Abstract
We present results of a preliminary analysis for source parameters of the 29 May 2004 offshore Uljin earthquake. The analysis is based on a set of broadband and short period velocity seismograms, and accelerograms recorded by seismic networks in southern Korea. The estimated parameters of the mainshock are as follows: origin time 19∶14∶25.82 in Korean local time (10∶14∶25.82 UT), latitude 36.626°N, longitude 130.054°E, depth 18 km, magnitudeM w 5.1, stress drop 28 bars, one focal plane 337°, 56° and 78°, and the other plane 178°, 36° and 107° in strike, dip and rake, respectively. Three aftershocks ofM w 2.3, 2.0 and 2.4 occurred within source region of the mainshock, and two other events ofM w 2.5 and 3.5 at epicenters beyond the rupture area are presumed to be triggered dynamically by the 29 May 2004 earthquake. The largest ground acceleration, 2.62%g, was instrumentally recorded at Pohang, 90.4 km south-west of the mainshock epicenter. The maximum instrumental intensity is estimated as V and VI in Modified Mercalli Intensity scale excluding and including local effects, respectively. There is a possibility that the mainshock-aftershock sequence and one of the dynamically triggered events are directly related to the Ulleung Fault.
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Kang, TS., Baag, CE. The 29 May 2004,M w =5.1, offshore Uljin earthquake, Korea. Geosci J 8, 115–123 (2004). https://doi.org/10.1007/BF02910189
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DOI: https://doi.org/10.1007/BF02910189