Title of article :
Earthquake Location Accuracies in Norway Based on a Comparison between Local and Regional Networks
Author/Authors :
E.C. Hicks، نويسنده , , H. Bungum ، نويسنده , , F. Ringdal ، نويسنده ,
Issue Information :
ماهنامه با شماره پیاپی سال 2001
Pages :
13
From page :
129
To page :
141
Abstract :
Detailed studies of the low to intermediate seismicity in two coastal regions of Norway have been used in a comparison between earthquake locations from local high-precision networks on the one side and locations using a sparse regional array network on the other side. To this end, a reference set of 32 low-magnitude earthquakes have been located using two local temporary networks in northern and western Norway, with estimated epicenter accuracies better than 5 and 10ukm, respectively. Comparisons are made between the local network solutions and the NORSAR Generalized Beamforming (GBF) system, which provides automatic phase association and location estimates using the Fennoscandian regional array network. The median automatic GBF location error is of the order of 20–30ukm when four or more arrays detect the event, increasing to about 80–100ukm when only two arrays are available, and the automatic GBF bulletin is essentially complete down to magnitude ML = 2.0. Most of the mislocation vectors of the NORSAR GBF solutions are oriented perpendicular to the Norwegian coast, and with a tendency to pull the location in a southeasternly direction. The GBF performance is clearly better, both in terms of accuracy and completeness, than the performance of the automatic bulletin of the Prototype International Data Center (PIDC) which uses data from essentially the same network. The analyst reviewed NORSAR and PIDC bulletins show, not unexpectedly, an improvement in location accuracy compared to the automatic solutions and appear to be of similar quality for the few common events, with an average mislocation of about 20ukm. The NORSAR reviewed bulletin is more complete at low magnitudes compared to PIDC, and there appears to be a potential for significant improvements in the PIDC processing of small seismic events in this region.
Keywords :
Earthquake location , Local networks , Regional networks , seismic arryas.
Journal title :
Pure and Applied Geophysics
Serial Year :
2001
Journal title :
Pure and Applied Geophysics
Record number :
429304
Link To Document :
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