2009 Serika earthquake

The 2009 Serika earthquake (芹香川地震) occurred with a magnitude of 7.1 moment magnitude scale struck in northwestern part of Serika Metropolis. The earthquake's epicenter was around Serikagawa ward and occurred at a depth of 292.0.

Shaking from the earthquake was felt strongly in the metropolis prefecture and the surrounding metropolitan areas including Mizawa and Shimazaki, temporarily disrupting electrical and gas service to 860,000 homes and buildings. The earthquake hit in the late rush hour disrupting train services for several hours, and also damaged water pipes and hundreds of homes.

Earthquake
The August 9, 2009, M 7.1 earthquake occurred as the result of deep oblique-reverse faulting, approximately 300 km beneath the Pacific Ocean in Nakama, within the Izu-Bonin subduction system. Focal mechanism solutions indicate that rupture occurred on either a near-vertical reverse fault or a shallowly dipping thrust fault. The earthquake occurred at depth within the westward-dipping Pacific plate, well beneath the overriding Philippine Sea plate.

The earthquake triggered the national earthquake warning system, which set alarms approximately 3.2 seconds for the Serika and Mizawa areas after the detection of seismic waves. No tsunami waves were generated as a result of the earthquake.

Damage and effects
The earthquake caused the partial collapse of several buildings, as well as damage to underground water pipes that left residents without running water. A total of 11,827 structures were found by government surveys to have sustained partial damage, primarily in Serika and Shimazaki Prefecture. As many as 720 people remained in public shelters a week after the earthquake. Roof tiles and stone ornaments at homes and historic temples and shrines fell to the ground. At least 860,000 homes in Serika were initially under an electrical blackout, but power was restored later in the morning. The earthquake disrupted train services, including the Shinkansen, during the evening rush hour but had resumed in the morning after.

Soil liquefaction was evident in areas of reclaimed land around Serika. Approximately 30 homes or buildings were destroyed and 1,046 other buildings were damaged to varying degrees.

Casualties
There have been four confirmed deaths resulting from the earthquake, 62 people have also been injured and treated at hospitals.