 Partially collapsed house in Suzu | |
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| UTC time | 2023-05-05 05:42:04 |
|---|---|
| ISC event | 626093124 |
| USGS-ANSS | ComCat |
| Local date | May 5, 2023 (2023-05-05) |
| Local time | 14:42:04JST (UTC+9) |
| Magnitude | 6.5MJMA 6.3Mw |
| Depth | 10 km (6 mi) (USGS) |
| Epicenter | 37°32′53″N137°17′56″E / 37.548°N 137.299°E /37.548; 137.299 |
| Fault | A previously unknown fault[1] |
| Type | Reverse |
| Areas affected | Japan |
| Max. intensity | JMA 6+–7 (MMI VIII) |
| Tsunami | 10 cm (0.33 ft)[2] |
| Landslides | Yes |
| Aftershocks | >300 (as of 21 October 2023) Largest isMw5.6[3][4] |
| Casualties | 1 dead, 49 injured |
On 5 May 2023, a MJMA 6.5 or Mw 6.3 earthquake struck off the coast ofIshikawa Prefecture,Japan.[5][6] It was located 49 kilometres (30 miles) northeast ofAnamizu,Hōsu District, with the town ofSuzu closest to the epicenter.[6]
The northeastern tip of theNoto Peninsula has been subject to anearthquake swarm for over two years; the earthquake is one of the largest events in this swarm, surpassing a MJMA 5.4 event that took place in June 2022.[7]
The earthquake was located in a zone of compressional deformation that is associated with theboundary between theAmur Plate and theOkhotsk microplate. In this area, the Okhotsk Plate is converging to the west-northwest towards the Amur Plate with a velocity of about 9 mm/yr and a maximum convergence rate of 24 mm/yr.[8] The Amur and Okhotsk plates are relatively small plates that are located between thePacific plate and theEurasian plate. The Pacific plate converges west-northwest towards the Eurasian plate at around 90 mm/yr.
The earthquake had a magnitude of Mww 6.2, Mw 6.3 or MJMA 6.5 according to theUnited States Geological Survey, GCMT andJapan Meteorological Agency respectively.[5] It struck at 14:42JST at a depth of 10 kilometers. According to the JMA a maximum intensity ofShindo 6+ was recorded, while the USGS estimated a maximumModified Mercalli intensity of VIII (Severe).[9] However, according to a seismic intensity distribution map created by theNational Research Institute for Earth Science and Disaster Resilience,Shindo 7 may have been recorded at Noroshi,Suzu.[10] The earthquake had afocal mechanism corresponding toreverse faulting.[11] A magnitude 5.6aftershock struck the area at 21:58 JST, succeeded by another aftershock, at 23:18 JST of magnitude 4.5, along with over 50 other aftershocks hitting on Saturday, between magnitude 2 and 5.[12][4][13]
| Intensity | Prefecture | Location |
|---|---|---|
| 6+ | Ishikawa | Suzu |
| 5+ | Ishikawa | Noto |
| 5- | Ishikawa | Wajima |
| 4 | Ishikawa | Nanao,Anamizu,Kanazawa |
| Niigata | Jōetsu,Nagaoka | |
| Toyama | Takaoka,Himi,Oyabe | |
| Fukui | Fukui |
Thirty-eight houses collapsed, 263 others were partially destroyed and 1,855 others were damaged, including 1,825 inSuzu and 30 inNoto.[16] One building each were also partially damaged inWajima andKanazawa.[17] Two people were rescued from collapsed buildings.[18] In Suzu, many buildings and structures were severely damaged, including a hotel, gravestones in a cemetery, a barn, a Shinto shrine and a police station. Landslides were also reported, causing the partial collapse or damage of mountainside houses. A man who fell from a ladder and suffered fromcardiac arrest succumbed to his injuries later in hospital.[9][13] At least 49 others were injured; 48 in Ishikawa[16] and another inToyama Prefecture.[19][20] Among the injured were two people who fell unconscious, two people injured by collapsed houses, a minor who was hit by a falling wardrobe and another who suffered burns. Two of the injured were in serious condition and the rest received minor injuries.[9][18][21][22][23][24] TheMitsukejima, which was previously affected byan intensity lower 6 earthquake the previous year, partially collapsed.[9] Two elevators were automatically shut down in theAbeno Harukas skyscrapers inOsaka, leaving some stranded before being evacuated.[2] Twenty homes had their electricity cut off in Suzu,[25] with more than 120 losing water supply.[26]
Due to the earthquake, around 1,600 people were evacuated. In Ishikawa Prefecture, 250 people took shelter in evacuation centers.[27] TheJapan Meteorological Agency warned the citizens of Ishikawa that strong aftershocks could occur for at least a week. The mayor ofSuzu, issuing an earthquake emergency advisory and evacuating multiple households, said that the city would not be needing the help ofJapan Self-Defense Forces due to the quake.[28] Prime ministerFumio Kishida also stated that more measures will be taken in the following days, while also communicating with multiple officials, also to prevent other casualties in the event of a strong aftershock.[29]
