The 2007 Noto Peninsula earthquake (能登半島地震, Noto-hantо̄ Jishin) occurred on March 25, 2007, in the Hokuriku region of Japan.

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2007 Noto Peninsula earthquake

能登半島地震
UTC time	2007-03-25 00:41:57
ISC event	11703278
USGS-ANSS	ComCat
Local date	March 25, 2007 (2007-03-25)
Local time	9:41:48 JST (UTC+09:00)
Duration	About 30 seconds[1]
Magnitude	6.9 Mj (6.7 Mw)[2]
Depth	11 km (7 mi)
Epicenter	37.3°N 136.5°E / 37.3; 136.5
Type	Intraplate, Oblique-slip[3]
Areas affected	Japan
Max. intensity	MMI X (Extreme)+[4] JMA 6+
Peak acceleration	0.96 g 945.4 Gal
Tsunami	Up to 22 cm in Suzu
Landslides	Yes
Aftershocks	500~
Casualties	1 dead, 356 injured[5]

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At 9:41:58 a.m. on March 25, 2007, a magnitude 6.9 earthquake struck the Hokuriku region of Japan, near the Noto Peninsula. The earthquake shook the city of Wajima, the city of Nanao, and the town of Anamizu with a seismic intensity of 6+ on Japan's shindo scale.^[6] One death, in the city of Wajima, and at least 356 injuries have been reported.^[5]

This earthquake was the result of oblique-slip faulting.^[3] According to the Geospatial Information Authority of Japan, the fault was 21 km long, 14 km wide and shifted 1.4 m.^[3] By using sound waves, the National Institute of Advanced Industrial Science and Technology also found a fault 18~ km long that is supposed to have caused this earthquake.^[7]

This earthquake was an intraplate earthquake that occurred within the Eurasia Plate, near the boundary with the North American Plate. Noto Peninsula itself was created by pressure pushing up sediment from the south-east, and many folds and reverse faults are in the area. Some strike-slip faults are also found in the area. A 6.6 M_j earthquake also struck Ishikawa Prefecture on February 7, 1993.

Since the 1990s, the number of earthquakes with a magnitude of 6.0~ M_j 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]

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]

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]
• 25 track ballasts on the Noto Line were shifted after the earthquake.
• 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.
• Soil liquefaction was confirmed at the coasts near the epicenter and Himi port.
• Some people were trapped in elevators that stopped after the earthquake.

A tsunami advisory was immediately made for the Kaga coast and Noto coast, and a 22 cm wave^[12] hit shore about 30 minutes later.^[13]

More than 500 perceptible aftershocks were observed.

Largest aftershocks are blue, and 4.8~ M_j earthquakes are light blue.

• Since Toyama Prefecture had no damaging earthquakes for 116 years since the 1891 Mino–Owari earthquake, most residents commonly believed that no earthquakes ever occurred in that area.^{[citation needed]}
• 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]}
• An athletics competition that was to be held in Wajima was cancelled after the earthquake.^{[citation needed]}

• List of earthquakes in 2007
• List of earthquakes in Japan
• 2023 Noto earthquake
• 2024 Noto earthquake