Source depth dependence of micro-tsunamis recorded with ocean-bottom pressure gauges: The January 28, 2000 Mw 6.8 earthquake off Nemuro Peninsula, Japan
Micro-tsunami waves with a maximum amplitude of 4-6 mm were detected with the ocean-bottom pressure gauges on a cabled deep seafloor observatory south of Hokkaido, Japan, following the January 28, 2000 earthquake (Mw 6.8) in the southern Kuril subduction zone. We model the observed micro-tsunami and estimate the focal depth and other source parameters such as fault length and amount of slip using grid searching with the least-squares method. The source depth and stress drop for the January 2000 earthquake are estimated to be 50 km and 7 MPa, respectively, with possible ranges of 45-55 km and 4-13 MPa. Focal depth of typical inter-plate earthquakes in this region ranges from 10 to 20 km and stress drop of inter-plate earthquakes generally is around 3 MPa. The source depth and stress drop estimates suggest that the earthquake was an intra-slab event in the subducting Pacific plate, rather than an inter-plate event. In addition, for a prescribed fault width of 30 km, the fault length is estimated to be 15 km, with possible ranges of 10-20 km, which is the same as the previously determined aftershock distribution. The corresponding estimate for seismic moment is 2.7x1019 Nm with possible ranges of 2.3x1019-3.2x1019Nm. Standard tide gauges along the nearby coast did not record any tsunami signal. High-precision ocean-bottom pressure measurements offshore thus make it possible to determine fault parameters of moderate-sized earthquakes in subduction zones using open-ocean tsunami waveforms. Published by Elsevier Science B. V.
Citation Information
Publication Year | 2003 |
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Title | Source depth dependence of micro-tsunamis recorded with ocean-bottom pressure gauges: The January 28, 2000 Mw 6.8 earthquake off Nemuro Peninsula, Japan |
DOI | 10.1016/S0012-821X(03)00040-2 |
Authors | K. Hirata, H. Takahashi, E. Geist, K. Satake, Y. Tanioka, H. Sugioka, H. Mikada |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Earth and Planetary Science Letters |
Index ID | 70026267 |
Record Source | USGS Publications Warehouse |