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|duration = 45 seconds–1 minute 〔 |magnitude = 7.3 MW 〔〔 |depth = |location = 〔 |type = Oblique-slip |countries affected = Southern California United States |damage = $70 million 〔〔 |intensity = XI (''Extreme'') 〔 |PGA = ~ 1''g'' (est) |casualties = 14 killed 〔〔 Hundreds injured 〔 }} The 1952 Kern County earthquake occurred on July 21 in the southern San Joaquin Valley and measured 7.3 on the moment magnitude scale. The main shock occurred at 4:52 am Pacific Daylight Time (11:52 UTC), killed 12 people and injured 18, and caused an estimated $60 million in property damage. A small sector of damage near Bealville corresponded to a maximum Mercalli intensity of XI (''Extreme''), though this intensity rating was not representative of the majority of damage. The earthquake occurred on the White Wolf Fault near the community of Wheeler Ridge and was the strongest to occur in California since the 1906 San Francisco earthquake. The town of Tehachapi suffered the greatest damage and loss of life from the earthquake, though other locations in Kern County experienced significant damage as well, but its effects were widely felt throughout central and southern California. The July mainshock had a significant aftershock sequence that persisted into July and August with many magnitude 5+ events with intensities of V (''Moderate'') to VII (''Very Strong''). Six of these aftershocks occurred on the day of the mainshock, but the strongest aftershock came on August 22 as a M5.8 event that had a maximum perceived intensity of VIII (''Severe'') and resulted in the deaths of two people and caused an additional $10 million in property damage. Following the event, a field survey was conducted along the fault zone with the goal of estimating the peak ground acceleration of the shock based on visually evaluating precarious rock formations and other indicators. Ground disturbances that were created by the earthquakes were also surveyed, both in the valley and in the foothills, with both vertical and horizontal displacements present in the epicentral area. The strong motion records that were acquired from the event were significant, and a reconnaissance report was recognized for its coverage of the event, and how it set a standard for those types of engineering or scientific papers. Repercussions of the sequence of earthquakes were still being felt in the heavily damaged downtown area of Bakersfield well into the 1990s as city leaders attempted to improve safety of the surviving unreinforced masonry buildings. ==Tectonic setting== At Lebec, California, just south of the epicenter of the July mainshock, the San Andreas Fault comes together with the Garlock Fault, which is positioned at the northern border of the Mojave Desert. The San Andreas has been responsible for considerable seismic activity at its northern and southern sections, and traverses the area near the Transverse Ranges. The Kern Canyon Fault mirrors the path of the Kern River, and was thought to have a connection with the White Wolf Fault, but indicators observed following the July 21 earthquake demonstrated that the two are offset. The Owens Valley Fault, on the east side of the Sierran block, has been mapped and may possibly extend into area that was affected by the 1952 shocks. Other fault zones are present in the region, and have been of interest because they may have been responsible for minor earthquakes, but they are considered not as significant as the Kern Canyon, Owens Valley, and San Andreas Faults. The 1952 earthquakes were the first to be observed well within Kern County lines. Other strong, but remote events were previously felt in the area, but they were distant enough to cause only occasional destructive effects. The county is bounded on the western side by the Temblor Range which is adjacent to the southern San Andreas Fault. Other large events have affected the area as well, like the January 1857 Fort Tejon earthquake that severely affected Fort Tejon (about south of Wheeler Ridge). 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「1952 Kern County earthquake」の詳細全文を読む スポンサード リンク
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