On June 14, the 2008 Iwate earthquake struck the

Tōhoku region The , Northeast region, or consists of the northeastern portion of Honshu, the largest island of Japan. This traditional region consists of six prefectures (''ken''): Akita, Aomori, Fukushima, Iwate, Miyagi, and Yamagata. Tōhoku ret ...

of northeastern

Honshū , historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island ...

in Japan.

Japan Meteorological Agency The , abbreviated JMA, is an agency of the Ministry of Land, Infrastructure, Transport and Tourism. It is charged with gathering and providing results for the public in Japan that are obtained from data based on daily scientific observation an ...

(JMA) officially named this earthquake the . This earthquake occurred in the south of the inland of

Iwate Prefecture is a prefecture of Japan located in the Tōhoku region of Honshu. It is the second-largest Japanese prefecture at , with a population of 1,210,534 (as of October 1, 2020). Iwate Prefecture borders Aomori Prefecture to the north, Akita Prefectu ...

at 8:43 JST on June 14 (23:43 UTC on June 13). The JMA magnitude was estimated at 7.2, and the

moment magnitude The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 pape ...

USGS The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

was at 6.9. The

epicenter The epicenter, epicentre () or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Surface damage Before the instrumental pe ...

was located at , about 85 kilometres (55 mi) north of

Sendai is the capital city of Miyagi Prefecture, the largest city in the Tōhoku region. , the city had a population of 1,091,407 in 525,828 households, and is one of Japan's 20 designated cities. The city was founded in 1600 by the ''daimyō'' Date M ...

and about 385 kilometres (240 mi) north-northeast of Tokyo. The strongest shaking was measured in the cities of Ōshū (Iwate) and Kurihara (Miyagi), both of which were measured as "strong 6" on the

Japan Meteorological Agency seismic intensity scale The Japan Meteorological Agency (JMA) Seismic Intensity Scale (known in Japan as the Shindo seismic scale) is a seismic intensity scale used in Japan to categorize the intensity of local ground shaking caused by earthquakes. The JMA intensi ...

, .

Peak ground acceleration Peak ground acceleration (PGA) is equal to the maximum ground acceleration that occurred during earthquake shaking at a location. PGA is equal to the amplitude of the largest absolute acceleration recorded on an accelerogram at a site during a part ...

readings were high, with a maximum vector sum (3 component) value of 4,278 cm/s² (4.36g).

Intensity

represents the strength of

ground motion Ground motion is the movement of the earth's surface from earthquakes or explosions. Ground motion is produced by seismic waves that are generated by sudden slip on a fault or sudden pressure at the explosive source and travel through the earth ...

. JMA uses the scales o
0 to 7
0, 1, 2, 3, 4, weak/strong 5, weak/strong 6, 7. Tremors were felt across a large area.

Tectonics

According to the

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

The Mw 6.8 Honshu earthquake of June 13th 2008 occurred in a region of convergence between the Pacific Plate and the Okhotsk section of the North American Plate in northern Japan, where the Pacific plate is moving west-northwest with respect to North America at a rate of approximately 8.3 cm/yr. The hypocenter of the earthquake indicates shallow thrusting motion in the upper (Okhotsk) plate, above the subducting Pacific plate, which lies at approximately 80 km depth at this location.

The earthquake occurred in a region of upper-plate contraction, probably within the complicated tectonics of the Ou Backbone Range, known to have hosted several large earthquakes in historic times. The largest of these events occurred in 1896, approximately 70km north of the June 13th event, and killed over 200 people in the local area.

Aftershocks

According to JMA:As of 2008-07-02 ( 5:00 JST). Aftershocks of this earthquake were stronger than the

Great Hanshin earthquake The , or Kobe earthquake, occurred on January 17, 1995, at 05:46:53 JST (January 16 at 20:46:53 UTC) in the southern part of Hyōgo Prefecture, Japan, including the region known as Hanshin. It measured 6.9 on the moment magnitude scale and h ...

in 1995, but they happened much less frequently. Over 200 aftershocks were observed in the first 24 hours, with about 400 in total over the first seven days. The largest ones (with M_j5.0 or greater) were :June 14, 9:20: M_j5.7: Max. seismic intensity reached Strong 5; :June 14, 12:27: M_j5.2: Max. seismic intensity reached 4; :June 16, 23:14: M_j5.3: Max. seismic intensity reached 4. From June 21 to July 1, four to 12 aftershocks were observed each day, with maximum seismic intensities of 3.

Effects

Landslides

Landslides triggered by this earthquake crushed structures, buried people, cut off access to certain roads, and isolated some rural communities. Mud from landslides dammed up rivers to form lakes called . By June 19, the Ministry of Land had identified fifteen quake lakes in Iwate and Miyagi prefectures, and work crews began draining three of them which were at high risk of overflow or breach from rain or aftershocks.

Human casualties

By 17:50 JST, June 25, twelve people were confirmed dead and 358 injured, and ten still missing.As of 2008-06-25 (17:50 JST). * In the city of Kurihara, Miyagi Pref., five people were buried in a landslide at a hot-spring inn called ''Komanoyu'', which had stood on the mountainside of Mt. Kurikoma. A woman aged 80 who had co-managed the inn with her husband, her 58-year-old son, a woman aged 75 who had worked at the inn, a 48-year-old tourism consultant, and an attendant of the

Railway Museum A railway museum is a museum that explores the history of all aspects of rail related transportation, including: locomotives (steam, diesel, and electric), railway cars, trams, and railway signalling equipment. They may also operate historic ...

aged 35 were all killed in the landslide. * In the city of Kurihara, along Route 398, a landslide overwhelmed and killed three workers setting a rockfall containment net on a hillside. * Also in the city of Kurihara, along Route 398, a 59-year-old man was killed when his car was carried away by a landslide and buried. * At a dam construction site in the city of Ōshū, Iwate Pref., a worker aged 48 was struck by falling rocks and died. * In the city of Ichinoseki, Iwate Pref., a person surprised by the tremor ran out into the road and was fatally struck by a truck. * In the city of Iwaki, Fukushima Pref., near a fishing port, a person aged 55 was struck by falling rocks while fishing, fell into the sea, and drowned. * In the city of Ōshū, a landslide caused a group of 20 people to become temporarily trapped in an overturned bus. Eight of them were injured, including one critically and five seriously.Last updated on 2008-06-14 (21:04 JST). The bus was running when overturned, and ten passengers escaped, prompted by the driver. Then an aftershock caused the bus to slip down slowly into a ravine until it was caught on some trees. One of the passengers who had escaped walked down the road with a mobile phone until he was able to get a signal, and made an emergency call.

Electric power supply

No nuclear power plants were shut down following this earthquakeAs of 2008-06-14 (17:00 JST). unlike the

2007 Chūetsu offshore earthquake The ) was a powerful magnitude 6.6 earthquake that occurred 10:13 local time (01:13 UTC) on July 16, 2007, in the northwest Niigata region of Japan. The earthquake, which occurred at a previously unknown offshore fault shook Niigata and ne ...

quake. Some water was found to have splashed out of a reaction container in the

Fukushima II Nuclear Power Plant The is a nuclear power plant located on a site in the town of Naraha and Tomioka in the Futaba District of Fukushima Prefecture, Japan. The Tokyo Electric Power Company (TEPCO) runs the plant. After the 2011 Tōhoku earthquake and tsunami ...

possibly due to the tremor, but no radioactive material was released to the environment.

Expressways and railways

Expressways in

were closed in several sections, but all reopened by nighttime, barring traffic restrictions in one section for repair work. Some train services by

JR East The is a major passenger railway company in Japan and is the largest of the seven Japan Railways Group companies. The company name is officially abbreviated as JR-EAST or JR East in English, and as in Japanese. The company's headquarters ar ...

were suspended on

Shinkansen The , colloquially known in English as the bullet train, is a network of high-speed railway lines in Japan. Initially, it was built to connect distant Japanese regions with Tokyo, the capital, to aid economic growth and development. Beyond ...

and local lines, and resumed on the following day from the first scheduled trains.Last updated on 2008-06-15 (21:05 JST). On

Tōhoku Shinkansen The is a Japanese high-speed Shinkansen rail line, connecting Tokyo with Aomori in Aomori Prefecture in a route length of , making it Japan's longest Shinkansen line. It runs through the more sparsely populated Tōhoku region of Japan's main ...

, all running trains, about 20, were stopped by an earthquake detection system. Most were soon moved to the nearest stations. However, about 2,000 passengers were temporarily trapped inside three trains before being evacuated up to nine and a half hours later,Last updated on 2008-06-15 (0:27 JST). because the trains were forced to stay in place while equipment inspections were carried out. Suspensions on Tōhoku, Akita,

Yamagata Shinkansen The is a Mini-shinkansen route in Japan, operated by East Japan Railway Company (JR East). It provides service between Tokyo and Shinjō in Yamagata Prefecture over the tracks of the Tohoku Shinkansen and the Ōu Main Line. The term Yamagat ...

and delays on Jōetsu, Nagano Shinkansen reportedly involved 117,000 passengers. No trains derailed.

References

External links

* {{DEFAULTSORT:Iwate Earthquake 2008 earthquakes 2008 Iwate–Miyagi Nairiku earthquake Tōhoku region June 2008 events in Japan 2008 disasters in Japan