|
|mapsize = |caption = |date = |origintime = 21:35 PST |duration = |magnitude = 6.9 Mw |depth = 〔 |location = 〔 |type = Strike-slip |countries affected = United States, Mexico |damage = $ 6 million 〔 |intensity = X (''Extreme'') 〔 |PGA = |tsunami = |landslide = |foreshocks = |aftershocks = |casualties = 9 〔 }} The 1940 El Centro earthquake (or 1940 Imperial Valley earthquake) occurred at 21:35 Pacific Standard Time on May 18 (05:35 UTC on May 19) in the Imperial Valley in southeastern Southern California near the international border of the United States and Mexico. It had a moment magnitude of 6.9 and a maximum perceived intensity of X (''Extreme'') on the Mercalli intensity scale. It was the first major earthquake to be recorded by a strong-motion seismograph located next to a fault rupture. The earthquake was characterized as a typical moderate-sized destructive event with a complex energy release signature. It was the strongest recorded earthquake to hit the Imperial Valley, and caused widespread damage to irrigation systems and led to the deaths of nine people.〔 ==Tectonic setting== The Salton Trough is part of the complex plate boundary between the Pacific Plate and the North American Plate where it undergoes a transition from the continental transform of the San Andreas Fault system to the series of short spreading centers of the East Pacific Rise linked by oceanic transforms in the Gulf of California. The two main right lateral strike-slip fault strands that extend across the southern part of the trough are the Elsinore Fault Zone/Laguna Salada Fault to the western side of the trough and the Imperial Fault to the east. The Imperial Fault is linked to the San Andreas Fault through the Brawley Seismic Zone, which is a spreading center beneath the southern end of the Salton Sea. With the San Jacinto Fault Zone to the west, the Elsinore fault to the south-southwest, and the Imperial fault centered directly under the Imperial Valley, the area frequently encounters seismic activity, including moderate and damaging earthquakes. Other events in 1852, 1892, 1915, 1942, 1979, and 1987 have impacted the region in varying degrees. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「1940 El Centro earthquake」の詳細全文を読む スポンサード リンク
|