1902 Turkestan earthquake
The 1902 Turkestan earthquake (; ; ), also known as the Kashgar earthquake (; ; ), Atushi earthquake, and Artux earthquake, was a devastating seismic event that struck the western part of Xinjiang, an autonomous territory in China, near the border with Kyrgyzstan. It occurred on August 22, 1902, at about 8:00 or 9:00 am local time. An estimated 5,650–10,000 people were killed, with many more injured. The earthquake measured 7.7 on the moment magnitude scale. Tectonic setting. The geological forces at play around Kyrgyzstan and Xinjiang are directly related to the ongoing collision of the Indian Plate with the Eurasian Plate. The  topography of this region is influenced by broad crustal deformation as a result of convergence along the Main Himalayan Thrust. Before the Indian subcontinent collided with Eurasia, there were island arcs and microcontinents between the two landmasses that were also converging. These terranes were later accreted to Eurasia as northward-moving India closed collided with Eurasia, and are now in present-day Central Asia. Ancient suture zones mark the boundary between these accreted terranes. This deformation and accretion led to the formation of the Tien Shan mountains, which are moving 7±2 mm/yr towards the south along faults running along  their base. The region is dominated by large, north and south-dipping thrust faults along the southern edge of the Tien Shan mountains, and the northern boundary of the Tarim basin, one of them being the Aheqi Fault Zone. Earthquake. While scientific knowledge of the event is rather sparse due to the period in which it happened, research has given new insights into the earthquake of August 22, 1902. In a 2017 research, the earthquake was determined to have occurred at a depth of 18 km, while the epicenter coordinates at 39.87° N 76.42° E, a relocation from  most global event catalogs that place the epicenter coordinates at 40.0° N 77.00° E. The earthquake magnitude was also recalculated to be 7.7, while older figures presented magnitude 8.25 or 8.6. Past studies have suggested a focal depth of 40 km based on the large area felt with intensity X on the Rossi–Forel scale. It is the largest and earliest recorded earthquake in the Tien Shan region. An aftershock of 6.8 occurred eight days later. A series of magnitude 6.0 or greater earthquakes follow in the years after the event. Characteristics. Thrust faulting was the cause of  this event, involving a rupture on the Ttiotegongbaizi-Aerpaleike Fault located at the southern flanks of the Tien Shan range. Analysis show that the quake was consistent with a rupture involving the Tuotegongbaizi-Aerpaleike Fault, near the western segment of the much larger Kalpin fold and thrust belt. The fault is 200 km long, and has a surface fault trace like a gentle wave-shape. It dips to the north at varying angles of 25° to 60°. Field observations by researchers found no trace of surface ruptures indicating the event was a blind thrust earthquake. The same fault  system was responsible for the 1996 Artux earthquake, an 6.3 event that killed some 26 people in March 1996. Damage and casualties. The earthquake struck at 8:00 or 9:00 am on August 22, lasting for one and a half minutes, and reported to be extremely violent. Severe aftershocks were felt every day up till August 30. The mainshock was recorded on seismographs all over Europe. It had a maximum intensity of X on the Modified Mercalli, Rossi–Forel, and Medvedev–Sponheuer–Karnik scales. Around the meizoseismal area; an area that encompassed Kashgar and Artux, shaking was assigned X on the  Rossi–Forel intensity scale for 150 km in the east–west direction in the southern base of the Tien Shan. The ground motion was so forceful that the tip of trees touched the ground and some were even uprooted or snapped. All wood-constructed homes collapsed and many tents became deformed. Ground slumping near a riverbank blocked roads and dammed streams. Large ground fissures ejected water, transforming the ground into mud. The largest fissure measured one kilometer in length, several meters wide, and three meters deep. Five hundred (500) people died in the area. Many domesticated animals were also killed . In Kashgar, the mainshock collapsed sun-dried brick walls and collapsing homes. Masonry buildings however did not sustain serious damage. Numerous fissures opened in the northern entrance of the city, where the city walls also toppled. Part of the Afaq Khoja Mausoleum, a tomb in the heart of Kashgar, collapsed and fractured. At least 50 inhabitants lost their lives or were injured. The Artush district north of Kashgar suffered more devastating consequences. The earthquake collapsed almost every house in the area. Some 667 people were killed, and thousands more were injured in the city. The village of Astyn saw 400  fatalities, and in Jangi, 20 fatalities. In Yarkand, there was less serious damage to the city, but two children lost their lives due to collapsing walls. There was also damage reported in Narin and Atbashi although no residents were killed.