1905 Tsetserleg–Bulnay earthquakes

Mw 8+ earthquake sequence in Mongolia 1905 Tsetserleg–Bulnay earthquakes y 1905 7 09 y 1905 7 23 17:40:39 10:46:12 1905-07-09 09:40:39 1905-07-23 02:46:12 Mongolia Mongolia 49.71 98.48 Bullseye1.png 40 Tsetserleg right 250 right Mongolia 49.37 96.61 Bullseye1.png 40 Bulnay left 250 right Mongolia 47.9221 106.9155 Green pog.svg 100 bottom Ulaanbaatar 250 right 260 right yes s 7.9 y,Okal 1977 330 w 8.0 ySchlupp Cisternas 2007 1115l 8.4,Richter 1958 m 8.3-9.03Okal 1992 36 s 8.25 y,Okal 1977 330 w 8.3 yunk 8.4 y,Pollitz Vergnolle Calais 2003 16-1 w 8.3-8.5,Schlupp Cisternas 2007 1115 l 8.7,Richter 1958 m 8.33Okal 1992 36 15.0 km Northwestern Mongolia Mongolia 16957859 16957865 iscgem16957859 iscgem16957865 VIII The 1905 Tsetserleg–Bulnay earthquakes occurred in remote northwestern Mongolia in July 1905. The magnitude 7.9–8.0 Tsetserleg shock struck on July 9 near the Tsetserleg Sum of Khövsgöl Province. The magnitude 8.25-8.4 Bulnay earthquake hit 2 weeks later on July 23 near Asgat Sum, Zavkhan Province on 23 July. The Tsetserleg earthquake ruptured 190 km on of fault, while the Bulnay earthquake ruptured 455 km on. Geological effects from the earthquakes were widespread, and well documented. This earthquake sequence remains of scientific interest for two reasons: the sequence is the "largest continental strike-slip earthquake sequence ever documented", and the earthquakes started a cascade of triggered ruptures starting with each other, along with the 1931 Fuyun and 1957 Mongolia earthquakes. Tectonic setting The Bolnai fault system is a major left-lateral strike-slip fault system that runs east–west in Mongolia. It formed in reaction to the collision of the India plate with the Eurasia plate. The main fault segment of the Bolnai fault system is the Bolnai fault, which runs for 600 km on. The system slips at an average slip rate of around 3.1 mm/yr, and has previously ruptured in similar earthquakes 2.3-4.0 kyrkyr thousand years ago.Choi Klinger Ferry Ritz 2018 1927Rizza Ritz Prentice Vassallo 2015 72 These previous fault ruptures likely occur in a similar manner as this sequence, as the fault displacements are similar.Rizza Ritz Prentice Vassallo 2015 75, 90 Other major faults in the system include the Tsetserleg, Teregtiin, and Düngen faults. The Tsetserleg fault is a left-lateral strike-slip and reverse fault. The Teregtiin (also spelled Teregtyin and Teregtiyn) fault is a north-northwest trending dextral fault that splits off from the Bolnai fault. As it approaches the Bolnai fault, it has a reverse component, causing it to be an oblique fault in the area. The Düngen fault is a north–south trending (fault direction) dextral strike-slip fault that joins that runs perpendicularly from the Bolnai fault.Schlupp Cisternas 2007 1115–1116Rizza Ritz Prentice Vassallo 2015 74 Tsetserleg earthquake thumb|Map of 1905 Tsetserleg-Bulnay ruptures adapted from Choi et al. (2018) The Tsetserleg earthquake struck remote northwestern Mongolia near Tsetserleg Sum of Khövsgöl Province at 17:40 local time on July 9, 1905. The w 8.0 earthquake had a clear left-lateral strike-slip surface rupture along the Tsetserleg fault for 130 km on, with an additional 60 km on of rupture continuing northeastward and not breaking the surface.Schlupp Cisternas 2007 1115Choi Klinger Ferry Ritz 2018 1927 Average vertical displacement was around 1 m on, with strike slip ruptures averaging 2.3 m on.Baljinnyam Bayasgalan Borisov Cisternas 1993 45 The rupture lasted for a total of 65 seconds.Schlupp Cisternas 2007 1115 Bulnay earthquake The Bulnay earthquake hit remote northwestern Mongolia near Asgat Sum, Zavkhan Province at 10:46 local time on July 23, 1905. The w 8.3 earthquake ruptured along multiple faults in the Bolnai fault system for a total rupture length of 455 km on.Schlupp Cisternas 2007 1128, 1129 Rupture was unusually deep, with a maximum depth of 70 km on.Schlupp Cisternas 2007 1124 The earthquake nucleated at the junction of the Bolnai and Teregtiin faults, and ruptured along both.Rizza Ritz Prentice Vassallo 2015 74Choi Klinger Ferry Ritz 2018 1937 Bolnai fault rupture On the Bolnai fault, the earthquake ruptured bilaterally. It ruptured west for 100 km on and east for 275 km on.Rizza Ritz Prentice Vassallo 2015 74 Average displacement was 8-11 m on along the eastern segment of the fault, and 5 m on to the west. The total average displacement was 8.9 m onRizza Ritz Prentice Vassallo 2015 72Baljinnyam Bayasgalan Borisov Cisternas 1993 48 While the westward rupture had less on fault displacement, secondary features displayed enough slip to make up the difference compared to the eastern rupture, leading to an overall consistent displacement along the rupture.Choi Klinger Ferry Ritz 2018 1950 Teregtiin and Düngen fault ruptures Rupture also propagated initially along the Teregtiin fault, where it traveled southeast. The earthquake ruptured 80 km on of the fault.Rizza Ritz Prentice Vassallo 2015 74Schlupp Cisternas 2007 1129 Displacement measured between 2.2-3.0 m on along the fault.Choi Klinger Ferry Ritz 2018 1942 Rupture on the Düngen fault started 24 seconds after rupture initiated.Schlupp Cisternas 2007 1129 Rupture measured 20-30 km on.Rizza Ritz Prentice Vassallo 2015 74Schlupp Cisternas 2007 1123 Displacement is estimated to be 1-2 m on.Baljinnyam Bayasgalan Borisov Cisternas 1993 51 Multiple other faults ruptured, however their ruptures measured shorter than 10 km on.Baljinnyam Bayasgalan Borisov Cisternas 1993 45 Overall rupture duration was 115 seconds.Schlupp Cisternas 2007 1115 Surficial effects Tsetserleg Surface rupture was apparent for 130 km on. The Tsetserleg rupture produced tension gashes and mole tracks that correspond to sinistral faulting,Baljinnyam Bayasgalan Borisov Cisternas 1993 44 a complex network of fissures formed that trended east-northeast. Some of these fissures formed in parallel and created horsts and grabens.Ilyin 1978 109 Bulnay The Bulnay earthquake produced many surficial geologic effects. Surface rupture was visible for 350 km on along the Bolnai fault.Ilyin 1978 107 Mole tracks exceeding 1-2 m on were common, and tension cracks approached and even exceeded 100 m on in certain areas of the rupture.Baljinnyam Bayasgalan Borisov Cisternas 1993 45–46 Short fissures were confined to areas adjacent to the rupture.Ilyin 1978 107 Tension cracks had a north–south trend.Baljinnyam Bayasgalan Borisov Cisternas 1993 49 Damage Both earthquakes were felt over millions of square kilometers, however there are few records of the immediate effects of the earthquake due to the remoteness of Mongolia in 1905. However, rockslides were reported in the nearby mountains, and supposedly "two lakes, each of eight acres in size, disappeared". Tsetserleg was severely damaged.Okal 1977 327Gunn 2008 Scientific interest This earthquake sequence was scientifically significant for two reasons: the fact that the earthquakes likely triggered each other (and then the 1931 Fuyun and 1957 Mongolia earthquakes), and the sheer sizes of the earthquakes. The earthquake sequence was the "largest continental strike-slip earthquake sequence ever documented."Choi Klinger Ferry Ritz 2018 1926 23 research papers have been published on these earthquakes. Triggering In Mongolia, slip rates are low enough that the probabilities of multiple large (w 8+) earthquakes happening in the time span of half a century in an area where faults slip slowly is very unlikely. Studies, therefore, have investigated if there is a causal link between the ruptures. The original hypotheses was that the cause is postseismic stress relaxation, which is the process of the lithosphere realigning itself after an earthquake. Since the Coulomb stress transfer from the earthquakes wouldn't be enough to trigger failure on the relatively distant faults (~400 km on) and this effect can impact faults at much further distances, this explanation is preferred. This mechanism is similar to the earthquakes triggered by the 1992 Landers earthquake. In Mongolia there are dozens of active faults. This triggering mechanism can be applied to any group of these faults. Another study builds upon the original hypotheses, but posits that Coulomb stress transfer and viscoleastic stress transfer may better help explain the earthquakes.Chéry Carretier Ritz 2001 280–281, 283Pollitz Vergnolle Calais 2003 16-1Pollitz Vergnolle Calais 2003 16-7Pollitz Vergnolle Calais 2003 16-9Pollitz Vergnolle Calais 2003 16-10 Related events While the Tsetserleg earthquake likely triggered the Bulnay earthquake, The triggering mechanism also applies to the 1931 Fuyun earthquake and the 1957 Mongolia earthquake. Both earthquakes occurred within western Mongolia, and were likely also triggered by postseismic or viscoelastic stress relaxation, with the Bulnay earthquake triggering the 1931 Fuyun earthquake, which itself also helped trigger the 1957 Mongolia event.Chéry Carretier Ritz 2001 281Pollitz Vergnolle Calais 2003 16-10, 16-11 Size of earthquakes The earthquake sequence was the "largest continental strike-slip earthquake sequence ever documented."Choi Klinger Ferry Ritz 2018 1926 The Bulnay shock was also "one of the world's largest recorded intracontinental earthquakes."Rizza Ritz Prentice Vassallo 2015 72 Earthquakes of this size in this area have recurrence intervals on the order of thousands of years, which makes these two earthquakes occurring in such close temporal proximity a scientific curiosity.Schlupp Cisternas 2007 1115Rizza Ritz Prentice Vassallo 2015 72 See also List of earthquakes in 1905 1931 Fuyun earthquake 1957 Mongolia earthquake Notes References Fault Sources in OpenQuake https://hazard.openquake.org/gem/methods/faults/ Global Earthquake Model GEM Global Mosaic of Hazard Models 7 August 2025 OB 16957865 OB 16957859 https://earthquake.usgs.gov/earthquakes/eventpage/iscgem16957859/executive M 8.0 - The 1905 Tsetserleg, Mongolia Earthquake United States Geological Survey 2025-08-01 https://earthquake.usgs.gov/earthquakes/eventpage/iscgem16957865/executive M 8.3 - The 1905 Bulnay (Bolnai), Mongolia Earthquake United States Geological Survey 2025-08-01 Sources Baljinnyam I. Bayasgalan A. Borisov B. A. Cisternas Armando Dem'yanovich M. G. Ganbaatar L. Kochetkov V. M. Kurushin R. A. Molnar Peter Philip Hervé Vashchilov Y. Y. Ruptures of Major Earthquakes and Active Deformation in Mongolia and Its Surroundings January 1, 1993 10.1130/MEM181-p1 https://pubs.geoscienceworld.org/gsa/books/book/188/chapter-abstract/3793589/Ruptures-of-Major-Earthquakes-and-Active 4 August 2025 Chéry Jean Carretier Sébastian Ritz Jean-François Postseismic stress transfer explains time clustering of large earthquakes in Mongolia Earth and Planetary Science Letters 30 December 2001 194 1–2 277–286 10.1016/S0012-821X(01)00552-0 2001E&PSL.194..277C https://www.sciencedirect.com/science/article/abs/pii/S0012821X01005520 6 August 2025 subscription Choi Jin-Hyuck Klinger Yann Ferry Matthieu Ritz Jean-François Kurtz Robin Rizza Magali Bollinger Laurent Davaasambuu Battogtokh Tsend-Ayush Nyambayar Demberel Sodnomsambuu Geologic Inheritance and Earthquake Rupture Processes: The 1905 M ≥ 8 Tsetserleg-Bulnay Strike-Slip Earthquake Sequence, Mongolia Journal of Geophysical Research: Solid Earth 25 January 2018 123 2 1925–1953 10.1002/2017JB013962 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JB013962 1 August 2025 Gunn Angus McLeod Encyclopedia of Disasters: Environmental Catastrophes and Human Tragedies https://books.google.com/books?id=4YzF-DT__aIC&pg=PA215 215–216 2008 978-0-313-34002-4 Greenwood Press Westport, Connecticut Earth and Planetary Science Letters 41 1 September 1978 107–109 Comment on "The July 9 and 23, 1905, Mongolian earthquakes, a surface-wave investigation" by Emile Okal A.V. Ilyin 10.1016/0012-821X(78)90047-X 1978E&PSL..41..107I The July 9 and 23, 1905, Mongolian earthquakes: A surface wave investigation Emile A. Okal Earth and Planetary Science Letters 34 2 March 1977 326–331 10.1016/0012-821X(77)90018-8 1977E&PSL..34..326O Okal Emile A. Use of the mantle magnitudeM m for the reassessment of the moment of historical earthquakes Pure and Applied Geophysics March 1992 139 1 17–57 10.1007/BF00876825 1992PApGe.139...17O 129383199 https://link.springer.com/article/10.1007/BF00876825 5 August 2025 subscription Fred Pollitz Mathilde Vergnolle Eric Calais Fault interaction and stress triggering of twentieth century earthquakes in Mongolia https://profile.usgs.gov/myscience/upload_folder/ci2011May3115100837182Pollitz_JGR2003.pdf Journal of Geophysical Research 108 B10 2503 10.1029/2002JB002375 25 October 2003 2003JGRB..108.2503P 12 March 2015 https://web.archive.org/web/20161221230131/https://profile.usgs.gov/myscience/upload_folder/ci2011May3115100837182Pollitz_JGR2003.pdf 21 December 2016 dead Richter Charles F. Elementary Seismology 1958 W. H. Freeman 978-0716702115 58-5970 Rizza M. Ritz J. F. Prentice C. Vassallo R. Braucher R. Larroque C. Arzhannikova A. Arzhannikov S. Mahan S. Massault M. Michelot J. L. Todbileg M. Earthquake Geology of the Bulnay Fault (Mongolia) Bulletin of the Seismological Society of America January 13, 2015 105 1 72–93 10.1785/0120140119 https://pubs.geoscienceworld.org/ssa/bssa/article/105/1/72/323656/Earthquake-Geology-of-the-Bulnay-Fault-Mongolia 1 August 2025 Schlupp Antoine Cisternas Armando June 2007 Source history of the 1905 great Mongolian earthquakes (Tsetserleg, Bolnay) Geophysical Journal International 169 1115–1131 3 10.1111/j.1365-246X.2007.03323.x 2007GeoJI.169.1115S free External links 16957859 Category:1905 earthquakes Category:July 1905 in Asia Category:1905 disasters in Asia Category:1905 disasters in China Category:1905 disasters in Mongolia Category:1905 in China Category:1905 in Mongolia Category:Earthquakes in Mongolia Category:Strike-slip earthquakes