Bozqush Earthquake of 22 March 1879, Ms=6.7

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Bozqush Earthquake of 22 March 1879, Ms=6.7

The earthquake ruined many villages north of Miyaneh and killed more than 2000 people at the southern and eastern foothills of the Bozqush Mountains in northwest Iran. After finding a 2-km-long section exposure of a recent fault in the area about 1 km north of Sarighamish, located in the meizoseismal area of the earthquake, Berberian (1976c) reported that the fault could have been associated with the 1879 earthquake. The fault was described as a high-angle reverse fault with an approximate strike of N170E and dip of 75°SW. The southwestern block, which is composed of silicified allunite-bearing breccia of Miocene age, is thrust over the northeaster Quaternary alluvial deposits with a 3-m-thick gauge zone. The 1976 observed short section could be a part of a nearly N–S Germirud fault with a length of about 60 km. The 1879 event might have occurred on either the Germirud fault or the eastern section of the nearly E–W to NE–SW South Bozqush fault system, which also shows active escarpments. The NE–SW (N30°E) elongated meizoseismal area of the 1879 earthquake proposed by Ambraseys and Melville (1982) follows neither the South Bozqush nor the Germirud faults. An angle of 140° exists between the long axes of meizoseismal area and the reported azimuth of the faulting reported by Ambraseys and Melville (1982).  The case requires further field investigation and paleoseismic trench study along both faults. The seismic sequence in this region started with the 30 December 1863 M 6.1 earthquake along the northern segment of the Sangavar fault. Sixteen years later, seismicity migrated cross-fault to the southwest with the 1879 Ms6.7 SE Bozqush earthquake. Seventeen years later, the seismicity migrated to the east with the 4 January 1896 Ms6.7 earthquake along the southern segment of the Sangavar fault.

 Berberian, 2014_Page_236

The most important worldwide earthquakes (M>7) of this day

Date Time Y X Depth Mw Region Refrence
1879/3/22 – 37.80 47.90 6.7 Bozghosh Amb
1903/3/22 14:35:0 35 60 0 6.2 Derakhsh Amb
1928/3/22 4:17:05 16.142 -96.107 15 7.6 Oaxaca, Mexico USGS
1955/3/22 14:05:09 -9.101 91.653 20 7 South Indian Ocean USGS
1977/3/22 11:57:30 27.579 56.465 39 6  – NEIC