Since the 1990s, the number of earthquakes with a magnitude of 6.0~ Mj are increasing. Some seismologists say that the seismic activity in West Japan is at its peak, and many earthquakes will occur, like the Great Hanshin earthquake. This earthquake is sometimes considered as one of those earthquakes.[citation needed]
Like the 2005 Fukuoka earthquake, it was announced that it "occurred in an area where seismic activity was relatively quiet", but earthquakes are possible anywhere in Japan and its surrounding areas. Also this earthquake's fault was out in sea, so it was not simulated in the seismic danger maps, since most of the faults simulated are inland faults. Some seismologists are trying to simulate these kind of earthquakes as well as inland earthquakes.[citation needed]
This type of earthquake was estimated to have occurred 1~2 times in the last 20,000 years (Frequency).[7]
Main shock
The Japan Meteorological Agency placed the earthquake at 37.3°N, 136.5°E, at a depth of 11 km. It estimated the magnitude at 7.1, but later revised its estimate to 6.9. The earthquake had a maximum three-component vector sum peak ground acceleration of 1,304 cm/s2 (1.33 g).[8] It occurred in a big seismic gap. Shaking in Wajima was very close to Shindo 7. It was the first time that Shindo 6- or more was observed in Ishikawa prefecture. It was also the 2nd time that Shindo 5- or more was observed in Toyama prefecture. Shaking was felt as far as Oshamanbe in the north, to Hiroshima in the west and Nahari in the south (Extent).[6]
Geophysical effects
The earthquake moved Shika 25 cm southwest, and Anamizu 15 cm northwest.[3] It also shifted an erosion terrace formed in the ice age and the sediment on top by 10 cm.
According to the National Research Institute for Earth Science and Disaster Prevention, the pattern of the shaking was similar to the shaking in the Great Hanshin earthquake and the 1994 Northridge earthquake, called the "killer pulse": Pulse waves with a frequency of 1–2 seconds. This kind of shaking heavily damages buildings with around 2 floors. The shaking then got larger as it reached softer ground like alluvial plains, causing major damage.
A 52-year-old woman died after a tōrō (stone lantern) collapsed and hit her head in Wajima.[1][11]
22 cracks were found in the runway of Noto Airport. The runway was repaired by March 26.
Some parts of the Noto Toll Road collapsed, making people leave their cars on the road after they evacuated. The roads were completely repaired by November 30.
According to estimates about 110,000 houses had power outages, 13,250 houses had no water supply, and 260 houses' phones stopped working.
Many other houses had no gas supply after the earthquake.
Largest aftershocks are blue, and 4.8~ Mj earthquakes are light blue.
Response
The Cabinet Office
At 9:45, an emergency meeting for this earthquake was held at the Prime Minister's Official Residence. Government damage inspecting teams under command of Kensei Mizote were sent to the epicenter area from the 25th to the 26th.
About 6 months after the earthquake, rumors spread for a little while within the 13–18-year-old range of the residents of Toyama Prefecture that a massive earthquake would occur in Toyama Prefecture.[citation needed]
