2008 Iwate-Miyagi Nairiku earthquake
Encyclopedia
The 2008 Iwate earthquake on June 14, 2008 mainly struck mid Tōhoku region
, northeastern Honshū
, Japan. Japan Meteorological Agency
(JMA) officially named this earthquake .
This earthquake occurred in the south of the inland of Iwate Prefecture
at 8:43 JST
on Saturday morning, June 14 (23:43 UTC
on June 13). The JMA magnitude was estimated at Mj 7.2, and
the moment magnitude
by USGS
was at Mw 6.9. The epicenter
was located at 39°01.7′N 140°52.8′E, about 85 kilometres (55 mi) north of Sendai and about 385 kilometres (240 mi) north-northeast of Tokyo.
The strongest shakings were 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
, . Peak ground acceleration
readings were high, with a maximum vector sum (3 component) value of 4278 cm/s2 (4.36g).
Tremors were felt across a large area.
Strongly shaken areas included:
Strong 6:
Weak 6:
Strong 5:
Aftershocks of this earthquake were stronger than the Great Hanshin Earthquake
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 Mj5.0 or greater) were
From June 21 to July 1, four to 12 aftershocks were observed each day, with maximum seismic intensities of 3.
that occurred in the five days following the 2008 Iwate earthquake. Aftershocks measured 6.0 Mw or over are in bold.
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.
quake. Some water was found to have splashed out of a reaction container in the Fukushima II Nuclear Power Plant
possibly due to the tremor, but no radioactive material was released to the environment.
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
were suspended on Shinkansen
and local lines, and resumed on the following day from the first scheduled trains.
On Tōhoku Shinkansen
, 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, because the trains were forced to stay in place while equipment inspections were carried out.
Suspensions on Tōhoku, Akita
, Yamagata Shinkansen
and delays on Jōetsu
, Nagano
Shinkansen reportedly involved 117,000 passengers. No trains derailed.
Tohoku region
The is a geographical area of Japan. The region occupies the northeastern portion of Honshu, the largest island of Japan. The region consists of six prefectures : Akita, Aomori, Fukushima, Iwate, Miyagi and Yamagata....
, northeastern Honshū
Honshu
is the largest island of Japan. The nation's main island, it is south of Hokkaido across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyushu across the Kanmon Strait...
, Japan. Japan Meteorological Agency
Japan Meteorological Agency
The or JMA, is the Japanese government's weather service. Charged with gathering and reporting weather data and forecasts in Japan, it is a semi-autonomous part of the Ministry of Land, Infrastructure and Transport...
(JMA) officially named this earthquake .
This earthquake occurred in the south of the inland of Iwate Prefecture
Iwate Prefecture
is the second largest prefecture of Japan after Hokkaido. It is located in the Tōhoku region of Honshū island and contains the island's easternmost point. The capital is Morioka. Iwate has the lowest population density of any prefecture outside Hokkaido...
at 8:43 JST
Japan Standard Time
Japan Standard Time or JST is the standard timezone of Japan, and is 9 hours ahead of UTC. For example, when it is midnight in UTC, it is 09:00 in Japan Standard Time. There is no daylight saving time, though its introduction has been debated several times. Japan Standard Time is the same as...
on Saturday morning, June 14 (23:43 UTC
Coordinated Universal Time
Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...
on June 13). The JMA magnitude was estimated at Mj 7.2, and
the moment magnitude
Moment magnitude scale
The moment magnitude scale is used by seismologists to measure the size of earthquakes in terms of the energy released. The magnitude is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of...
by USGS
United States Geological Survey
The United States 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, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...
was at Mw 6.9. The epicenter
Epicenter
The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates...
was located at 39°01.7′N 140°52.8′E, about 85 kilometres (55 mi) north of Sendai and about 385 kilometres (240 mi) north-northeast of Tokyo.
The strongest shakings were measured in the cities of Ōshū
Oshu, Iwate
is the second largest city in Iwate Prefecture, Japan with a population of 127,804.The city was founded on February 20, 2006, as the result of a merger between the cities of Esashi and Mizusawa, the towns of Maesawa and Isawa and the village of Koromogawa from Isawa District...
(Iwate) and Kurihara
Kurihara, Miyagi
is a city located in Miyagi Prefecture, Japan. As of 2008, the city has an estimated population of 77,012 and a population density of 95.7 persons per km². The total area is 804.93 km². Previously a district consisting of nine towns and one village, on April 1, 2005, the towns and village...
(Miyagi), both of which were measured as "strong 6" on the Japan Meteorological Agency seismic intensity scale
Japan Meteorological Agency seismic intensity scale
The Japan Meteorological Agency seismic intensity scale is a seismic scale used in Japan and Taiwan to measure the intensity of earthquakes. It is measured in units of...
, . Peak ground acceleration
Peak ground acceleration
Peak ground acceleration is a measure of earthquake acceleration on the ground and an important input parameter for earthquake engineering, also known as the design basis earthquake ground motion...
readings were high, with a maximum vector sum (3 component) value of 4278 cm/s2 (4.36g).
Seismic intensity
represents the strength of ground motion. JMA uses the scales of 0 to 7: 0, 1, 2, 3, 4, weak/strong 5, weak/strong 6, 7.| Prefecture | |Seismic intensities | |||||||
|---|---|---|---|---|---|---|---|---|
| Iwate | 6+ | 6- | 5+ | 5- | 4 | 3 | 2 | |
| Miyagi | 6+ | 6- | 5+ | 5- | 4 | 3 | ||
| Akita | 5+ | 5- | 4 | 3 | 2 | |||
| Yamagata | 5- | 4 | 3 | 2 | ||||
| Fukushima | 5- | 4 | 3 | 2 | 1 | |||
| Aomori | 4 | 3 | 2 | 1 | ||||
| Ibaraki | 4 | 3 | 2 | |||||
| Tochigi | 4 | 3 | 2 | 1 | ||||
| Niigata | 4 | 3 | 2 | 1 | ||||
| Hokkaidō | 3 | 2 | 1 | |||||
| Gunma | 3 | 2 | 1 | |||||
| Saitama | 3 | 2 | 1 | |||||
| Chiba | 3 | 2 | 1 | |||||
| Tokyo | 3 | 2 | 1 | |||||
| Kanagawa | 3 | 2 | 1 | |||||
| Yamanashi | 3 | 2 | 1 | |||||
| Ishikawa | 2 | 1 | ||||||
| Nagano | 2 | 1 | ||||||
| Shizuoka | 2 | 1 | ||||||
| Aichi | 1 |
Tremors were felt across a large area.
Strongly shaken areas included:
Strong 6:
- Iwate Pref. - City of Ōshū (奥州市).
- Miyagi Pref. - City of Kurihara (栗原市).
Weak 6:
- Iwate Pref. - City of Ōshū (奥州市).
- Miyagi Pref. - Cities of Kurihara (栗原市) and Ōsaki (大崎市).
Strong 5:
- Iwate Pref. - Cities of Ōshū (奥州市), Kitakami (北上市), Ichinoseki (一関市), Towns of Kanegasaki (金ケ崎町) and Hiraizumi (平泉町).
- Miyagi Pref. - Cities of Kurihara (栗原市), Ōsaki (大崎市), Sendai (仙台市), Tome (登米市), Natori (名取市), Towns of Misato (美里町), Wakuya (涌谷町), Kami (加美町), and Rifu (利府町).
- Akita Pref. - City of Yuzawa (湯沢市), and Village of Higashinaruse (東成瀬村).
Tectonics
According to the USGS: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:Aftershocks of this earthquake were stronger than the Great Hanshin Earthquake
Great Hanshin earthquake
The Great Hanshin earthquake, or Kobe earthquake, was an earthquake that occurred on Tuesday, January 17, 1995, at 05:46 JST in the southern part of Hyōgo Prefecture, Japan. It measured 6.8 on the moment magnitude scale , and Mj7.3 on JMA magnitude scale. The tremors lasted for approximately 20...
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 Mj5.0 or greater) were
- June 14, 9:20: Mj5.7: Max. seismic intensity reached Strong 5;
- June 14, 12:27: Mj5.2: Max. seismic intensity reached 4;
- June 16, 23:14: Mj5.3: 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.
Subsequent earthquakes
The following is a list of earthquakes greater than 4.0 MwMoment magnitude scale
The moment magnitude scale is used by seismologists to measure the size of earthquakes in terms of the energy released. The magnitude is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of...
that occurred in the five days following the 2008 Iwate earthquake. Aftershocks measured 6.0 Mw or over are in bold.
| # | Date | Time | Place | Lat. | Long. | Fatalities | Mw Moment magnitude scale The moment magnitude scale is used by seismologists to measure the size of earthquakes in terms of the energy released. The magnitude is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of... |
|---|---|---|---|---|---|---|---|
| June 13 | |||||||
| Magnitude 6.9 - EASTERN HONSHU, JAPAN | June 13, 2008 | 23:43:46 UTC | Honshū Honshu is the largest island of Japan. The nation's main island, it is south of Hokkaido across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyushu across the Kanmon Strait... , Japan (main earthquake) |
39.103 | 140.668 | 10 + (12 missing) | 6.9 |
| June 14 | |||||||
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgah.php | June 14, 2008 | 00:20:13 UTC | Honshū, Japan | 38.991 | 140.461 | 5.5 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgam.php | June 14, 2008 | 00:52:43 UTC | Honshū, Japan | 39.139 | 140.792 | 4.7 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgan.php | June 14, 2008 | 01:00:16 UTC | Honshū, Japan | 39.087 | 140.770 | 4.6 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgas.php | June 14, 2008 | 01:39:48 UTC | Honshū, Japan | 39.107 | 140.819 | 4.7 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgau.php | June 14, 2008 | 02:35:17 UTC | Honshū, Japan | 39.039 | 140.698 | 4.6 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgax.php | June 14, 2008 | 03:10:32 UTC | Honshū, Japan | 39.145 | 140.736 | 4.8 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgaz.php | June 14, 2008 | 03:14:05 UTC | Honshū, Japan | 39.023 | 140.757 | 4.6 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tga1.php | June 14, 2008 | 03:27:34 UTC | Honshū, Japan | 39.255 | 140.710 | 5.0 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tga6.php | June 14, 2008 | 04:10:48 UTC | Honshū, Japan | 39.127 | 140.684 | 4.6 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tga8.php | June 14, 2008 | 05:39:08 UTC | Honshū, Japan | 39.320 | 140.727 | 4.5 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgbg.php | June 14, 2008 | 08:34:10 UTC | Honshū, Japan | 39.172 | 140.790 | 4.5 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgbi.php | June 14, 2008 | 10:11:57 UTC | Honshū, Japan | 38.907 | 140.707 | 4.5 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgbn.php | June 14, 2008 | 12:48:30 UTC | Honshū, Japan | 39.284 | 140.625 | 4.7 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgb2.php | June 14, 2008 | 14:42:33 UTC | Honshū, Japan | 39.092 | 140.745 | 5.1 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgc2.php | June 14, 2008 | 17:29:27 UTC | Honshū, Japan | 39.118 | 140.881 | 4.4 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgc1.php | June 14, 2008 | 18:29:22 UTC | Honshū, Japan | 39.221 | 140.739 | 4.5 | |
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tgcz.php | June 14, 2008 | 18:47:37 UTC | Honshū, Japan | 39.218 | 140.781 | 4.6 | |
| June 15 | |||||||
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008thas.php | June 15, 2008 | 03:30:02 UTC | Honshū, Japan | 39.168 | 140.870 | 4.6 | |
| June 16 | |||||||
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tiaw.php | June 16, 2008 | 14:14:39 UTC | Honshū, Japan | 39.084 | 140.607 | 5.1 | |
| June 18 | |||||||
| http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008tka1.php | June 18, 2008 | 09:04:34 UTC | Honshū, Japan | 39.156 | 140.863 | 4.8 | |
| Sources: | |||||||
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
Ministry of Land, Infrastructure and Transport (Japan)
The , abbreviated MLIT, is a ministry of the Japanese government. It is responsible for one-third of all the laws and orders in Japan and the largest Japanese ministry in terms of employees, as well as the second-largest organ of the Japanese government after the Ministry of Defense...
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.- In 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 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. 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 earthquake unlike the 2007 Chūetsu offshore earthquake2007 Chuetsu offshore earthquake
The Chūetsu Offshore Earthquake was a powerful magnitude 6.6 earthquake that occurred 10:13 a.m. local time on July 16, 2007, in the northwest Niigata region of Japan. The earthquake shook Niigata and neighbouring prefectures...
quake. Some water was found to have splashed out of a reaction container in the Fukushima II Nuclear Power Plant
Fukushima II Nuclear Power Plant
The , or Fukushima Dai-ni , is a nuclear power plant located on a site in the town of Naraha and Tomioka in the Futaba District of Fukushima Prefecture, Japan...
possibly due to the tremor, but no radioactive material was released to the environment.
Expressways and railways
Expressways in Tōhoku regionTohoku region
The is a geographical area of Japan. The region occupies the northeastern portion of Honshu, the largest island of Japan. The region consists of six prefectures : Akita, Aomori, Fukushima, Iwate, Miyagi and Yamagata....
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
East Japan Railway Company
is the largest passenger railway company in the world and one of the seven Japan Railways Group companies. The company name is officially abbreviated as JR East in English, and as in Japanese. The company's headquarters are in Yoyogi, Shibuya, Tokyo....
were suspended on Shinkansen
Shinkansen
The , also known as THE BULLET TRAIN, is a network of high-speed railway lines in Japan operated by four Japan Railways Group companies. Starting with the Tōkaidō Shinkansen in 1964, the network has expanded to currently consist of of lines with maximum speeds of , of Mini-shinkansen with a...
and local lines, and resumed on the following day from the first scheduled trains.
On Tōhoku Shinkansen
Tohoku Shinkansen
The is a Japanese high-speed Shinkansen rail line, connecting Tokyo with Aomori in Aomori Prefecture for a total length of 674 km, Japan's longest Shinkansen line. It runs through the more sparsely populated Tōhoku region of Japan's main island Honshu. It has two spur lines, Yamagata...
, 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, because the trains were forced to stay in place while equipment inspections were carried out.
Suspensions on Tōhoku, Akita
Akita Shinkansen
The is a Mini-shinkansen high-speed rail line in Japan. Serving the Kantō and Tōhoku Regions of the country, it links Tokyo and Akita in Akita prefecture with direct service. From Tokyo to Morioka in Iwate prefecture, it operates on the Tōhoku Shinkansen tracks. From there to Ōmagari, it uses the...
, Yamagata Shinkansen
Yamagata Shinkansen
The is a Mini-shinkansen route in Japan, operated by East Japan Railway Company . It provides service between Tokyo and Shinjō in Yamagata Prefecture over the tracks of the Tōhoku Shinkansen and the Ōu Main Line....
and delays on Jōetsu
Joetsu Shinkansen
The is a high-speed railway line connecting Tokyo and Niigata, Japan, via the Tōhoku Shinkansen, operated by the East Japan Railway Company .-History:The program was initiated in 1971 by Niigata-born prime minister Tanaka Kakuei...
, Nagano
Hokuriku Shinkansen
The is a high-speed Shinkansen rail line under construction in Japan. The first section, between and , currently called the Nagano Shinkansen, opened on 1 October 1997.-Future:...
Shinkansen reportedly involved 117,000 passengers. No trains derailed.