Earthquake Offshore Fukushima Prefecture on November 22, 2016 - Distribution of Hypocenters and Tsunami waveforms (Analysis using S-net data)
On November 22, 2016 at 05:59 (JST), there was an earthquake of Mjma 7.4 (Mw 7.0: F-net) offshore Fukushima prefecture. Seismic waves from the main shock and aftershocks were observed by seismographs of S-net and Hi-net, and the distribution of hypocenter was obtained from the readings of travel times (Figure 1). Aftershocks are located in the range of 30 km southwest of the epicenter of the main shock, and are concentrated shallower than 30 km in depth. The southeast part of the aftershock region is deep and the distribution of aftershocks are plane-shaped, dipping to southeast.
Water pressure gauges of S-net observed water pressure variation, equivalent to maximum 40 cm in the vicinity of the hypocenter, accompanying the propagation of tsunami. Clear succeeding waves arrived after about 40 to 60 minutes from the first wave arrivals. At some stations, the amplitude of the succeeding waves were of the same order of the first waves.
National Research Institute for Earth Science and Disaster Resilience
[Evaluation of Seismic Activities for November 2016 (December 9, 2016)]