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Scientific & Technical Reports - The 2002 Denali Fault earthquake

18-Nov-2002 update

PLEASE NOTE:   IF YOU ARE PLANNING ANY FIELD DEPLOYMENTS TO STUDY THE EARTHQUAKE, WE REQUEST THAT YOU PLEASE CONTACT DONNA EBERHART-PHILLIPS, USGS Anchorage, and make her aware of your plans.  She is in contact frequent contact with DGGS and UAF, hence knows of their plans as well.    Contact information for Donna:

Donna Eberhart-Phillips, USGS Anchorage (907) 786-7019;  (907) 786-7425 fax deberhart@usgs.gov 

More detailed information follows under the following headings.

1)    Geologic plans

2)    Preliminary geologic observations

3)    Geotechnical observations

4)    Seismological observations/instrument deployments

5)    Stress transfer modeling

6)    Geodetic observations

7) Remote Sensing

8) Gravity and Aeromagnetic

9)    InSAR coverage looks very promising

10)    Far distance effects of the seismic waves


GEOLOGIC PLANS


PRELIMINARY GEOLOGIC OBSERVATIONS

From Peter Haeussler:

Below are two photos regarding the offset avalanche path. The first shows me at the scarp where the avalanche debris is offset. The second shows the hillside where the avalanche path was. The observation was at the base of the right hand avalanche chute where all snow is removed down to bedrock. The headscarp of the avalanche chute was about 1400 feet higher than the fault trace, based on the helicopter's altimiter. The left hand avalanche chute is *not* offset by the fault. Both avalanche chutes appear to be of the same generation, and neither has new snow on them. If the avalanches had occurred after the 23 October event I think there would have been some new snow on them, and they probably wouldn't look so fresh. If you don't want these to occurr in the main event, I'd favor their origin to the foreshock on the morning of the 3 November. The argument against that is these avalanches scoured down to the bedrock, the entire snow surface failed. I know none of this relative timing information is conclusive, but it's intruiging. This is the ONLY avalanche chute I'm aware of that was offset by the fault.

Scarp where avalanche debris is offset

Hillside where the avalanche path was


GEOTECHNICAL OBSERVATIONS/PLAN

From Christina Neal afternoon of 11/15/02:

Peter and I just returned from Aeromap where we previewed negatives from their first 1:6000 run - the western ~half of the rupture zone. Overall, the images look very nice! Peter was pleased, which I take to be a good sign since he knows every crack and wrinkle. The fault trace is centered on most flight lines (let's hear it for the GPS coordinates sent quickly from the field!). Peter will receive a photo index map soon to compare with field maps to see if any key areas need to be reflown (weather, money, etc. allowing).

Attention landslide team: the remaining funds from the 50K air photo pot will only cover a single 1:25,000 flight line directly along the fault. That is the current flight plan; if you wish to revisit this strategy, please contact Peter.

Aeromap is on call to fly the 1:25,000 images during the next weather window. We could get lucky over the weekend, but I would not count on it. Winter seems (finally) to be here.

Aeromap expects the second cans of film on Monday, Peter and/or I will go take a look at those and report in.


SEISMOLOGICAL OBSERVATIONS/INSTRUMENTATION DEPLOYMENT


STRESS TRANSFER MODELING


GEODETIC OBSERVATIONS


REMOTE SENSING


REGIONAL GRAVITY AND AEROMAGNETIC DATA


INSAR COVERAGE LOOKS VERY PROMISING


FAR DISTANT EFFECTS OF THE SEISIMIC WAVES

 

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