Today in Earthquake History

On July 21st...

• M5.6 - Gansu, China, 1995

  Fourteen people killed, at least 60 injured, 5,000 left homeless, 4,500 houses destroyed and 5,000 houses damaged in the Yongdeng area. Felt at Baiyin, Dingxi, Jingtai, Lanzhou, Tianzhu and Wuwei. Also felt at Xining, Qinghai.

• M6.4 - Central California-Nevada Border, 1986

  About 20 mobile homes were damaged and a number of others shaken off their foundations in the Chalfant Valley, California. Several buildings were damaged (VI) at Bishop, California. Landslides occurred in the area. Fault rupture, maximum of 5 cm. of right-lateral slip, occurred along faults in the Volcanic Tableland west of Chalfant Valley and the White Mountains fault zone. The earthquake was felt throughout a large area of California and Nevada from San Francisco to Reno and south to Los Angeles and Las Vegas. Felt in high-rise buildings as far away as Salt Lake City, Utah. Depth 8.9 km. from broadband displacement seismograms.

• M5.6 - Arizona - Utah Border, 1959

  The largest historical earthquake in Arizona. Minor damage to chimneys and walls was reported at Fredonia, Arizona, and Kanab, Utah, about 15 kilometers north of Fredonia. In addition, windows broke in houses and stores and dishes fell from shelves at Fredonia. Almost all mechandise was shaken from shelves in stores. A rockslide at Mather Point in the Grand Canyon was attributed to the shock.

• M7.3 - Kern County, California (near Grapevine), 1952

  One of the largest earthquakes in the United States. This earthquake was the largest in the conterminous United States since the San Francisco shock of 1906. It claimed 12 lives and caused property damage estimated at $60 million. MM intensity XI was assigned to a small area on the Southern Pacific Railroad southeast of Bealville. There, the earthquake cracked reinforced-concrete tunnels having walls 46 centimeters thick; it shortened the distance between portals of two tunnels about 2.5 meters and bent the rails into S-shaped curves. At Owens Lake (about 160 kilometers from the epicenter), salt beds shifted, and brine lines were bent into S-shapes.

• M - Greece - Crete - Knossos, 365

  This earthquake affected the eastern Mediterranean region, including Italy, Greece, Palestine, and North Africa. Coastal towns in the region were leveled and a tsunami destroyed the Egyptian port of Alexandria, and the lighthouse for which the city was famous. Some 50,000 people are thought to have been killed.