Pilot Experiment to Monitoring Earthquakes in the Eastern Offshore of the Korean Peninsula using Ocean Bottom Seismometers (Yardbirds)

Abstract

The Korean peninsula is a typical example of an intra-plate region, where the current seismicity is low and the recurrence interval of damaging earthquakes is very long. Although the current seismicity is scattered and their magnitudes are low, historic earthquake records during the last 1900 years suggest the Korean peninsula should have experienced repeated strong shakings. A couple of historic earthquakes were noticeably accompanied by tsunami records along the east coast of the Korean peninsula. However, since the peninsula is largely regarded as an earthquake-safe region, little attention has been paid for the observation of offshore earthquakes. A team of collaborative research to monitor submarine earthquakes using both ocean-bottom and land-based seismometers has initiated the pilot experiment in the east offshore of the Korean peninsula. Primary objective of the pilot experiment is to monitor micro-seismic activity and to determine their precise locations to reveal their relations with active faults in the region. In October 2011, 4 OBSs (Yardbirds) and 7 temporary seismic stations in land were installed. We used KMA R/V GISANG 1 to deploy OBS. The pilot experiment had collected earthquake data for the 6 months. In mid-April, data from all 4 OBS and 7 temporary seismic stations were collected for the detailed analysis of micro-seismicity. We present the outline of the pilot experiare low, historic earthquake records during the last 1900 years suggest the Korean peninsula should have experienced repeated strong shakings. A couple of historic earthquakes were noticeably accompanied by tsunami records along the east coast of the Korean peninsula. However, since the peninsula is largely regarded as an earthquake-safe region, little attention has been paid for the observation of offshore earthquakes. A team of collaborative research to monitor submarine earthquakes using both ocean-bottom and land-based seismometers has in