions. 00:01:24.000 --> 00:01:31.000 And with that, I'll turn it over to John and our first speaker, Scott Marshall. 00:01:31.000 --> 00:01:33.000 Okay, so I guess I should go. 00:01:33.000 --> 00:01:44.000 Okay, alright, my name is Scott Marshall, and I'm very excited to tell you today about our new Community Velocity Model Explorer. These are a series of web-based tools to make working with velocity models easier. 00:01:44.000 --> 00:01:50.000 I posted, uh, links in the chat for you in case you can't read the bottom left hand of the screen. 00:01:50.000 --> 00:01:57.000 So, if you go to the community velocity Model Explorer, you'll see a page that looks very similar to our other community explorers at SCEC. 00:01:57.000 --> 00:02:00.000 At the top, there is a link 00:02:00.000 --> 00:02:05.000 There are buttons to choose your basemap, and you can upload your own data files to compare. 00:02:05.000 --> 00:02:11.000 But on the left over here, you'll see that there are buttons that allow you to check… uh-oh, somebody else has changed my slide. 00:02:11.000 --> 00:02:21.000 Um, there are buttons that allow you to check which model you want, and what kind of profile you want to create, so what I've done here is I've created the CyberShake 248 model. 00:02:21.000 --> 00:02:24.000 And we're gonna take a two-dimensional horizontal slice through it. 00:02:24.000 --> 00:02:27.000 So if you click on the next button, 00:02:27.000 --> 00:02:34.000 you should be given a box. You can either put in the latitudes and longitudes by hand, or you can click and drag on the map. 00:02:34.000 --> 00:02:44.000 Once you do that, you'll be treated with a window that tells you that the data that you're extracting is going to be interpolated, it's not directly from the model. That allows us to make plots that have a consistent style and 00:02:44.000 --> 00:02:49.000 quality. Then, it takes about 20 to 30 seconds to extract from most models. 00:02:49.000 --> 00:02:56.000 Once you get it, you'll see down at the bottom here, there's an option to download the data in CSV format, or to plot the data. 00:02:56.000 --> 00:03:01.000 And so you can do whatever you want with the CSV files, um, but the plotting interface was a fun part of this to code up for me. 00:03:01.000 --> 00:03:08.000 And it uses the open source generic mapping tools package, and this is a view of that CyberShake model. You'll see there's kind of… 00:03:08.000 --> 00:03:11.000 artifacts on the right, that's because this is a tiled model. 00:03:11.000 --> 00:03:16.000 But the cool thing is, what if you want to plot some cities, or some… the community fault model faults? 00:03:16.000 --> 00:03:20.000 There are options over here on the top left that will allow you to do that. 00:03:20.000 --> 00:03:27.000 And then all you have to do is select Replot, and within about 3 seconds, your plot will be regenerated. 00:03:27.000 --> 00:03:35.000 Um, you can also interpolate the model if you want to smooth it. It uses splines and tension, which might not be appropriate for all uses, but if you do, it's there. 00:03:35.000 --> 00:03:40.000 Um, so if I click Replot, it'll smooth out my plot very nicely. 00:03:40.000 --> 00:03:49.000 The nice thing is you can also replot VS, VP, or density without having to re-extract, and you can change the color map. We have 3 color maps available. 00:03:49.000 --> 00:03:56.000 So, what we're looking at right now is density over using a perceptually uniform color map called Plasma. 00:03:56.000 --> 00:04:05.000 You can also force the color map ranges if you want to compare different plots to each other, and once you're done, the most important thing is that you get a plot that you can use. 00:04:05.000 --> 00:04:11.000 So, this is the actual pot that was generated. It's high-quality PNG, or vectorized PDFs. 00:04:11.000 --> 00:04:16.000 So, once you get this stuff, you're good to go, and you can use it for whatever you want. The nice thing is, if you forget… 00:04:16.000 --> 00:04:19.000 Where you've, um, come from? 00:04:19.000 --> 00:04:25.000 You can regenerate these pots with the information in the titles, so that's why we have those long titles there. 00:04:25.000 --> 00:04:33.000 The interface can also make two-dimensional vertical profiles and one-dimensional, uh, vertical profiles, and also you can upload random XYZ files. 00:04:33.000 --> 00:04:56.000 So we hope this is useful, and if you have any questions or comments, put them in the chat, or let me know. Thanks! 00:04:56.000 --> 00:05:01.000 Good afternoon, everyone. It's my pleasure to be here, and great thanks for tuning in. 00:05:01.000 --> 00:05:07.000 My name is Aparna, I'm from Texas Tech, and here I would like to describe my PhD research related to. 00:05:07.000 --> 00:05:14.000 In SAR observations of circuit deformation over the Geyser's geothermal fields in Northern California. 00:05:14.000 --> 00:05:24.000 Uh, the guys' geothermal feel is not only the largest geothermal field in California, but also the largest in the nation in terms of. 00:05:24.000 --> 00:05:35.000 energy production. It averagely produces about 6.5 billion kilowatt hours per year for the nearby communities of Northern California. 00:05:35.000 --> 00:05:39.000 Since 1960, which is about 60 years of production. 00:05:39.000 --> 00:05:44.000 It's one of the largest dry steamed geothermal field in the world, meaning that. 00:05:44.000 --> 00:05:50.000 Underground, he produces team directly, rather than hot water, to power up the turbine. 00:05:50.000 --> 00:06:03.000 Um, the production area is mainly located in the Mycamas Mountain, north of San Francisco, California, surrounded by a complex fault systems, including from the south, the San Andres Fault. 00:06:03.000 --> 00:06:10.000 The northern Rogers Creek Fall, the Makama Falls. Uh, the Bartlett Springs Falls, Kolayama Fault. 00:06:10.000 --> 00:06:16.000 The black dots here shows the seismicity since 1967. 00:06:16.000 --> 00:06:23.000 unevenly clustering along those falls, and particularly over the geyser's geothermal wells. 00:06:23.000 --> 00:06:30.000 Near the producing power plant, there are altogether 5 94 production belts. 00:06:30.000 --> 00:06:41.000 Uh, producing about 3, 14 barrels, megabarrels per year of steam, and 156 injection wells, uh, with one… about 150 megabarrels of condensed water. 00:06:41.000 --> 00:06:46.000 Giving rise to a net production of about 150 megabarrels per year. 00:06:46.000 --> 00:06:51.000 Um, as such, since 1960, when the power plant was. 00:06:51.000 --> 00:07:00.000 First loan, billions of barrels of steams have been removed from underground. This is consistent with our INSAR observations from 2017 to. 00:07:00.000 --> 00:07:06.000 2025, and here is the insert data of Sentinel-1, um, ascending. 00:07:06.000 --> 00:07:18.000 line of sight, the subsidence spans over geysersfield, and it forms a northwest-southeast trenching subsidence lobe of an area greater than 60 kilometers square. 00:07:18.000 --> 00:07:28.000 Covering those production and injection bills. The red and the dark red regions denote areas of subsidence greater than 10 mm per year. 00:07:28.000 --> 00:07:37.000 And this subsidence rate is comparable to another California geothermal field, the Corso, but the former subsiding area is double. 00:07:37.000 --> 00:07:42.000 As such, we are planning to use thermopore elastic model to inboard the performance data. 00:07:42.000 --> 00:07:47.000 And to assimilate the stress and the poor pressure changes of grades or visor and. 00:07:47.000 --> 00:07:55.000 Evaluate how these changes. Could be related to the nearby falls activities and the seismicity distribution. 00:07:55.000 --> 00:08:07.000 Thank you. 00:08:07.000 --> 00:08:12.000 Hi, I'm Andrea Donilan. I'm at Purdue, I was at JPL prior to that. 00:08:12.000 --> 00:08:22.000 I'll be mostly giving an informational talk about applying topography and deformation to understanding Northern California earthquakes. I couldn't easily talk about the science and the infrastructure that we're 00:08:22.000 --> 00:08:29.000 standing up through NASA. I lead a study called Surface Topography and Deformation for NASA to plan on a mission in the next 00:08:29.000 --> 00:08:33.000 10 years for launch, and probably a disaggregated 00:08:33.000 --> 00:08:39.000 configuration like we see here, sometime by about 2035. 00:08:39.000 --> 00:08:48.000 There we go. The surface topography and Vegetation Study addresses the four spheres of NASA that they've defined now. 00:08:48.000 --> 00:08:56.000 or are… have adopted. We look at how does Earth changing surface structure inform us about natural hazards, vegetation, and water resources. 00:08:56.000 --> 00:09:03.000 The one relevant to us in Northern California earthquakes is Geosphere. How does Earth's surface respond to tectonic and geomorphic 00:09:03.000 --> 00:09:11.000 processes, and a goal of the project is to produce bare earth topography and separate out vegetation structure. 00:09:11.000 --> 00:09:13.000 From that… 00:09:13.000 --> 00:09:24.000 That's then useful in identifying geophysical processes. I think most of the audience here understands that. This is a LiDAR map on the left of Incline Village and Lake. 00:09:24.000 --> 00:09:28.000 On the left panel, we have the built environment, as well as the vegetation. 00:09:28.000 --> 00:09:38.000 Ramon Aerosmith removed all of that. On the right panel, then the incline village faults shows up very nicely. So STV will be a great way to get a synoptic view. 00:09:38.000 --> 00:09:42.000 of regional tectonics and fault activity. 00:09:42.000 --> 00:09:49.000 This is a picture of us at our STV, one of our STV meetings out on the Incline Village Fault. That's Bill Hammond in the front there. 00:09:49.000 --> 00:10:00.000 Um, you can see that it's a general rise, that fence is there, to fence off an elementary school that's been closed because of the fault, but it's much easier to step back and see it from. 00:10:00.000 --> 00:10:02.000 LiDAR or from space. 00:10:02.000 --> 00:10:06.000 from either LiDAR or stereo imaging. 00:10:06.000 --> 00:10:07.000 We used UAV SAR, 00:10:07.000 --> 00:10:09.000 To measure… 00:10:09.000 --> 00:10:11.000 I'll just move this, sorry. 00:10:11.000 --> 00:10:16.000 To measure the Napa earthquake, which is an airborne radar instrument, and one of the instru… 00:10:16.000 --> 00:10:22.000 things that came out of his paper, which we did with Steve DeLong, who I believe is going to be speaking soon in this session. 00:10:22.000 --> 00:10:29.000 is that the rupture did not occur on the main map trace of the fall. It did occur where there was a topographic bench, 00:10:29.000 --> 00:10:35.000 Which makes an argument for blending the topography as well as the, um… 00:10:35.000 --> 00:10:38.000 As well as the deformation on the… on the right, you can see the 00:10:38.000 --> 00:10:41.000 co-seismic motion occurred the same. 00:10:41.000 --> 00:10:48.000 This is just a quick advertise for… an advertisement for a Quakeside instrument that we have to do stereo imaging. 00:10:48.000 --> 00:10:57.000 This is an example of the Alumni rock earthquake. We flew before the earthquake, one day before, and right after the earthquake, within about an hour. 00:10:57.000 --> 00:11:02.000 This is our flight lines, if anybody wants data. We have it, we can provide it to you. 00:11:02.000 --> 00:11:31.000 And then we have an airborne campaign coming up this summer to combine radar, LIDAR, and stereo imaging to start… do a Pathfinder for this mission. Oh, and I should mention that NYSAR just launched, and is almost operational. 00:11:31.000 --> 00:11:37.000 Hello, um, good afternoon. So, um, very interesting talk, thanks, Andrea. 00:11:37.000 --> 00:11:44.000 Um, the… I'm going to talk about triggered slip, which we've known about since 1966. 00:11:44.000 --> 00:11:53.000 But it's always been a little bit puzzling, whether it's something going wrong with the instrument, or whether the fault actually slipped. Well, we know the fault slips, but at some level, 00:11:53.000 --> 00:11:55.000 We don't know why and how. 00:11:55.000 --> 00:12:01.000 So, I'm going to just give you a couple of insights we've got from recent, um, 00:12:01.000 --> 00:12:11.000 measurements. An example of triggered slip is shown on the right. You see the top right-hand panel, does this thing work? I don't know. The top right-hand panel shows 00:12:11.000 --> 00:12:21.000 Um, black dots. That's typical 10-minute sampling in most of the creep data that's been acquired in the last five decades. 00:12:21.000 --> 00:12:27.000 The red line shows what we've been getting recently from one-minute samples, and the bottom line shows 00:12:27.000 --> 00:12:30.000 Last year's Mendocino earthquake, 00:12:30.000 --> 00:12:35.000 Um, which we… we, uh, recorded at 1Hz. 00:12:35.000 --> 00:12:41.000 sampling frequency. And what you can see rather clearly is that triggered slip occurs during the passage of 00:12:41.000 --> 00:12:47.000 surface waves. So that's a sort of insights we're getting from recent data that 00:12:47.000 --> 00:12:51.000 Um, kind of puts a lot of pieces of the puzzle together. 00:12:51.000 --> 00:12:53.000 Um, so… 00:12:53.000 --> 00:12:55.000 In the next slide, I show 00:12:55.000 --> 00:12:57.000 Um, 00:12:57.000 --> 00:13:00.000 a picture of a creeping fort. 00:13:00.000 --> 00:13:06.000 Along the lines of what we found for the Napa Fort Josie Nevitz, uh, 00:13:06.000 --> 00:13:11.000 discoveries about surface slip being, um, impeded by, uh, stiff 00:13:11.000 --> 00:13:15.000 carapace above a deeper creeping zone. 00:13:15.000 --> 00:13:19.000 Now, on the right, you can see after-slip from 00:13:19.000 --> 00:13:25.000 a… an earthquake on the East Anatolian Fort, the Sivrice earthquake in 2020, 00:13:25.000 --> 00:13:28.000 Uh, the top… sorry, the bottom, uh, 00:13:28.000 --> 00:13:30.000 panel shows 00:13:30.000 --> 00:13:32.000 Typical after-slip decay curve. 00:13:32.000 --> 00:13:38.000 And there's a close-up it, close-up of it, shown in the top slide. 00:13:38.000 --> 00:13:40.000 And in that, you can see about 00:13:40.000 --> 00:13:45.000 10 or 10 to 15 aftershocks, each which produces slip. 00:13:45.000 --> 00:13:49.000 Now, what we found, interestingly, is that 00:13:49.000 --> 00:13:53.000 Uh, slip is not just triggered by shaking, but it's also triggered by 00:13:53.000 --> 00:14:03.000 Um, changes in atmospheric pressure and rainfall. And here are two examples, one for the North Anatolian port, one for the Calaveras Fort. They show the rainfall in blue, 00:14:03.000 --> 00:14:09.000 Red is the slip. In each case, about 7 millimeters. My point is that slip occurs 00:14:09.000 --> 00:14:17.000 Both through dynamic processes and by Coulomb failure processes associated with wettening of that. 00:14:17.000 --> 00:14:22.000 up a stiff carapace. 00:14:22.000 --> 00:14:33.000 Thanks. 00:14:33.000 --> 00:14:41.000 All right, hi there. I want to give you an update on the status of Fault Creek monitoring using the Alignment Array Network in Northern California. 00:14:41.000 --> 00:14:51.000 The, uh, update is the alignment arrays are no longer being measured, but this talk is actually an introduction to the next talk where we can address that a little bit more. 00:14:51.000 --> 00:14:59.000 So what is the alignment array project? This has, uh, been a cooperative project in the USGS and San Francisco State for, um. 00:14:59.000 --> 00:15:22.000 a number of years, and uh… if you see the inset photo there, the air photo of survey monuments are placed across fault zones that are suspected of creeping. Uh, instrument is placed on the marker that ends in I, and an angle is measured parallel to the fault to an offset marker ends in O, and then an angle is measured across the fall to the end station, and as fault creep proceeds. 00:15:22.000 --> 00:15:29.000 that angle will change, and these angles can be converted to actual measurements of distance and creep rates. Uh, this is. 00:15:29.000 --> 00:15:38.000 Currently inactive. I think lots of people have worked on this project over the years. The two people in the time I've been at USGS who have been… who really drove out were Jim Leincamper. 00:15:38.000 --> 00:15:54.000 And, uh, Forrest McFarlane at San Francisco State, so we all owe them a debt of gratitude for their dedication to this project for many, many years. Uh, currently we don't have the staffing to have an obvious way forward. If you look at the map on the right, you'll see that there's a number of arrays on the creeping faults of Northern California. 00:15:54.000 --> 00:16:05.000 Uh, these are all north of the San Andreas Fall creeping section. 60 of these can be considered active, 15 are probably destroyed and inactive, and 15 have unknown status. 00:16:05.000 --> 00:16:15.000 And you can see a few things, like the very dense array of these alignment arrays along the Hayward Fault in the East Bay, and more sparse measurements elsewhere where access. 00:16:15.000 --> 00:16:22.000 is more challenging. It does also include the after-slip measurements and NAPA. 00:16:22.000 --> 00:16:48.000 Uh, just to describe the data set a bit more, uh… these have been… many of these were established in the 19… as early as the 1960s or 70s, uh, and have been established consistently over the recent decades. Most of them were measured consistently up until 2010's 2020, so it's a fairly complete data set, long-term monitoring. And, uh, some of these arrays have over 60 years of measurement. You can see in the lower left the elapsed years of measurement there. 00:16:48.000 --> 00:17:04.000 And these represent the creeping faults of the Bay Area, so the creep rates are not as high as the creeping San Andreas, but there are creep rates between 0 and 16 millimeters a year. 16 is probably the northern end of the… San Andreas. 00:17:04.000 --> 00:17:12.000 Um, so all the data up through the last survey, which was conducted in early 2025, are available as a USGS data release. This was published. 00:17:12.000 --> 00:17:22.000 Uh, over our lunch break, actually, hopefully the QR code will work. Uh, this release is, uh, a slightly updated, um, machine-readable, and a simplified version. 00:17:22.000 --> 00:17:31.000 of the data from before, but all previous data releases and open file reports and several journal articles are linked from this data release, so if you want to learn more about this dataset, you can. 00:17:31.000 --> 00:17:39.000 go there, have a look at the data, and also look at the previous publications by SF State and USGS. 00:17:39.000 --> 00:17:42.000 Thanks. 00:17:42.000 --> 00:17:46.000 Thank you so much, Steve, and everyone at the USGS who has been 00:17:46.000 --> 00:17:54.000 Um, contributing to this in the SF State crew and everything. Um, so I… with Betsy Madden, we put in this proposal to SCEC, 00:17:54.000 --> 00:17:56.000 Um, during the government shutdown, of course, 00:17:56.000 --> 00:18:03.000 to host a workshop to address the problem that Steve just outlined, is that we have a loss of some institutional knowledge, and… 00:18:03.000 --> 00:18:14.000 Also, a loss of some institutional passion that have been keeping the alignment array, uh, measurements alive for a long time. Um, this is not 00:18:14.000 --> 00:18:20.000 a effort that I have been part of in the past. My motivation for coming to this, and I may be speaking for Betsy too, 00:18:20.000 --> 00:18:34.000 It's just that we've always passionately appreciated having access to these data in a distributed, um, kind of spatial insights that it gives us across the Bay Area. So, Betsy and I are a little bit new to this, and um… 00:18:34.000 --> 00:18:41.000 We're really grateful to have everyone's support and coordination so that we can get people together to talk about what to do. 00:18:41.000 --> 00:18:51.000 So, the workshop, um, the registration has closed, but you can still probably hop on via Zoom for, um, the talks if you want to. 00:18:51.000 --> 00:19:00.000 Um, the questions that we're going to try to grapple with is, uh, how well can we try to maintain the status quo, which is regular measurements across the entire Lyman array as much as possible? 00:19:00.000 --> 00:19:07.000 Is it possible that this could be maintained by distributing the workload somewhat across a broader group of people? 00:19:07.000 --> 00:19:18.000 Um, initial reports from new experts indicate that making a measurement is not trivial. It's really high precision, there's finicky and specific equipment, and it might not be something where 00:19:18.000 --> 00:19:24.000 We… we may have to grapple with the trade-off between quantity and quality, um, in order to keep it alive. 00:19:24.000 --> 00:19:33.000 Um, we want to do a total review of the array sites, and maybe some prioritization, especially if we can't maintain that high quality across the entire geographic network. 00:19:33.000 --> 00:19:44.000 Um, and then there are so many other tools in Geodyssey and strain measurement, um, that we want to maybe try to define some community criteria of, like, where and when 00:19:44.000 --> 00:19:50.000 other data sets might supplant the nail arrays, and so that we could retire them gracefully with a… 00:19:50.000 --> 00:19:52.000 transition to another data set. 00:19:52.000 --> 00:20:00.000 Um, and that will involve unpacking the use cases, uh, how creep data is getting incorporated into seismic hazard estimation, the National Seismic Hazard Model, 00:20:00.000 --> 00:20:08.000 Um, how it goes into building codes, um, obviously looking at California specifically, but also more broadly about how these kind of data are treated. 00:20:08.000 --> 00:20:13.000 Elsewhere, uh, and… 00:20:13.000 --> 00:20:24.000 Yeah, um, so, well, one thing that we'll do in the workshop, we have a one-day field trip. We are going to visit alignment arrays, and we are going to look at other methods of creep measurement that are done in the field, so… 00:20:24.000 --> 00:20:27.000 Um, you know, with that type of spatial resolution, 00:20:27.000 --> 00:20:34.000 Um, and so here's an example of mobile lighter scanning that uses a broader area than three points. 00:20:34.000 --> 00:20:38.000 Um, but also can come up with a really similar result. 00:20:38.000 --> 00:20:47.000 Um, and also captures a little bit more of the off-vault deformation if we are concerned about the aperture of the installation, whether it's captured all of the active strands of the fault. 00:20:47.000 --> 00:20:52.000 Um, here's one example of that, uh, that I think we're gonna hear about from Tyler and maybe Kim later. 00:20:52.000 --> 00:21:02.000 We have the San Gregorio Fault at Pillar Point. Um, there were some known active strands that have been studied previously, and the alignment array was installed over that series of faults. 00:21:02.000 --> 00:21:09.000 Uh, but we also have recently discovered strands that were not encompassed in the alignment array, which are a little bit farther outside. 00:21:09.000 --> 00:21:15.000 Guess that's it, thank you. 00:21:15.000 --> 00:21:20.000 Hi everyone, my name is Emil, and I'm a high school senior at the College Preparatory School. 00:21:20.000 --> 00:21:25.000 Uh, first I'd like to give a huge thanks to Professor Roland Bergman for advising me through this project. 00:21:25.000 --> 00:21:30.000 My research focuses on the creeping section of the central San Andreas Fault. 00:21:30.000 --> 00:21:37.000 So I analyzed nearly 40 years of data from 4 long-running, uh, creep meters. San Juan Bautista, Harris Ranch, Sanago Winery, and Melendy Ranch. 00:21:37.000 --> 00:21:40.000 The right shows the long-term displacement of these stations. 00:21:40.000 --> 00:21:50.000 Uh, the small step-like jumps are creep events, and my goal is to identify systematic changes in creep rate around these events. 00:21:50.000 --> 00:21:56.000 Some experiments and models suggest interesting temporal patterns of both pre- and post-event rate accelerations. 00:21:56.000 --> 00:22:01.000 We aim to see if real-world data from creep meters reflects this. 00:22:01.000 --> 00:22:05.000 I include only creep events like the example on the left. 00:22:05.000 --> 00:22:09.000 With linear behavior before and after the event. So I can calculate robust creep rates. 00:22:09.000 --> 00:22:15.000 I exclude messy events like the one on the right, because the creep rate is clearly unstable. 00:22:15.000 --> 00:22:24.000 Um, some methods I use are an adaptive moving window and sigma clipping to determine the time period over which I can compute the pre- and post-creep rates. 00:22:24.000 --> 00:22:27.000 This stacked, normalized profile of 00:22:27.000 --> 00:22:33.000 clean Santa and Bautista events shows the remarkable similarity in the creep event shapes. 00:22:33.000 --> 00:22:38.000 In these plots, each panel shows a station. 00:22:38.000 --> 00:22:43.000 In which I compare the pre-event creep rate, shown on the x-axis, with the post-event creep rate shown on the y-axis. 00:22:43.000 --> 00:22:46.000 Take the upper left San Juan Bautista as an example. 00:22:46.000 --> 00:22:54.000 Uh, the majority of points lie above the Y equals X line, indicating that more events have higher post-event creep rates than pre-event creep rates. 00:22:54.000 --> 00:22:57.000 Depending on the station, about 50-70% of events 00:22:57.000 --> 00:23:00.000 show a positive post-minus-pre-change. 00:23:00.000 --> 00:23:02.000 There also appears to be a spatial trend. 00:23:02.000 --> 00:23:10.000 So at the most northwestern station, San Join Bautista, 69% of events show an increase in post-event rates. 00:23:10.000 --> 00:23:14.000 With a fraction decreasing to 53% towards the southeast. 00:23:14.000 --> 00:23:20.000 We also observe noticeable seasonal behavior. So in each panel, the red points indicate the dry sick summer months, 00:23:20.000 --> 00:23:22.000 In the blue, the rainy 6 months. 00:23:22.000 --> 00:23:33.000 For all stations except San Diego Winery, the red points tend to be displaced from the blue points along the diagonal line towards the upper right, indicating that both pre- and post-rates 00:23:33.000 --> 00:23:36.000 are higher in the dry season than in the wet season. 00:23:36.000 --> 00:23:50.000 However, for the points above and below the y equals X line, there's no noticeable difference between red and blue, indicating that the systematic increase in creep rates after the events has little seasonal dependence. 00:23:50.000 --> 00:23:56.000 To summarize, we find that, one, many creep events are followed by increased creep rates, independent of season, 00:23:56.000 --> 00:24:01.000 And two, that both pre- and post-event creep rates are higher during the dry season. 00:24:01.000 --> 00:24:07.000 These patterns point to changes in fold friction, fault heterogeneity, event propagation, and possibly poor pressure. 00:24:07.000 --> 00:24:14.000 Going forward, we can test these ideas using data from 20 additional sites across multiple folds to see if the patterns hold. 00:24:14.000 --> 00:24:29.000 Uh, thank you for listening, and if you have any questions or comments, please reach me at my email. 00:24:29.000 --> 00:24:37.000 All right, what an excellent talk to follow on. Um, so we're gonna hop down, uh, even further south, and also there. 00:24:37.000 --> 00:24:45.000 Uh, to the creeping central San Andreas Fault again, which is bounded by the 1906 and 1857 earthquake extents that remain locked today. 00:24:45.000 --> 00:24:52.000 Now, the central section, again, creeps at a rate of about 30 millimeters per year, estimated from both geodesy and geology. 00:24:52.000 --> 00:24:56.000 And creep has likely occurred for the last 2 million years. 00:24:56.000 --> 00:25:06.000 Suggesting over about 6 kilometers of offset has accrued, potentially without large magnitude earthquakes. It's an interesting phenomenon, to say in the least, and has left its mark on the landscape. 00:25:06.000 --> 00:25:11.000 Culturally, the effects of creep are observed in our infrastructure, such as roads, bridges. 00:25:11.000 --> 00:25:28.000 Uh, and old buildings. And geodetically, the fault has been monitored with alignment arrays since the late 1960s. This is an example of an array at Me Branch. Originally documented in a study by Burford and Harsh in 1980 is creeping at a rate of about 26 millimeters per year. 00:25:28.000 --> 00:25:39.000 Updated measurements using new methods, including remote sensing data, reveal little new information on the rate of slip, and it's pretty darned constant on the geologic to decadal timescale. 00:25:39.000 --> 00:25:50.000 So this makes the fault an amazing target for methods development, and also opens an opportunity to push the bounds of our understanding of near-fault surface complexity and evolution at finer scale. 00:25:50.000 --> 00:26:03.000 Accordingly, we aim to increase the spatial resolution of fault creep measurements through tracking offsets in repeat half-meter resolution LiDAR DEMs. For reference, the highest resolution map of Creep to date is about 40 meters. 00:26:03.000 --> 00:26:10.000 And for analyzing the fine-scale fault development in geometric complexity that's useful, but we can perhaps do even better. 00:26:10.000 --> 00:26:19.000 So we've updated our measurements for the repeat… with repeat LiDAR, um, and now have promising maps of half-meter resolution displacements near the fault. 00:26:19.000 --> 00:26:28.000 They highlight, uh, displacements that would be, um, subpixel and indistinguishable by eye on the map, but the method has its limitations and requires validation. 00:26:28.000 --> 00:26:38.000 So, alignment arrays can help to provide this validation. Here, the LIDAR results sampled across the fault at the location of Mew Ranch demonstrate that the LiDAR creep rates. 00:26:38.000 --> 00:26:47.000 Oh! lie within the uncertainty of updated AA measurements. 00:26:47.000 --> 00:26:58.000 I don't have control. Um… But basically, the gist is not a lot is new at large scale, and we can hop over to the last two slides. 00:26:58.000 --> 00:27:15.000 And just show two examples where there's, uh… high-resolution… Here we go. At the Mussing Ridge Stepover, we see abandoned map trans-tensional faults, um, and this is a possible development of a smaller scale, uh, pressure ridge. 00:27:15.000 --> 00:27:26.000 Um, and you can see that 30 meter scale bar down there. So we're excited for the, um, methodologic potential revealed through this study, as well as the ability to investigate. 00:27:26.000 --> 00:27:32.000 fine-scale fault processes that bridge part of the temporal gap and geomorphic to active geodetic timescales. 00:27:32.000 --> 00:27:36.000 Thank you. And thank you, John, that was great. 00:27:36.000 --> 00:27:45.000 Did some good clicking through. 00:27:45.000 --> 00:27:51.000 Hi everyone, I'm Belle Filibosian. I'm going to present some preliminary results from. 00:27:51.000 --> 00:27:57.000 trend study of the creeping San Andreas Fault at the Topo Creek site. 00:27:57.000 --> 00:28:05.000 So, as Cassie just described, the creeping section of the San Andreas Fault is about 150 kilometers long, creeping at rates that approach the long-term slip rate. 00:28:05.000 --> 00:28:13.000 Uh, determined by geodesy. There's no historical seismicity, uh, greater than magnitude 6 except at Parkfield in the southern end. 00:28:13.000 --> 00:28:18.000 Which leads to debate as to whether large seismic ruptures ever propagate through. 00:28:18.000 --> 00:28:23.000 in the National Seismic Hazard Model, large ruptures through this creeping section. 00:28:23.000 --> 00:28:31.000 are permitted about every 1,100 years, and many of these are extremely large ruptures above magnitude 8. 00:28:31.000 --> 00:28:37.000 Connecting northern and Southern California faults. Those are about every 1500 years. 00:28:37.000 --> 00:28:43.000 There is quite limited paleosemic and geologic data that can constrain. 00:28:43.000 --> 00:28:49.000 Um, the frequency of these ruptures. There are a few previous Stretch studies, but many are. 00:28:49.000 --> 00:29:00.000 either not completely published or not ideally located. We have investigated the new site, Topo Creek, which is near the center of the creeping section, which minimizes any input from the edges. 00:29:00.000 --> 00:29:09.000 of 1906 or 1857-like ruptures. This site has a high sedimentation rate, producing good stratigraphy capable of preserving paleoseismic features. 00:29:09.000 --> 00:29:17.000 And the fault of this location has a simple geometry with a single, fairly continuous, actively creeping strap. 00:29:17.000 --> 00:29:22.000 What we have found at the site is that we've investigated, uh. 00:29:22.000 --> 00:29:26.000 Three trenches crossing the fault, and most of the evidence that we've found is. 00:29:26.000 --> 00:29:33.000 consistent with or even requires a seismic creep. The fault zone is fairly narrow, about 10 meters wide. 00:29:33.000 --> 00:29:42.000 Most of which has this pervasive. Penetrative feathery sheer fabric without very many, uh, well-defined individual fault planes. 00:29:42.000 --> 00:29:51.000 The… rather than having, um… clearly defined upward terminations of faults, the offset and deformation gradually decrease upward. 00:29:51.000 --> 00:29:55.000 with small amounts of offset distributed over a broad zone. 00:29:55.000 --> 00:30:02.000 in, uh, trench 4 in the lower image, the fold… it's dominated by folding rather than faulting. 00:30:02.000 --> 00:30:05.000 With no large rupture at all in the upper section. 00:30:05.000 --> 00:30:11.000 Above the black line. We don't have dates for that yet, but those are pending. 00:30:11.000 --> 00:30:17.000 There is very limited evidence that could be consistent with large seismic ruptures. 00:30:17.000 --> 00:30:25.000 Um, there are no features indicative of sudden brittle rupture, such as broken blocks, filled fissures, gluial wedges, no liquefaction features. 00:30:25.000 --> 00:30:34.000 No distinct upward terminations of faults. And only one kind of moderately defined deformation contrast in T3, for which we don't know the age yet. 00:30:34.000 --> 00:30:39.000 The large offset is confined to a very narrow zone, only about 2 meters wide. 00:30:39.000 --> 00:30:47.000 We interpret that, um, no more than one large cocycemic surface rupture could have occurred within the last 2200 years. 00:30:47.000 --> 00:30:52.000 And none are required by the data that we see in these trenches. 00:30:52.000 --> 00:31:02.000 Thank you. 00:31:02.000 --> 00:31:11.000 Uh, hello. Uh… My name's Tyler Ludinski, I'm gonna be sharing some new paleoseismic observations of the San Gregoria Fault. 00:31:11.000 --> 00:31:20.000 from Pillar Point Bluff, near Half Moon Bay. Uh, primary collaborators, uh, the help of this project, Kim Bluzniak and Hudson Washburn from San Jose State. 00:31:20.000 --> 00:31:31.000 So, um, let's go ahead and just… dive into the results. So, Pillar Point Bluff is a distributed flower structure, offsetting stratified marine terrace deposits. 00:31:31.000 --> 00:31:37.000 Uh, the cap-in alluvial unit is offset discreetly by about 3.5 meters. 00:31:37.000 --> 00:31:42.000 And we have evidence for multiple earthquakes on east-dipping thresholds. 00:31:42.000 --> 00:31:48.000 Uh, the OSL ages, from the base of the Marine Terrace sands are consistently between. 00:31:48.000 --> 00:31:53.000 40 to 50,000 years old, which correlate well to MIS stage 3. 00:31:53.000 --> 00:32:02.000 Using those ages, um… You can produce, uh, estimated uplift rates that range between 1.9 and 2.4. 00:32:02.000 --> 00:32:13.000 Meters per thousand years. So, um… The point of this slide is to show that the San Gregorio Fault is primarily located offshore. 00:32:13.000 --> 00:32:17.000 Um, as shown in the, uh, mapping in the red. 00:32:17.000 --> 00:32:22.000 The red lines, and uh… the onshore mapping is shown in purple. 00:32:22.000 --> 00:32:26.000 The other takeaway from this slide is that it's a highly distributed fault system. 00:32:26.000 --> 00:32:29.000 Um, the other thing is that the slip rate. 00:32:29.000 --> 00:32:35.000 Uh, estimates range widely between 2.5 to 10 millimeters per year. 00:32:35.000 --> 00:32:38.000 So if we zoom in kind of near Half Moon Bay, Pillar Point. 00:32:38.000 --> 00:32:43.000 Uh, here we have the offshore bathymetry data and onshore LIDAR data. 00:32:43.000 --> 00:32:49.000 The red arrows are defining the prominent scarps along each. 00:32:49.000 --> 00:33:05.000 And if we highlight the orientation… Uh, of each… section, offshore… And onshore, these prominent scarps, we can see that there's a… about 10 degree. 00:33:05.000 --> 00:33:09.000 Uh, change and fault strike orientation that's consistent with. 00:33:09.000 --> 00:33:19.000 a regional compression or restraining bend. And ultimately, that restraining ban has uplifted and isolated the PillarPoint Plus. 00:33:19.000 --> 00:33:26.000 So here's another image looking at Pillar Point Bluff, and we're going to zoom in on this landslide, kind of straight in the center. 00:33:26.000 --> 00:33:30.000 And that's the site that we use to exploit the headscarp. 00:33:30.000 --> 00:33:38.000 Along the, kind of, southern margin. Okay. So, looking at… That's the exposure, and if you look at it. 00:33:38.000 --> 00:33:44.000 More in orthomosaically, so portion of it, this is the orthomosaic, um, adding. 00:33:44.000 --> 00:33:55.000 some interpretations… And some color. The units, so Unit 1 is the Prisma formation, Unit 2 is the Marine Terra Sands, and Unit 3 is the capping alluvial structure. 00:33:55.000 --> 00:34:02.000 uh, happening a Louisville unit. And you can see, ultimately, that the Alluvium has been thrust on top of itself multiple times. 00:34:02.000 --> 00:34:12.000 And I think one of the questions that remain is that where is the dextral slip through this area? As this is primarily a low-angle reverse fault. 00:34:12.000 --> 00:34:14.000 And I think I'll leave it there for now. 00:34:14.000 --> 00:34:38.000 Thanks. 00:34:38.000 --> 00:34:42.000 Hello everyone, greetings. This is an update of the North Hayward-Rogers Creek. 00:34:42.000 --> 00:34:46.000 Uh, evidence from San Pablo Creek and San Pablo. 00:34:46.000 --> 00:34:54.000 California, work in preparation. In San Paldo Creek, events E1 and E5 are recorded by large offsets. 00:34:54.000 --> 00:34:59.000 Intervening events E2, E3, and E4 minor, likely triggered creep. 00:34:59.000 --> 00:35:07.000 expressions. Calibrated age balance for San Pablo E1, E5, or… Common Era 1710. 00:35:07.000 --> 00:35:17.000 and 1305 at 2 Sigma. San Pablo E1 and E5 ages overlap with Rogers Creek E1 and E2. 00:35:17.000 --> 00:35:22.000 San Pablo Bay, E1 and E2. El Cerrito E1 and E2. 00:35:22.000 --> 00:35:31.000 and South Hayward E2 and E5. Combined North Hayward, Rogers Creek data indicate E1 and E2 ages. 00:35:31.000 --> 00:35:35.000 for the system are about $1,750 and $13.50 Common Era. 00:35:35.000 --> 00:35:40.000 Indicating a recurrence interval of 400 years for the two most recent events. 00:35:40.000 --> 00:35:48.000 If this is repeating behavior, subsequent potential full system rupture is passed at about 2150. 00:35:48.000 --> 00:35:59.000 Next. A, um… paleoseismic sites, I don't know if you see my pointer, probably not, um… All right, Rogers… alright, BB and Triangle G Ranch. 00:35:59.000 --> 00:36:06.000 Uh, San Pablo, uh… Watch study in San Pablo Bay, this study at San Pablo Creek. 00:36:06.000 --> 00:36:11.000 Mayor Vista Golf Course, and. South Hayward, Tyson's Lagoon. 00:36:11.000 --> 00:36:23.000 Next. creep data from Shirazi and Bergman 2012, show the northern segment of the Hayward Fault is creeping at close to its full rate. 00:36:23.000 --> 00:36:30.000 And the 1868 rupture, presumably. filled in this, uh, low creeping zone. 00:36:30.000 --> 00:36:35.000 So, with this low strain rate, seeing large ruptures of this, uh. 00:36:35.000 --> 00:36:40.000 site was rather surprising. Next. 00:36:40.000 --> 00:36:48.000 This is a, uh, trench log. showing large stratigraphic offset across the E1 horizon. 00:36:48.000 --> 00:36:53.000 and a large fisher fill. So, a dramatic, uh, large offset. 00:36:53.000 --> 00:36:59.000 Innervating small events, and then. large soil offset of more than a meter. 00:36:59.000 --> 00:37:04.000 for E5. Next. Combining data from. 00:37:04.000 --> 00:37:10.000 Rogers Creek, San Pablo Bay. San Pablo site. 00:37:10.000 --> 00:37:18.000 Hayward North, and… Tyson's Lagoon constrained slip rate, or event times to 1350 and 1758. 00:37:18.000 --> 00:37:25.000 Fairly timeless. Next. Long-term conceptual model. 00:37:25.000 --> 00:37:30.000 Um, suggest possibly on. cycling behavior between full system ruptures and south Hayward ruptures. 00:37:30.000 --> 00:37:35.000 with an anticipated rupture at $21.50, not 2200, which was our. 00:37:35.000 --> 00:00:00.000 estimate. When we last presented this. Thank you. 00:00:00.000 --> 00:00:30.000 But, same difference. 00:37:50.000 --> 00:37:51.000 That's not me. 00:37:51.000 --> 00:37:56.000 Sorry, I thought Danielle was next. 00:37:56.000 --> 00:37:59.000 Uh, hi everybody, um… 00:37:59.000 --> 00:38:05.000 Just wanted to give you guys an update on our pale seismic trench project in the Sacramento-San Joaquin Delta. 00:38:05.000 --> 00:38:11.000 So, for those of you who have been following along on our work in cryptic structures in the Delta, some of this will be familiar, but there's some new 00:38:11.000 --> 00:38:13.000 age control at the end. 00:38:13.000 --> 00:38:23.000 Um, so, the Delta's an interesting place to… to look at active faults because there is a fair amount of strain, not compared to the major plate boundary structures to the west, but… 00:38:23.000 --> 00:38:26.000 a couple millimeters of… of… 00:38:26.000 --> 00:38:30.000 genetic movement every year, um… 00:38:30.000 --> 00:38:35.000 The Montezuma Hills are one of the few areas of actual topographic relief in the Delta. 00:38:35.000 --> 00:38:42.000 Um, and, uh, they actually have some topographic asymmetry from east to west, uh, suggesting 00:38:42.000 --> 00:38:48.000 that, uh, faults on the west side, particularly in the southwest, to accommodate the uplift of the Montezuma Hills. 00:38:48.000 --> 00:38:54.000 Um, interesting, there is no fault in this location on current hazard maps, but we did… 00:38:54.000 --> 00:38:57.000 excavated a trench out there in fall of 2024. 00:38:57.000 --> 00:38:59.000 Um, and… 00:38:59.000 --> 00:39:04.000 Uh, the short story here, uh, is that 00:39:04.000 --> 00:39:08.000 Uh, this fault does seem to be, uh, quaternary active. 00:39:08.000 --> 00:39:10.000 Um, so if we want to break out this… 00:39:10.000 --> 00:39:12.000 tiny, uh, trench log of a giant trench. 00:39:12.000 --> 00:39:18.000 into a couple of simple units. Uh, the yellow zone at the uphill end of the trench, this is the east end. 00:39:18.000 --> 00:39:22.000 um, is Channelized Sands and silts, uh, course. 00:39:22.000 --> 00:39:24.000 sand, um… 00:39:24.000 --> 00:39:30.000 The downslope zone to the west is in blue, uh, is laminar layers of mud and silt. 00:39:30.000 --> 00:39:35.000 They're gently dipping westward, um, but seem to be, uh, sort of estuiring, or… 00:39:35.000 --> 00:39:37.000 or mudflat deposits. 00:39:37.000 --> 00:39:44.000 I mean, there's extensive overprinting of soil horizons in that zone, and in between them, we have this pink 00:39:44.000 --> 00:39:48.000 area that we're calling the colluvial zone, which is enigmatic and mostly massive. 00:39:48.000 --> 00:39:54.000 Um, but is interpreted to contain, or we interpret it to contain sediments that are coming off of 00:39:54.000 --> 00:39:57.000 a SCARP immediately following a slip on a fault. 00:39:57.000 --> 00:40:03.000 So, if we zoom in on that zone, it's this area in brown, and this is what we're going to focus on 00:40:03.000 --> 00:40:08.000 Uh, for the next couple of slides here. 00:40:08.000 --> 00:40:13.000 So, uh, first off, I'm gonna show you some results from portable luminescence work. 00:40:13.000 --> 00:40:17.000 Uh, that we've done in collaboration with Harrison Gray. 00:40:17.000 --> 00:40:25.000 And, uh, for those of you who are not familiar with this technique, it gives us a way to get a relative age on a whole lot of samples all at once. 00:40:25.000 --> 00:40:31.000 Um, so we can calibrate this with traditional luminescence dates, and we're in the process of doing that. 00:40:31.000 --> 00:40:34.000 Um, but because it is comparatively low cost, and 00:40:34.000 --> 00:40:37.000 easy to process. You can run a ton of samples. 00:40:37.000 --> 00:40:39.000 Um, at once, and so when we… 00:40:39.000 --> 00:40:44.000 do that, we have a grid here of 120 samples or so, and we see this 00:40:44.000 --> 00:40:53.000 prominent age break in the lower left corner, and there's maybe a second age break in there hiding, but this looks like it's, uh, one, maybe two events on this fault. 00:40:53.000 --> 00:40:58.000 We also just got back our traditional luminescent samples from this trench, and they're startlingly young. 00:40:58.000 --> 00:41:01.000 Um, the deepest samples in the trench are 30,000 years. 00:41:01.000 --> 00:41:11.000 old with the Central Age model, if you use a minimum age model, they're more like 15,000 years old. Um, and the point that I'd like to make here is that this is a site that is about 30 meters above sea level. 00:41:11.000 --> 00:41:20.000 Um, so if these are indeed estuary and muds, then we're looking at an uplift rate of about a millimeter a year, and this is not even on the fault itself. This is a regional 00:41:20.000 --> 00:41:22.000 uplift rate across the, uh, 00:41:22.000 --> 00:41:29.000 fault monoclein in this location. So, um, these uplift rates are maybe significantly higher than we expected. 00:41:29.000 --> 00:41:40.000 And stay tuned, we have all kinds of additional questions that we're hoping to tease out. 00:41:40.000 --> 00:41:50.000 Hi, um, I'm Dana Marino from the Nevada Seismological Laboratory, and today I'm going to be talking about my master's project, which, uh… 00:41:50.000 --> 00:41:58.000 looks at the Walker Lane Seismic hazard in the Reno Sparks urban area. 00:41:58.000 --> 00:42:10.000 So, the Walker Lane is this northwest-oriented trans-tentional system that spans both California and Nevada, south of the Garlic Fault, it's more commonly referred to as the Eastern California Share Zone. 00:42:10.000 --> 00:42:20.000 But north of the Garlic Vault, it's called the Walker Lane. It's sought to accommodate approximately 20% of the relative plate motion between the North American and Pacific plates, 00:42:20.000 --> 00:42:25.000 And it's composed of numerous short strike, slip, and normal faults that are linked at high angles. 00:42:25.000 --> 00:42:41.000 To each other. Um, because there are so many faults distributing the slip in this area, the recurrence interval may be long relative to the actual hazard that lives on top of this fault network. 00:42:41.000 --> 00:42:48.000 So, the motivation behind my project is that the Reno Sparks area, which is in the northern Walker Lane, 00:42:48.000 --> 00:42:56.000 lies in a region that has been host to many historical earthquakes, and is thought to essentially 00:42:56.000 --> 00:43:00.000 be a region that is capable of producing other potentially damaging earthquakes. 00:43:00.000 --> 00:43:16.000 In addition to that, currently mapped faults from Q faults don't seem to quite align with the geomorphology seen in newer LiDAR datasets. So, my current work involves doing some geomorphic mapping of 00:43:16.000 --> 00:43:22.000 fault-related features, and trying to refine the currently mapped fold traces and 00:43:22.000 --> 00:43:28.000 maybe kind of getting rid of some noise that can be seen in this picture. 00:43:28.000 --> 00:43:34.000 Uh, more recently, I've been scouting some sites to do some shallow geophysics. 00:43:34.000 --> 00:43:38.000 Uh, to kind of figure out whether some fault scarps or… 00:43:38.000 --> 00:43:44.000 what we think are false scarps, uh, in downtown Reno, whether or not they offset some younger strata. 00:43:44.000 --> 00:43:47.000 Which is pretty important, given that this is… 00:43:47.000 --> 00:43:50.000 somewhat of a dense urban area. 00:43:50.000 --> 00:43:59.000 So… main takeaways of what I've been doing so far is that QFaults is in need of updates in the Reno urban area, and 00:43:59.000 --> 00:44:04.000 I'm currently doing some mapping for that, and that false carps in the LiDAR data sets show 00:44:04.000 --> 00:44:13.000 maybe some faults in downtown Reno, north and south of the Truckee River, where currently fault traces are pretty sparse in Q-Vaults. 00:44:13.000 --> 00:44:25.000 That's it. Thank you. 00:44:25.000 --> 00:44:32.000 Hi, uh, my name is Chelsea Scott, and along with my team at Arizona State University and Pacific Gas and Electric, 00:44:32.000 --> 00:44:37.000 We're looking at the question of how well we can map 00:44:37.000 --> 00:44:44.000 Predict the location of ruptures in the next earthquake based on mapping faults. 00:44:44.000 --> 00:44:46.000 before that earthquake. 00:44:46.000 --> 00:44:56.000 And the application of this work is to understand and ultimately mitigate the seismic hazard, and specifically the fault displacement hazard, 00:44:56.000 --> 00:45:01.000 to critical infrastructure that must cross active faults. 00:45:01.000 --> 00:45:10.000 So, on the next slide, uh, you can see, uh, the first part of this work, which focused on constraining the uncertainty in the mapped fault position. 00:45:10.000 --> 00:45:17.000 Specifically, this figure is looking at the 2016 Kumamoto earthquake in Japan. 00:45:17.000 --> 00:45:22.000 And in blue, you can see faults that were mapped from remote sensing data. 00:45:22.000 --> 00:45:26.000 acquired before the earthquake. 00:45:26.000 --> 00:45:30.000 And then red are the co-seismic ruptures from that 2016 earthquake. 00:45:30.000 --> 00:45:37.000 And what we see here is that the faults don't exactly predict the location 00:45:37.000 --> 00:45:44.000 of the subsequent co-seismic ruptures. And so this has important implications for the fault displacement hazard. 00:45:44.000 --> 00:45:55.000 Um, and then we quantified this uncertainty and found that in a good situation, there is typically tens of meters of separation, 00:45:55.000 --> 00:45:59.000 between the faults and subsequent ruptures. 00:45:59.000 --> 00:46:04.000 And sometimes much larger distances in less good scenarios. 00:46:04.000 --> 00:46:08.000 And that's summarized in our 2023 paper. 00:46:08.000 --> 00:46:13.000 And then on the next slide, looking at the current part of this work, 00:46:13.000 --> 00:46:22.000 Um… she's not quite there yet, and I can see it. And this is looking at, uh, developing a GIS-based tool. 00:46:22.000 --> 00:46:29.000 that felt mappers can use to plot a well-informed uncertainty based on their mapped fault trace. 00:46:29.000 --> 00:46:33.000 So in the figure, you can see the line work, which shows the mapped fault, 00:46:33.000 --> 00:46:37.000 And then the red is the uncertainty buffer. 00:46:37.000 --> 00:46:42.000 And the idea is that these uncertainty buffers contain most deformation, 00:46:42.000 --> 00:46:45.000 of engineering significance. 00:46:45.000 --> 00:46:50.000 And so we are currently in the stages of refining some of the statistics that go into this tool, 00:46:50.000 --> 00:46:53.000 And the tool itself. 00:46:53.000 --> 00:47:03.000 And we've been, uh, having frequent meetings with different stakeholders on the project. So if you're interested in either participating in these meetings or testing this tool, 00:47:03.000 --> 00:47:11.000 Later in the summer, uh, please feel free to email me at cpscott1 at ASU, and I'd love to hear from you. 00:47:11.000 --> 00:47:12.000 Thank you. 00:47:12.000 --> 00:47:22.000 Hold on. 00:47:22.000 --> 00:47:25.000 Okay. I guess I get to go now. Yay! 00:47:25.000 --> 00:47:30.000 Um, let me get my controller. 00:47:30.000 --> 00:47:35.000 I'm not moving them. They're not going. 00:47:35.000 --> 00:47:45.000 There they go. Okay. Hi, my name's Danielle Madugo, and today I'll be sharing a new preliminary mapping of the Concord Fault shown in red. 00:47:45.000 --> 00:47:52.000 The Concord Fault is seismically active. Here, the Waldhauser relocated Seismicity is plotted, and the maximum magnitude of black circles is 00:47:52.000 --> 00:47:59.000 4.9. The Concord Fall has not hosted a large earthquake historically, however, the largest earthquake possibly associated with it 00:47:59.000 --> 00:48:03.000 is a magnitude 5.4 in 1955. 00:48:03.000 --> 00:48:06.000 The fault was first recognized in the 1930s as a groundwater barrier, 00:48:06.000 --> 00:48:13.000 Uh, after ranchers sued the local water district for pumping water that they thought was adversely affecting their wells. 00:48:13.000 --> 00:48:19.000 In 1973, Sharp mapped it and documented creep evidence at the northern and central sections. You can see that orange 00:48:19.000 --> 00:48:21.000 arrows. Um… 00:48:21.000 --> 00:48:28.000 His map was used to inform the AP zones in… the first AP zones in 1974. 00:48:28.000 --> 00:48:37.000 1979 saw two alignment reinstallations, and now there's 55 years of creep data, although who'll know how long that'll last. 00:48:37.000 --> 00:48:41.000 In 1993, the first updates to the original AP zones were 00:48:41.000 --> 00:48:45.000 Released by the state, and the southernmost known extent of creep 00:48:45.000 --> 00:48:49.000 remained there until… 00:48:49.000 --> 00:48:57.000 2025! 90 years after it was first recognized, and after multiple decades refining its location and measuring its slip rates, 00:48:57.000 --> 00:49:03.000 A new, actively creeping strand trace of the fault is mapped by Elliot et al. 00:49:03.000 --> 00:49:08.000 For all the details on this new trace, see Austin's talk on Thursday, 1045. 00:49:08.000 --> 00:49:14.000 This new active trace necessitated a re-evaluation of the Concord Vault by the state. 00:49:14.000 --> 00:49:18.000 So we did. Standard mapping tools we use include aerial photos, 00:49:18.000 --> 00:49:21.000 and field recon. New data since 00:49:21.000 --> 00:49:27.000 The last release is LiDAR, which was only helpful outside the urbanized areas to the south. 00:49:27.000 --> 00:49:36.000 There have been roughly 200 AP site-specific fault investigations conducted in the zones, and this new trace mostly resides outside the previous AP zones, 00:49:36.000 --> 00:49:42.000 Likely aiding its escape from detection, which one trust trench missed by just tens of feet. 00:49:42.000 --> 00:49:47.000 Uh, UAVSAR data proved critical for updating the ends of the fault zone. 00:49:47.000 --> 00:49:56.000 And so this analysis of fault parallel motion by Katya Tomofieva is one of several used to identify the creeping strands of this Concord Vault. 00:49:56.000 --> 00:50:00.000 Leading to significant changes in red, where the active traces are mapped. 00:50:00.000 --> 00:50:09.000 At the northern end, the active traces shifted eastward to where deflected railroad sightings were identified in sharps mapping and confirmed for the previous zone release. 00:50:09.000 --> 00:50:18.000 This northerly attitude more directly trends towards the Green Valley Fault. Nothing changed along the central section of the fault, it is already well located by AP Studies and evidence of creeping. 00:50:18.000 --> 00:50:22.000 Elliot et al.'s new trace shifts the main active fault west 00:50:22.000 --> 00:50:25.000 Further outboard of Lime Ridge and into Ignacio Valley. 00:50:25.000 --> 00:50:28.000 And I used UAPSAR analyses by Eric Fielding to extend CREEP evidence 00:50:28.000 --> 00:50:35.000 Further south of the Elliot L. Trace, before adding a non-creeping strand even farther south. 00:50:35.000 --> 00:50:40.000 Uh, here we see how the new faults in the zones in… 00:50:40.000 --> 00:50:49.000 pink compared with the old zones in green. Internal review of this work is in progress, and preliminary map release is due late spring, followed by official maps in the fall. If you have any more data, please share. 00:50:49.000 --> 00:50:59.000 Thank you. 00:50:59.000 --> 00:51:05.000 Okay, thanks to all the speakers for your great talks. We do actually have… 00:51:05.000 --> 00:51:11.000 time until 2.15 Pacific, or a live Q&A. 00:51:11.000 --> 00:51:23.000 Um, so please, uh, raise your hand if you have a question for any of our 15 speakers. 00:51:23.000 --> 00:51:27.000 And it looks like, um, Christy has a question. 00:51:27.000 --> 00:51:29.000 For Danielle in the chat. 00:51:29.000 --> 00:51:34.000 Uh, it's a newly identified strand, so brand new, no one knew about it. 00:51:34.000 --> 00:51:41.000 Um, the geomorphic mapping in the previous FER actually did have it mapped 00:51:41.000 --> 00:51:50.000 a zoned part of it, um, and then also they had mapped geomorphically another piece, but didn't zone that part. But basically, 00:51:50.000 --> 00:51:52.000 Um, south of that, it's… 00:51:52.000 --> 00:51:58.000 uh… brand new. 00:51:58.000 --> 00:52:02.000 And there's a few more questions for you in the chat, Danielle, if you want to take a look at those, and then we can go to Evan's question. 00:52:02.000 --> 00:52:07.000 Let's see, uh… 00:52:07.000 --> 00:52:13.000 Transcription? No, not a transcription error. It's basically… it's brand new. 00:52:13.000 --> 00:52:16.000 Which is amazing. 90 years after this 00:52:16.000 --> 00:52:19.000 fault, which is in an urbanized area, has been 00:52:19.000 --> 00:52:23.000 Documented, studied, mapped multiple times, and we're still finding 00:52:23.000 --> 00:52:27.000 new faults. 00:52:27.000 --> 00:52:33.000 And Brian asks, are you eliminating the old AP zone east of the fault in the southern end? 00:52:33.000 --> 00:52:38.000 No. Uh, we are in the, uh, northern area. 00:52:38.000 --> 00:52:41.000 Uh, yeah, sorry, I don't have my slide up. 00:52:41.000 --> 00:52:47.000 But in some cases, we are removing the eastern strand. In other cases, we are not, because there is 00:52:47.000 --> 00:52:51.000 trench evidence for it. 00:52:51.000 --> 00:52:55.000 Thanks. Evan, do you want to go ahead and ask your question? 00:52:55.000 --> 00:53:00.000 Oh, yeah, my question's actually for Tyler, so I guess if anyone still has questions for Danielle, they can go first. 00:53:00.000 --> 00:53:03.000 I'm okay. 00:53:03.000 --> 00:53:12.000 Okay, um, yeah, Tyler, uh, really interesting work. I grew up in Half Moon Bay, so I'm curious about the San Gregorio Fault there. 00:53:12.000 --> 00:53:20.000 Are you able to kind of put some constraints on uplift rate and then inversely, like, slip rate on the fault, and maybe… 00:53:20.000 --> 00:53:24.000 like, maximum slip you would expect in a single event, or…? 00:53:24.000 --> 00:53:28.000 What are you able to tell from the data? I know you had to hurry up at the end there. 00:53:28.000 --> 00:53:37.000 Yeah, yeah, it's a good question. Um… We don't really have any, at least in the data, we don't have any specific. 00:53:37.000 --> 00:53:41.000 piercing points to give us a lateral slip on it. 00:53:41.000 --> 00:53:51.000 Uh, on the Sanger Gorio, on the Seal Cove trace of it, um, but I think… one of the things that we could use the uplift rate as kind of a minimum. 00:53:51.000 --> 00:53:57.000 Uh, for the slip rate across that area, and potentially, you know, there's different models out there where you can do. 00:53:57.000 --> 00:53:59.000 you know, if you want to have one component of it. 00:53:59.000 --> 00:54:11.000 uh, one-to-one lateral to uplift, you know, you would say that there's, you know, significantly more. Um, there is one paper… Uh, I don't know if it was published, I did a slip rate. 00:54:11.000 --> 00:54:24.000 Uh, on the Pillar Point Bluffs. trying to use a deflected drainage, uh, by Gary Simpson et al, um, a number of years back, and they came up with something around 4 millimeters a year, I think. 00:54:24.000 --> 00:54:30.000 Um, the other thing that's tricky about the San Gregorio is that there's another trace offshore. 00:54:30.000 --> 00:54:35.000 So, it's kind of this distributed system, so they get the total slip rate across the system would be. 00:54:35.000 --> 00:54:40.000 Um, tricky to do, but I think it would be really good to get one. 00:54:40.000 --> 00:54:51.000 On this strand, but again, it's hard with the, uh… the resources and kind of the stratigraphy that we have, that I've found. So, yeah. 00:54:51.000 --> 00:54:55.000 Yeah. 00:54:55.000 --> 00:54:59.000 Okay, any more questions? 00:54:59.000 --> 00:55:07.000 We had 15 speakers and asking questions to any of them is fair gain. 00:55:07.000 --> 00:55:10.000 There's still, Danielle, a lot of… 00:55:10.000 --> 00:55:12.000 discussion about your talk in the chat. 00:55:12.000 --> 00:55:14.000 Yeah, I'm trying to answer. Okay, so… 00:55:14.000 --> 00:55:18.000 Um, basically, Sarah used a bunch of different images, um, 00:55:18.000 --> 00:55:24.000 created by different people, and so the pixel resolutions for some of those were, like, 50 meters, so… 00:55:24.000 --> 00:55:27.000 Um, it gets mapped based on 00:55:27.000 --> 00:55:32.000 you know, where it is, I see it, and we saw it in the field, and where Austin saw it in the field. 00:55:32.000 --> 00:55:35.000 Um, we're specifically were you… 00:55:35.000 --> 00:55:39.000 uh, mentioning. 00:55:39.000 --> 00:55:42.000 Or thinking of. 00:55:42.000 --> 00:55:45.000 Oh, I… I think Brian was basically asking the same thing, like, sort of. 00:55:45.000 --> 00:55:46.000 Just south of the central segment, where the gradient was. 00:55:46.000 --> 00:55:48.000 Oh. 00:55:48.000 --> 00:55:58.000 east of… of the new mapping that Austin et al. Had done, and I… Just wanted to see what both of them gonna end up with the all-cause Priola, so I'm gonna get Ryder to encompass both of them. 00:55:58.000 --> 00:55:59.000 Yes. 00:55:59.000 --> 00:56:02.000 Or was it… I think we… I think we just had this conversation, so I think we're good. 00:56:02.000 --> 00:56:04.000 Yeah, oh. 00:56:04.000 --> 00:56:05.000 Roland had his hand up. Go rollin'! 00:56:05.000 --> 00:56:09.000 Yeah, I have another question for Danielle. You have a busy… 00:56:09.000 --> 00:56:13.000 afternoon today. The Concord Fault. 00:56:13.000 --> 00:56:15.000 what's the latest on… 00:56:15.000 --> 00:56:24.000 comparing its short-term creep rate, you know, that we can get from the creep meters or INSAR, and the long-term rates. I remember there were suggestions that 00:56:24.000 --> 00:56:27.000 It may not have much of an earthquake potential, because 00:56:27.000 --> 00:56:31.000 the two apparent slip rates are the same. Is that… 00:56:31.000 --> 00:56:32.000 still a possibility. 00:56:32.000 --> 00:56:38.000 So, yeah, Austin will be going over this in his talk on Thursday, but basically, the… 00:56:38.000 --> 00:56:48.000 Let's see, the creep rate for the downtown alignment raise was 3.2, 3.5 millimeters, and then we're getting similar, uh, ages 00:56:48.000 --> 00:56:50.000 Uh, on the new strand. 00:56:50.000 --> 00:56:53.000 And so, basically, that… 00:56:53.000 --> 00:56:57.000 The way we calculated those were we had these, um… 00:56:57.000 --> 00:57:04.000 city maps that, when you go to set out your, uh, your land and, and 00:57:04.000 --> 00:57:10.000 parcel it out, then, uh, those get dated, so those were used as kind of like a decadly average 00:57:10.000 --> 00:57:18.000 rate to apply to the curbs, because… I should let Austin tell you all of this. 00:57:18.000 --> 00:57:20.000 I don't want to take his thunder, because… 00:57:20.000 --> 00:57:21.000 He's on Thursday, but basically. 00:57:21.000 --> 00:57:25.000 Okay, I can be patient. Thank you so much. 00:57:25.000 --> 00:57:27.000 Appreciate it. 00:57:27.000 --> 00:57:32.000 And Chad, Dave is asking about future planned work? 00:57:32.000 --> 00:57:33.000 in the Montezuma Hills. 00:57:33.000 --> 00:57:35.000 Yeah, I was… I was typing a response, but I can answer here. 00:57:35.000 --> 00:57:36.000 We're live, so go ahead. 00:57:36.000 --> 00:57:40.000 Yeah, um, so yes, uh, we're… we're… 00:57:40.000 --> 00:57:45.000 Still trying to tease out some of the kinematic questions regarding that trench, um, and we're… 00:57:45.000 --> 00:57:48.000 Tossing around the idea of maybe excavating another 00:57:48.000 --> 00:57:53.000 trench along that structure at some point. Um, the other big project we've gotten going out right? 00:57:53.000 --> 00:57:59.000 out there right now is a Peak core paleo seismology study on a strand of the Pittsburgh-Kirby Hills fault that 00:57:59.000 --> 00:58:08.000 goes directly under the runways at Travis Air Force Base, and then projects out into the slough and disappears, um, but there's significant topography 00:58:08.000 --> 00:58:11.000 Uh, north of the slough along Strike of the Fault, so… 00:58:11.000 --> 00:58:14.000 Uh, we have pretty good evidence that it has… 00:58:14.000 --> 00:58:18.000 surface deformation history. Um, so we're looking at 00:58:18.000 --> 00:58:20.000 depths of, uh… 00:58:20.000 --> 00:58:23.000 both thickness of peat and depth of… 00:58:23.000 --> 00:58:30.000 various, sort of, sand and clay horizons within the peat section, uh, to try to tease out an earthquake history on that structure. So those are the two 00:58:30.000 --> 00:58:33.000 big things we've got going at the moment. 00:58:33.000 --> 00:58:36.000 Thanks, Chad. And maybe one more… 00:58:36.000 --> 00:58:39.000 Question from Ruth to Belle. 00:58:39.000 --> 00:58:41.000 About, um… 00:58:41.000 --> 00:58:48.000 speculating on an MMAX value for an earthquake through the central part of the creeping section. 00:58:48.000 --> 00:58:49.000 Belle, I don't… 00:58:49.000 --> 00:58:57.000 Yeah, I would… I would definitely not… there's a long chain of reasoning between what we see in a trench and an MX, but what I would. 00:58:57.000 --> 00:59:03.000 I would say we could maybe say a slip max. I would say it's unlikely. 00:59:03.000 --> 00:59:11.000 That there's been an… earthquake with more than a meter or so of surface slip. 00:59:11.000 --> 00:59:23.000 Um, and based on the, uh… evidence that we see in the trenches. So you can… parlay that into an MX however you like with your favorite model. 00:59:23.000 --> 00:59:24.000 And Roger, you have your hand up? 00:59:24.000 --> 00:59:25.000 Thanks, Bill. 00:59:25.000 --> 00:59:32.000 Yeah, I have a… I have a general comment for all you guys digging trenches and finding creeping faults. 00:59:32.000 --> 00:59:40.000 do let me know when you open up a trench, so that when you close it, I can put a creep meter in exactly the same place without going through any permission. 00:59:40.000 --> 00:59:49.000 Um, the point is that creep meters are now very inexpensive, and finding permission to put things in the ground is very 00:59:49.000 --> 00:59:58.000 tedious. So, if you're interested in how your fault is actually creeping, let me know. 00:59:58.000 --> 00:59:59.000 Okay. 00:59:59.000 --> 01:00:03.000 We thought of you, Roger. It wasn't feasible for that trench, unfortunately, but. 01:00:03.000 --> 01:00:05.000 If we do another one, I'll call you, I promise. 01:00:05.000 --> 01:00:08.000 Okay. 01:00:08.000 --> 01:00:15.000 Okay, thanks again to our speakers and everyone for the great discussion. Um, we are now at our break. 01:00:15.000 --> 01:00:19.000 So I'll hand it back to Sarah and John. 01:00:19.000 --> 01:00:31.000 Yes, so there was a 15-minute break until 2.30 PM Pacific for everybody who is not in the next session, so that means if you all Bonowitz, Vandalint. 01:00:31.000 --> 01:00:34.000 I feel good! 01:00:34.000 --> 01:00:35.000 I knew that I wouldn't… 01:00:35.000 --> 01:00:38.000 Please stick around to get yourself set up tech-wise. Everyone else, you get 15 minutes to stretch! 01:00:38.000 --> 01:00:46.000 So good! So good! 01:00:46.000 --> 01:00:52.000 And we can pause recording now, but then someone has to remind us to start it again later.