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Scientific & Technical Reports - The 2002 Denali Fault earthquake

15-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


GEOTECHNICAL OBSERVATIONS/PLAN

From Christina Neal:

Yesterday (11/14) Aeromap was able to obtain nearly all the 1:6000 except for two small segments near the Slana River; weather looks poor for photography today.

Remaining: -final 1:6000 gaps near Slana River -1:25,000 flights (NB: we expect revised flight corridor instructions from Golden Landslide group this morning)

Concerns: -Aeromap needs some feedback on exact alignment for final photos from Peter; Bob Schweitzer is awaiting Peter Haeussler's call (Bob: 272-4495)

IMPORTANT: possible need for a larger open PO with Aeromap to cover future photo acquisitions and reprint requests to streamline purchasing. Possibly Mike B. in Menlo could work with Paula Winningham here in BRD to produce some expanded contract with Aeromap to streamline request/payment procedures. Precedent exists here in Anchorage (ESIC Greg Derocher) for reproductions on demand


SEISMOLOGICAL OBSERVATIONS/INSTRUMENTATION DEPLOYMENT

Lucy Jones, USGS Pasadena, has provided this update on the aftershop probabilities:

The rates are stabilizing. We continue to conclude that the b-value is higher than average, the total productivity is very low, and the decay rate is average to a little high. The expected number of M≥5 aftershocks in the month starting Friday, Nov. 15 is 4 to 5. The expected number for M≥4.5 is 16 and for M≥5.5 it is one.

The one concern I have is that except for the M5.8 20 minutes after the mainshock, the b-value is very high. The b-value calculated from M4.3-5.5 is 1.5! Below that it is lower, but that looks like a completeness issue rather than a truly lower b-value. I assume this represents a problem in the magnitude scale rather than a truly extreme b-value, but this is something that will need to be investigated.


STRESS TRANSFER MODELING

Greg Anderson, USGS Pasadena, has updated the stress transfer calculations. The main improvements are a better source model for the Nenana Mountain event and better choices of Coulomb modeling parameters. He has replaced the original file with the updated one at the same URL:

Stress Transfer Modeling Results


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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