February 18, 1911 Earthquake: Usoy, Barchidiv, Posor, Nisur, Tajikistan

Reference #223 lists earthquake on Feb 18, 1911, 18:41:14 UTC, 38.2 N, 72.8 E, magnitude 7.4, intensity 9, depth 26 km:

"A terrifying mountainslide to the valley of the Bartang River near the Usoy kishlak occurred as result of strong tremors. This kishlak was destroyed. A whole sector of the mountain (60 degrees) immediately collapsed from the intense tremors. The collapsing mass of debris covered up to 16 square versts (1 verst = 3500 ft), and formed a giant dam with an embankment having a thickness of 4 to 5 km and a height of 703 to 788 m. The area of greatest destruction encompassed the Usoy, Barchidiv, Posor, Nisur (Nusur), Sagnob, Rukhch, Basid, and Oroshor kishlaks, where many buildings were destroyed and about 90 people and numerous cattle perished."

The maximum intensity of the earthquake is rated at 9. The magnitude has been reevaluated using instrumental data.

(above from reference #223)

Reference #1212 lists earthquake on Feb 18, 1911, 40 N, 73 E, magnitude 7.8.

Reference #130 lists earthquake on Feb 18, 1911, 18:41:03 UTC, 40 N, 73 E, magnitude 7.75, depth 48 km.

Reference #88 lists earthquake on Feb 18, 1911, 18:41:03 UTC, 40 N, 73 E, magnitude 7.75, shallow depth.

Reference #10476 (v.10) 1911 Feb 18 18:41:09.43 UTC, 38.289 N 72.596 E, 15 km depth, 7.23 Mw

Reference #9910 1911 Feb 18 18:41:03 UTC, 40 N 73 E, 7.2 Mw

Reference #13726:

During the period between 14 May and 3 June 1911 intelligence reports reaching British Agencies in Persia confirmed that 90 lives and a number of livestock had been lost in the 18 February earthquake (IO4). Other reports from Khorug confirmed that because of the fall of rocks, communications between Rushon (Kala-i-Vomar) and Roshorv (Oroshar) were completely interrupted and that the villages of Basid, Oroshar, Pasor (Agats Kurgan), and Nisir were almost totally destroyed (IO5).

News in the Petrograd press in mid-1911 confirmed that the Murghab River was dammed by a rockslide caused by an earthquake. In October 1911 the rising waters of the lake had started flooding the village of Sarez and other villages. It was not until the end of 1911 that the full picture of the effects of the earthquake became known in Petrograd, including the news that the natural dam across the Murghab River was likely to collapse when the lake behind it was impounded.

Along the Bartang River to the south, in the scattered homesteads of Pasor (Agatskurgan), which were occupied by herdsmen, five men, 16 women, and nine children were killed by the collapse of mud/stone dwellings. Further down the river at Bartchadiv the number of fatalities is not known, but in nearby Nisor, 17 men, 14 women, and nine children were killed through building collapse. At Sagnob (Saunab or Tashkurgan), six women and four children lost their lives, and at Rukhch (Karakurgan), two men and two women were killed. The largest number of fatalities was in the large village of Roshorv (Oroshar), where the death toll was 45 men, 58 women, and 77 children. Basid was almost totally ruined but with no casualties.

In Shpilko’s account, the total loss of life caused by both the earthquake and the landslides amounted to 302 men, women, and children. Our estimate is 318 […]

We deduce that the 18 February 1911 Usoy landslide was triggered by an earthquake with magnitude Mw = 7.7 ± 0.2 in the shallow crust beneath the Pamir near 38.3°N, 72.30°E.