2003 Hokkaido earthquake
Encyclopedia
The 2003 Hokkaidō earthquake (aka 2003 Tokachi-Oki Earthquake ) occurred on September 25, 2003 in Hokkaidō
, Japan
. It measured 8.3 on the Moment magnitude scale
and caused extensive damage, destroying roads all around Hokkaidō, and caused several power outages and further damaging landslides. A number of people were injured. The earthquake also caused a tsunami reaching 4 meters in height. The earthquake's presence was felt throughout Japan, stretching all the way to Honshu
and Tokyo
. The earthquake was the largest in 2003.
of this earthquake are consistent with it being a result of thrust fault
ing between the North American Plate
and the subducting Pacific plate
. In addition to experiencing large thrust earthquakes that originate on the interface between the plates, eastern Hokkaidō experiences great earthquakes that originate from the interior of the subducted Pacific plate.
, and one in 2008 measuring 7.1, all bearing the name Tokachi-Oki and a 1973 quake to the immediate north along the Kuril Trench plate boundary, called the 1973 Nemuro-Oki Earthquake.
Hokkaido
, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
. It measured 8.3 on the Moment magnitude scale
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...
and caused extensive damage, destroying roads all around Hokkaidō, and caused several power outages and further damaging landslides. A number of people were injured. The earthquake also caused a tsunami reaching 4 meters in height. The earthquake's presence was felt throughout Japan, stretching all the way to Honshu
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...
and Tokyo
Tokyo
, ; officially , is one of the 47 prefectures of Japan. Tokyo is the capital of Japan, the center of the Greater Tokyo Area, and the largest metropolitan area of Japan. It is the seat of the Japanese government and the Imperial Palace, and the home of the Japanese Imperial Family...
. The earthquake was the largest in 2003.
Tectonics
The location and moment tensor solutionFocal mechanism
The focal mechanism of an earthquake describes the inelastic deformation in the source region that generates the seismic waves. In the case of a fault-related event it refers to the orientation of the fault plane that slipped and the slip vector and is also known as a fault-plane solution...
of this earthquake are consistent with it being a result of thrust fault
Thrust fault
A thrust fault is a type of fault, or break in the Earth's crust across which there has been relative movement, in which rocks of lower stratigraphic position are pushed up and over higher strata. They are often recognized because they place older rocks above younger...
ing between the North American Plate
North American Plate
The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, Bahamas, and parts of Siberia, Japan and Iceland. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust...
and the subducting Pacific plate
Pacific Plate
The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million square kilometres, it is the largest tectonic plate....
. In addition to experiencing large thrust earthquakes that originate on the interface between the plates, eastern Hokkaidō experiences great earthquakes that originate from the interior of the subducted Pacific plate.
Damage
1 angler killed in tsunami. The earthquake caused great damage, causing power outages, landslides, and destroying several ocean side home communities. It was offshore, causing less damage than if under the city, and an estimated cost was not given.Regional seismicity
The region has been rocked by an catastrophic earthquake/tsunami of Magnitude 9 in 1667 A.D., a magnitude 8.2 in 1952, a 1968 quake measuring 8.3 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...
, and one in 2008 measuring 7.1, all bearing the name Tokachi-Oki and a 1973 quake to the immediate north along the Kuril Trench plate boundary, called the 1973 Nemuro-Oki Earthquake.