Accession Number : ADA470217


Title :   Collaborative Research: Calibration for IMS Stations in Eastern Asia


Descriptive Note : Technical rept.


Corporate Author : COLUMBIA UNIV PALISADES NY LAMONT-DOHERTY EARTH OBSERVATORY


Personal Author(s) : Richards, Paul ; Armbruster, John ; Khalturin, Vitaly L ; Kim, ,Won-Young ; Schaff, David ; Waldhauser, Felix ; West, Michael


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a470217.pdf


Report Date : Jul 2007


Pagination or Media Count : 286


Abstract : We have competed a three-year consortium effort led by Lamont to improve the capability to locate seismic events based on data acquired by 30 International Monitoring System (IMS) stations in East Asia We have developed and tested Source Specific Station Corrections (SSSCs) for Pn and Sn travel times at these 30 IMS stations (or suitable surrogates), and for 127 other stations used for validation testing. First we developed SSSCs via a 3-D model of the P-wave velocity for East Asia, and then we refined them empirically by applying a kriging algorithm to travel-time residuals for 525 Ground-Truth (GT) events whose epicenters in East Asia we showed are known to within 5 km. Using a leave-one-out approach, we relocated these 525 events recorded by various combinations of 140 regional stations. Miclocations were reduced for 66% of the events using the model-based SSSCs and for 85% of the events using kringed SSSCs. Meridian miclocation improved from 16.9 km to 11.4 km and 6.5 km respectively. Median error ellipse area was reduced from 2616 sq. km to 1633 sl.km, respectively. Error ellipse coverage was maintained at close to 90%.


Descriptors :   *VALIDATION , *MONITORING , *SEISMIC WAVES , TEST AND EVALUATION , CALIBRATION , ASIA , ELLIPSES , FAR EAST , CORRECTIONS , EPICENTERS , ERRORS , ALGORITHMS , STATIONS


Subject Categories : Seismology


Distribution Statement : APPROVED FOR PUBLIC RELEASE