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== Geomorphology ==
== Geomorphology ==
The Sagaing Fault begins offshore in the Andaman Sea before passing through the [[Geology of Myanmar#Myanmar Central Belt|central Myanmar basin]]. The fault has a relatively low topographical relief for most of its length compared to the [[Shan Scarp Fault]] to the [[Shan Hills|west]].<ref>{{Cite journal|last=SOE THURA TUN, WATKINSON|title=The Sagaing Fault|url=https://pure.royalholloway.ac.uk/portal/files/29857365/Soe_Thura_Tun_and_Watkinson_accepted.pdf|journal=Myanmar: Geology, Resources and Tectonics|volume=Geological Society, London, Memoir}}</ref>
The Sagaing Fault begins offshore in the Andaman Sea before passing through the [[Geology of Myanmar#Myanmar Central Belt|central Myanmar basin]]. The fault has a relatively low topographical relief for most of its length compared to the [[Shan Scarp Fault]] to the [[Shan Hills|west]].<ref name="Tun & Watkinson" />


== Slip rate and displacement ==
== Slip rate and displacement ==
The total slip rate across the Indian–Sunda Plate boundary is about 35 mm/yr, of which 18&nbsp;mm/yr is accommodated by the Sagaing Fault, according to [[Global Positioning System|GPS]] data.<ref name="Tsutsumi_&_Sato_2009">{{Cite journal |last1=Tsutsumi |first1=H. |last2=Sato |first2=T. |date=2009 |title=Tectonic geomorphology of the southernmost Sagaing fault and surface rupture associated with the May 1930 Pegu (Bago) earthquake, Myanmar |journal=Bulletin of the Seismological Society of America |volume=99 |issue=4 |pages=2155–2168 |doi=10.1785/0120080113}}</ref> The measured maximum displacement along the fault is about 100 km, although several authors have proposed between 360 km to 400 km.<ref name=":1">{{Cite journal|last=Yu|first=Wang|title=Active tectonics and earthquake potential of the Myanmar region|url=https://authors.library.caltech.edu/47518/1/jgrb50602.pdf|journal=Journal of Geophysical Research: Solid Earth|year=2014|volume=119|issue=4|page=3767|doi=10.1002/2013JB010762|bibcode=2014JGRB..119.3767W|via=Caltech|doi-access=free}}</ref><ref>{{Cite journal|last=Yu Wang, Kerry Sieh, Thura Aung, Soe Min, Saw Ngwe Khaing|title=Earthquakes and slip rate of the southern Sagaing fault: insights from an offset ancient fort wall, lower Burma (Myanmar)|journal=Geophysical Journal International|year=2011|volume=185|issue=1|page=49|doi=10.1111/j.1365-246X.2010.04918.x|bibcode=2011GeoJI.185...49W|doi-access=free}}</ref>
The total slip rate across the Indian–Sunda Plate boundary is about 35 mm/yr, of which 18&nbsp;mm/yr is accommodated by the Sagaing Fault, according to [[Global Positioning System|GPS]] data.<ref name="Tsutsumi_&_Sato_2009">{{Cite journal |last1=Tsutsumi |first1=H. |last2=Sato |first2=T. |date=2009 |title=Tectonic geomorphology of the southernmost Sagaing fault and surface rupture associated with the May 1930 Pegu (Bago) earthquake, Myanmar |journal=Bulletin of the Seismological Society of America |volume=99 |issue=4 |pages=2155–2168 |doi=10.1785/0120080113}}</ref> The measured maximum displacement along the fault is about 100 km, although several authors have proposed between 360 km to 400 km.<ref name=":1">{{Cite journal|last=Yu|first=Wang|title=Active tectonics and earthquake potential of the Myanmar region|url=https://authors.library.caltech.edu/47518/1/jgrb50602.pdf|journal=Journal of Geophysical Research: Solid Earth|year=2014|volume=119|issue=4|page=3767|doi=10.1002/2013JB010762|bibcode=2014JGRB..119.3767W|via=Caltech|doi-access=free}}</ref><ref>{{Cite journal|last=Yu Wang, Kerry Sieh, Thura Aung, Soe Min, Saw Ngwe Khaing|title=Earthquakes and slip rate of the southern Sagaing fault: insights from an offset ancient fort wall, lower Burma (Myanmar)|journal=Geophysical Journal International|year=2011|volume=185|issue=1|page=49|doi=10.1111/j.1365-246X.2010.04918.x|bibcode=2011GeoJI.185...49W|doi-access=free}}</ref>


==Seismicity==
==Associated seismicity==
{{See also|List of earthquakes in Myanmar}}
{{See also|List of earthquakes in Myanmar}}
[[File:Mingun stupa 1839 earthquake damage.jpg|200px|thumb|right|A large fracture on the [[Mingun Pahtodawgyi]] caused by the [[1839 Ava earthquake]].]]
In the early 20th century, more than half the length of the Sagaing Fault was involved in significant earthquakes.
Damaging earthquakes have been associated with the fault for centuries. The great [[1839 Ava earthquake]] killed hundreds and damaged many cities, including the then imperial capital [[Inwa]].<ref name="NGDC" /> That earthquake is thought to have a moment magnitude of 8.0 or greater. The large magnitude would imply a rupture lenght of at least 300 km along the fault.
=== August 8 1929 ===
⚫
The first earthquake that would be followed-up by subsequent larger events struck southwest of Nay Pyi Daw, and east of [[Thayet|Thayetmyo]] in the Pegu Range.<ref>{{Cite web|title=M 6.6 - Myanmar|url=https://earthquake.usgs.gov/earthquakes/eventpage/iscgem908257/executive|website=USGS}}</ref> There is insufficient reports of damage caused by this earthquake although it was said that buildings were swaying and objects were displaced at [[Yamethin Township|Yamethin]], roughly 133.6 km north of the quake epicenter.<ref name=":2">{{Cite journal|last=Hla Hla Aung|title=Reinterpretation of historical earthquakes during 1929 to 1931, Myanmar|url=https://www.researchgate.net/publication/275354874|journal=Solid Earth Science|year=2012|volume=31|page=43|doi=10.1142/9789814405775_0005|bibcode=2012aogs...31...43A|isbn=978-981-4405-76-8|via=Researchgate|doi-access=free}}</ref> The magnitude of this earthquake was no greater than 7.0.


⚫
In the early 20th century, from 1929–1931, more than half the length of the Sagaing Fault was involved in significant earthquakes. The first earthquake that would be followed-up by subsequent larger events struck southwest of Nay Pyi Daw, and east of [[Thayet|Thayetmyo]] in the Pegu Range in August 1929.<ref>{{Cite web|title=M 6.6 - Myanmar|url=https://earthquake.usgs.gov/earthquakes/eventpage/iscgem908257/executive|website=USGS}}</ref> There is insufficient reports of damage caused by this earthquake although it was said that buildings were swaying and objects were displaced at [[Yamethin Township|Yamethin]], roughly 133.6 km north of the quake epicenter.<ref name=":2">{{Cite journal|last=Hla Hla Aung|title=Reinterpretation of historical earthquakes during 1929 to 1931, Myanmar|url=https://www.researchgate.net/publication/275354874|journal=Solid Earth Science|year=2012|volume=31|page=43|doi=10.1142/9789814405775_0005|bibcode=2012aogs...31...43A|isbn=978-981-4405-76-8|via=Researchgate|doi-access=free}}</ref> The magnitude of this earthquake was no greater than 7.0.
=== July 18 1930 ===
⚫
A less-known earthquake in the [[Ayeyarwady Region|Irrawaddy Division]] killed about 50 people.<ref>{{Cite web|title=Significant Earthquake: MYANMAR (BURMA): THARRAWADDY|url=https://www.ngdc.noaa.gov/nndc/struts/results?eq_0=3416&t=101650&s=13&d=22,26,13,12&nd=display|website=NOAA}}</ref> There is no magnitude assigned to this event, very few published journals mentioned this event.


⚫
On the night of May 5, [[1930 Bago earthquake|a large shock]] registering {{M|w}} 7.5 struck north of the city of [[Bago, Myanmar|Pegu]] resulting in widespread deaths and destruction.<ref>{{Cite web|title=M 7.5 - Myanmar|url=https://earthquake.usgs.gov/earthquakes/eventpage/iscgem907352/executive|website=USGS}}</ref> There were no foreshocks that preceded. The earthquake had a maximum intensity of IX to X on the [[Rossi–Forel scale|Rossi-Forel scale]].<ref name=":1" /> The city of Pegu, [[Yangon|Rangoon]] and several other towns were destroyed. In Pegu, fires erupted and severe liquefaction caused further damage. Approximately 500 people died in Pegu while 58 were killed in Rangoon, more deaths were recorded in other villages.<ref name=":2" /> It triggered a small [[tsunami]] in that inundated villages along the coast.<ref name="NGDC" /> This is the deadliest earthquake in the 1929–1931 sequence.
=== May 5 1930 ===
{{Main|1930 Pegu earthquake}}

⚫
On the night of May 5, a large shock registering {{M|w}}7.5 struck north of the city of [[Bago, Myanmar|Pegu]] resulting in widespread deaths and destruction.<ref>{{Cite web|title=M 7.5 - Myanmar|url=https://earthquake.usgs.gov/earthquakes/eventpage/iscgem907352/executive|website=USGS}}</ref> There were no foreshocks that preceded. The earthquake had a maximum intensity of IX to X on the [[Rossi–Forel scale|Rossi-Forel scale]].<ref name=":1" /> The city of Pegu, [[Yangon|Rangoon]] and several other towns were destroyed. In Pegu, fires erupted and severe liquefaction caused further damage. Approximately 500 people died in Pegu while 58 were killed in Rangoon, more deaths were recorded in other villages.<ref name=":2" /> It triggered a small [[tsunami]] in that inundated villages along the coast. This is the deadliest earthquake in the 1929-1931 sequence.

=== December 4 1930 ===
{{Main|1930 Pyu earthquake}}


The night of December 3 was disturbed by two moderate foreshocks, the first lasting 5 seconds generated some panic, it was felt in [[Pyinmana]] and Rangoon and another that was described as being stronger than the first but was not felt as widespread like the first.<ref name=":3">{{Cite journal|last=J. COGGIN BROWN AND P. LEICESTER|title=THE PYU EARTHQUAKES of 3RD AND 4TH DECEMBER 1930 AND SUBSEQUENT BURMA EARTHQUAKES UP TO JANUARY 1932|url=https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxpbmRpYXF1YWtlMnxneDo1MjA4MWMzY2NhNjgyYTRi|journal=Memoirs of the Geological Survey of India |volume=LXII}}</ref><ref>{{Cite web|title=Event 907776 Myanmar|url=http://isc-mirror.iris.washington.edu/cgi-bin/web-db-v4?event_id=907776&out_format=IMS1.0&request=COMPREHENSIVE|website=International Seismological Centre}}</ref><ref>{{Cite web|title=Event 907775 Near south coast of Myanmar|url=http://isc-mirror.iris.washington.edu/cgi-bin/web-db-v4?event_id=907775&out_format=IMS1.0&request=COMPREHENSIVE|website=International Seismological Centre}}</ref>
The night of December 3 was disturbed by two moderate foreshocks, the first lasting 5 seconds generated some panic, it was felt in [[Pyinmana]] and Rangoon and another that was described as being stronger than the first but was not felt as widespread like the first.<ref name=":3">{{Cite journal|last=J. COGGIN BROWN AND P. LEICESTER|title=THE PYU EARTHQUAKES of 3RD AND 4TH DECEMBER 1930 AND SUBSEQUENT BURMA EARTHQUAKES UP TO JANUARY 1932|url=https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxpbmRpYXF1YWtlMnxneDo1MjA4MWMzY2NhNjgyYTRi|journal=Memoirs of the Geological Survey of India |volume=LXII}}</ref><ref>{{Cite web|title=Event 907776 Myanmar|url=http://isc-mirror.iris.washington.edu/cgi-bin/web-db-v4?event_id=907776&out_format=IMS1.0&request=COMPREHENSIVE|website=International Seismological Centre}}</ref><ref>{{Cite web|title=Event 907775 Near south coast of Myanmar|url=http://isc-mirror.iris.washington.edu/cgi-bin/web-db-v4?event_id=907775&out_format=IMS1.0&request=COMPREHENSIVE|website=International Seismological Centre}}</ref>


The early morning of December 4 in [[Pyu]], [[Taungoo District]] was suddenly disrupted by violent shaking from an {{M|w}}7.3 earthquake.<ref>{{Cite web|title=M 7.4 - Myanmar|url=https://earthquake.usgs.gov/earthquakes/eventpage/iscgem907777/executive|website=USGS}}</ref> The December 4 event occurred further north of the epicenter of the May earthquake, about 6.4 to 9.7 km west southwest of Pyu. Damage was severe, a railroad was shifted off and twisted while many buildings in the city collapsed. About 30 people were killed. Intensity reached X on the Rossi-Forel scale.<ref name=":3" /> This event is not an aftershock of the May quake because it ruptured a different segment of the Sagaing Fault.<ref name=":1" />
The early morning of December 4 in [[Pyu]], [[Taungoo District]] was suddenly disrupted by violent shaking from an {{M|w}} [[1930 Pyu earthquake|7.3 earthquake]].<ref>{{Cite web|title=M 7.4 - Myanmar|url=https://earthquake.usgs.gov/earthquakes/eventpage/iscgem907777/executive|website=USGS}}</ref> The December 4 event occurred further north of the epicenter of the May earthquake, about 6.4 to 9.7 km west southwest of Pyu. Damage was severe, a railroad was shifted off and twisted while many buildings in the city collapsed. About 30 people were killed. The maximum intensity was assigned X on the [[Rossi–Forel scale]].<ref name=":3" /> This event is not an aftershock of the May quake because it ruptured a different segment of the Sagaing Fault.<ref name=":1" />


⚫
Although the May and December 1930 earthquakes occurred during this active period, they were separate events, unrelated to the activity in the northern part. The December 1930 earthquake, however, was triggered due to stress transfer from the previous event in May.<ref name="Coulomb stress transfer and accumulation on the Sagaing Fault, Myanmar, over the past 110 years and its implications for seismic hazard" />
=== January 31 1931 ===
{{Main|1931 Kamaing earthquake}}


⚫
A lesser-known earthquake on July 18, 1930 in the [[Ayeyarwady Region]] killed about 50 people.<ref>{{Cite web|title=Significant Earthquake: MYANMAR (BURMA): THARRAWADDY|url=https://www.ngdc.noaa.gov/nndc/struts/results?eq_0=3416&t=101650&s=13&d=22,26,13,12&nd=display|website=NOAA}}</ref> According to the [[National Centers for Environmental Information]] database, there is no magnitude assigned to this event.<ref name="NGDC" /> The book ''Southeast Asia Association of Seismology'' is the only published work mentioning this event.<ref name="Nutalaya">{{cite book |author1=Nutalaya |author2=P.S. Sodsri |author3=E.P. Arnold |title=SEASEE Series on Seismology |date=1985 |publisher=[[U.S. Geological Survey]] |edition=|series=Series on Seismology |chapter=|volume=II-Thailand}}</ref>
⚫
The largest earthquake in the sequence, an {{M|w}}7.6 quake struck next to [[Indawgyi Lake]] resulting in large [[Landslide|landslides]] and [[Liquefaction|ground failures]].<ref name=":2" /><ref>{{Cite web|title=M 7.6 - Myanmar|url=https://earthquake.usgs.gov/earthquakes/eventpage/iscgem906595/executive|website=USGS}}</ref> There were no casualties in this earthquakes.


⚫
The [[1931 Myitkyina earthquake|largest earthquake]] in the sequence, an {{M|w}} 7.6 quake struck next to [[Indawgyi Lake]] resulting in large [[Landslide|landslides]] and [[Liquefaction|ground failures]].<ref name=":2" /><ref>{{Cite web|title=M 7.6 - Myanmar|url=https://earthquake.usgs.gov/earthquakes/eventpage/iscgem906595/executive|website=USGS}}</ref> There were no casualties in this earthquakes.
=== August 10 - 19 1931 ===
⚫
A violent earthquake of unknown magnitude 146.5 km north of Pyu. It was felt in [[Mandalay]] and [[Thanatpin]].<ref name=":2" /> Six brick buildings sustained damage. On August 19, another tremor caused cracks to appear in buildings in Mandalay and lightly affected [[Kalaw]].<ref name=":3" />


⚫
Another violent earthquake of unknown magnitude occurred 146.5 km north of Pyu. It was felt in [[Mandalay]] and [[Thanatpin]].<ref name=":2" /> Six brick buildings sustained damage. On August 19, another tremor caused cracks to appear in buildings in Mandalay and lightly affected [[Kalaw]].<ref name=":3" /> The city was rocked another time, resulted in the collapse of the Shwe Sandaw Pagoda in Taungoo.<ref name=":2" />
=== September 23 1931 ===
Another earthquake in Pyu resulted in the collapse of the Shwe Sandaw Pagoda in Taungoo.<ref name=":2" />


=== January 5-13 1932 ===
Several short tremors were felt that woke people up in Taungoo, [[Pyuntaza]] and [[Nanyun Township|Nangyun]].<ref name=":3" />
Several short tremors were felt that woke people up in Taungoo, [[Pyuntaza]] and [[Nanyun Township|Nangyun]].<ref name=":3" />


⚫
[[1946 Sagaing earthquakes|Two powerful earthquakes]] north of Mandalay measuring 8.0 and 7.7 on the moment magnitude scale occurred on September 12, 1946.<ref name="ISC-GEM" /> The [[doublet earthquake]] sequence would remain as one of the largest in the country. Not much about this event is known due to sparse records.
=== September 09 1946===
{{Main|1946 Sagaing earthquakes}}
⚫
Two powerful earthquakes north of Mandalay measuring 8.0 and 7.8 on the moment magnitude scale would remain as one of the largest in the country. Not much about this event is known due to sparse records.


=== July 16 1956 ===
{{Main|1956 Sagaing earthquake}}
This magnitude 7.1 earthquake near the city of Mandalay resulted in the deaths of at least 38 people.

==== Cause ====
Looking back at the historical records of earthquakes, the years 1906 and 1908 saw two major events in the northernmost end of the Sagaing Fault.<ref name="Coulomb stress transfer and accumulation on the Sagaing Fault, Myanmar, over the past 110 years and its implications for seismic hazard">{{cite journal |last1=Xiong, X., B. Shan, Y. M. Zhou, S. J. Wei, Y. D. Li, R. J. Wang, and Y. Zheng |title=Coulomb stress transfer and accumulation on the Sagaing Fault, Myanmar, over the past 110 years and its implications for seismic hazard |journal=Geophysical Research Letters |date=2017 |volume=44 |issue=10 |page=4781–4789 |doi=10.1002/2017GL072770 |url=https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017GL072770}}</ref> The 1906 Putao earthquake on August 31 had an estimated moment magnitude of 7.0, and the 1908 earthquake measured {{M|w}} 7.5.<ref name="Event 914281 Myanmar-India border region">{{cite web |title=Event 914281 Myanmar-India border region |url=http://isc-mirror.iris.washington.edu/cgi-bin/web-db-v4?event_id=914281&out_format=IMS1.0&request=COMPREHENSIVE |website=ISC: On-Line Bulletin |publisher=International Seismological Center |access-date=3 March 2021}}</ref><ref name="Event 16958007 Myanmar (1908)">{{cite web |title=Event 16958007 Myanmar |url=http://isc-mirror.iris.washington.edu/cgi-bin/web-db-v4?event_id=16958007&out_format=IMS1.0&request=COMPREHENSIVE |website=ISC: On-Line Bulletin |publisher=International Seismological Centre |access-date=3 March 2021}}</ref>
Looking back at the historical records of earthquakes, the years 1906 and 1908 saw two major events in the northernmost end of the Sagaing Fault.<ref name="Coulomb stress transfer and accumulation on the Sagaing Fault, Myanmar, over the past 110 years and its implications for seismic hazard">{{cite journal |last1=Xiong, X., B. Shan, Y. M. Zhou, S. J. Wei, Y. D. Li, R. J. Wang, and Y. Zheng |title=Coulomb stress transfer and accumulation on the Sagaing Fault, Myanmar, over the past 110 years and its implications for seismic hazard |journal=Geophysical Research Letters |date=2017 |volume=44 |issue=10 |page=4781–4789 |doi=10.1002/2017GL072770 |url=https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017GL072770}}</ref> The 1906 Putao earthquake on August 31 had an estimated moment magnitude of 7.0, and the 1908 earthquake measured {{M|w}} 7.5.<ref name="Event 914281 Myanmar-India border region">{{cite web |title=Event 914281 Myanmar-India border region |url=http://isc-mirror.iris.washington.edu/cgi-bin/web-db-v4?event_id=914281&out_format=IMS1.0&request=COMPREHENSIVE |website=ISC: On-Line Bulletin |publisher=International Seismological Center |access-date=3 March 2021}}</ref><ref name="Event 16958007 Myanmar (1908)">{{cite web |title=Event 16958007 Myanmar |url=http://isc-mirror.iris.washington.edu/cgi-bin/web-db-v4?event_id=16958007&out_format=IMS1.0&request=COMPREHENSIVE |website=ISC: On-Line Bulletin |publisher=International Seismological Centre |access-date=3 March 2021}}</ref>

The 1908 earthquake resulted in the accumulation of stress towards the south, where the future 1931 quake would take place. Similarly, the 1946 earthquake rupture segments were directly south of the 1931 rupture. The first mainshock in the 1946 doublet sequence then triggered the second mainshock due to the sudden increase in stress levels on the fault.
The 1908 earthquake resulted in the accumulation of stress towards the south, where the future 1931 quake would take place. Similarly, the 1946 earthquake rupture segments were directly south of the 1931 rupture. The first mainshock in the 1946 doublet sequence then triggered the second mainshock due to the sudden increase in stress levels on the fault.
⚫
Ten years later, an {{M|w}} [[1956 Sagaing earthquake|7.1 earthquake near Mandalay]] killed at least 40 people. That earthquake broke a segment south of the 1946 rupture. In 1991, a small seismic gap between the two 1946 ruptures generated an {{M|w}} 7.0 earthquake, partially re-rupturing a small section of the 1946 quakes, killing two.<ref name="M 7.0 - Myanmar">{{cite web |title=M 7.0 - Myanmar |url=https://earthquake.usgs.gov/earthquakes/eventpage/usp0004k8g/executive |website=USGS-ANSS |publisher=USGS |access-date=3 March 2021}}</ref>
⚫
Although the May and December 1930 earthquakes occurred during this active period, they were separate events, unrelated to the activity in the northern part. The December 1930 earthquake, however, was triggered due to stress transfer from the previous event in May.<ref name="Coulomb stress transfer and accumulation on the Sagaing Fault, Myanmar, over the past 110 years and its implications for seismic hazard" />


⚫
Ten years later, an {{M|w}} [[1956 Sagaing earthquake|7.1 earthquake near Mandalay]] killed at least 40 people.<ref name="NGDC" /> That earthquake broke a segment south of the 1946 rupture. In 1991, a small seismic gap between the two 1946 ruptures generated an {{M|w}} 7.0 earthquake, partially re-rupturing a small section of the 1946 quakes, killing two.<ref name="M 7.0 - Myanmar">{{cite web |title=M 7.0 - Myanmar |url=https://earthquake.usgs.gov/earthquakes/eventpage/usp0004k8g/executive |website=USGS-ANSS |publisher=USGS |access-date=3 March 2021}}</ref>
===Other earthquakes===

* [[1839 Ava earthquake]]: Powerful quake that destroyed the city of [[Inwa]].<ref>{{Cite web|last=Htoo|first=Thant|date=2019-08-07|title=Govt unveils quake preparedness plan|url=https://www.mmtimes.com/news/govt-unveils-quake-preparedness-plan.html|access-date=2020-08-30|website=The Myanmar Times}}</ref>
The [[2012 Shwebo earthquake]] was the most recent major event on the Sagaing Fault. It had a moment magnitude of 6.8 and ruptured the fault north of Mandalay. A detailed and thorough evaluation of the event suggest the rupture was estimated at 45-km-long. The centroid moment tensor solution suggested the earthquake ruptured a north-south trending and sub-vertical fault that steeply dipped to the east.<ref name="Tun & Watkinson" />
* [[2012 Shwebo earthquake]]: Magnitude 6.8 quake killed 26 people and left 12 missing.


==See also==
==See also==
Line 67: Line 47:


==References==
==References==
{{reflist|2}}
{{reflist|refs=
<ref name="ISC-GEM">{{citation|title=ISC-GEM Global Instrumental Earthquake Catalogue (1900–2012)|url=http://www.isc.ac.uk/iscgem/index.php|author=ISC|year=2016|publisher=[[International Seismological Centre]]|series=Version 3.0}}</ref>

<ref name=NGDC>{{citation|title=Significant Earthquake Database|url=https://www.ngdc.noaa.gov/nndc/struts/form?t=101650&s=1&d=1|author=National Geophysical Data Center / World Data Service (NGDC/WDS)|publisher=[[National Geophysical Data Center]], [[National Oceanic and Atmospheric Administration|NOAA]]|doi=10.7289/V5TD9V7K|year=1972|type = Data Set}}</ref>
<ref name="Tun & Watkinson">{{cite journal |author1=Soe Thura Tun |author2=Ian M. Watkinson |title=Myanmar: Geology, Resources and Tectonics |journal=Geological Society, London, Memoirs |date=2017 |volume=48 |pages=413-441 |doi=10.1144/M48.19}}</ref>}}
==External links==
==External links==
* [https://web.archive.org/web/20121223073524/http://www.earthobservatory.sg/media/news-and-features/295-myanmar-earthquake-of-march-24th-magnitude-68.html Earth Observatory of Singapore: Myanmar earthquake of March 24th - Magnitude 6.8 (Regional Tectonics Explained)]
* [https://web.archive.org/web/20121223073524/http://www.earthobservatory.sg/media/news-and-features/295-myanmar-earthquake-of-march-24th-magnitude-68.html Earth Observatory of Singapore: Myanmar earthquake of March 24th - Magnitude 6.8 (Regional Tectonics Explained)]

Revision as of 07:51, 12 January 2022

Sagaing Fault
A pressure ridge formed along the fault, obscured by vegetation.
Coordinates21°55'06.8"N 95°59'01.6"E
CountryMyanmar
CitiesYangon, Nay Pyi Taw, Meiktila, Mandalay, Myitkyina
Characteristics
SegmentsSouthern section: Bago, Pyu, Nay Pyi Taw, Meiktila, Sagaing. Northern section: Tawma, Ban Mauk, Indaw, Mawlu, Shaduzup, Kamaing, Mogang
Length1,400 km
Displacement18-20 mm/yr (0.71-0.79 in/yr)
Tectonics
StatusActive
TypeTransform fault
MovementDextral
Age15-22 MYA

The Sagaing Fault is a major fault in Burma, a mainly continental right-lateral transform fault between the Indian Plate and Sunda Plate. It links the divergent boundary in the Andaman Sea with the zone of active continental collision along the Himalayan front. It passes through populated cities of Mandalay, Yamethin, Pyinmana, the capital Naypyidaw, Toungoo and Pegu before dropping off into the Gulf of Martaban, running for a total length of over 1200 kilometers.[1][2]

Geomorphology

The Sagaing Fault begins offshore in the Andaman Sea before passing through the central Myanmar basin. The fault has a relatively low topographical relief for most of its length compared to the Shan Scarp Fault to the west.[3]

Slip rate and displacement

The total slip rate across the Indian–Sunda Plate boundary is about 35 mm/yr, of which 18 mm/yr is accommodated by the Sagaing Fault, according to GPS data.[4] The measured maximum displacement along the fault is about 100 km, although several authors have proposed between 360 km to 400 km.[5][6]

Seismicity

See also: List of earthquakes in Myanmar
A large fracture on the Mingun Pahtodawgyi caused by the 1839 Ava earthquake.

Damaging earthquakes have been associated with the fault for centuries. The great 1839 Ava earthquake killed hundreds and damaged many cities, including the then imperial capital Inwa.[7] That earthquake is thought to have a moment magnitude of 8.0 or greater. The large magnitude would imply a rupture lenght of at least 300 km along the fault.

In the early 20th century, from 1929–1931, more than half the length of the Sagaing Fault was involved in significant earthquakes. The first earthquake that would be followed-up by subsequent larger events struck southwest of Nay Pyi Daw, and east of Thayetmyo in the Pegu Range in August 1929.[8] There is insufficient reports of damage caused by this earthquake although it was said that buildings were swaying and objects were displaced at Yamethin, roughly 133.6 km north of the quake epicenter.[9] The magnitude of this earthquake was no greater than 7.0.

On the night of May 5, a large shock registering Mw  7.5 struck north of the city of Pegu resulting in widespread deaths and destruction.[10] There were no foreshocks that preceded. The earthquake had a maximum intensity of IX to X on the Rossi-Forel scale.[5] The city of Pegu, Rangoon and several other towns were destroyed. In Pegu, fires erupted and severe liquefaction caused further damage. Approximately 500 people died in Pegu while 58 were killed in Rangoon, more deaths were recorded in other villages.[9] It triggered a small tsunami in that inundated villages along the coast.[7] This is the deadliest earthquake in the 1929–1931 sequence.

The night of December 3 was disturbed by two moderate foreshocks, the first lasting 5 seconds generated some panic, it was felt in Pyinmana and Rangoon and another that was described as being stronger than the first but was not felt as widespread like the first.[11][12][13]

The early morning of December 4 in Pyu, Taungoo District was suddenly disrupted by violent shaking from an Mw  7.3 earthquake.[14] The December 4 event occurred further north of the epicenter of the May earthquake, about 6.4 to 9.7 km west southwest of Pyu. Damage was severe, a railroad was shifted off and twisted while many buildings in the city collapsed. About 30 people were killed. The maximum intensity was assigned X on the Rossi–Forel scale.[11] This event is not an aftershock of the May quake because it ruptured a different segment of the Sagaing Fault.[5]

Although the May and December 1930 earthquakes occurred during this active period, they were separate events, unrelated to the activity in the northern part. The December 1930 earthquake, however, was triggered due to stress transfer from the previous event in May.[15]

A lesser-known earthquake on July 18, 1930 in the Ayeyarwady Region killed about 50 people.[16] According to the National Centers for Environmental Information database, there is no magnitude assigned to this event.[7] The book Southeast Asia Association of Seismology is the only published work mentioning this event.[17]

The largest earthquake in the sequence, an Mw  7.6 quake struck next to Indawgyi Lake resulting in large landslides and ground failures.[9][18] There were no casualties in this earthquakes.

Another violent earthquake of unknown magnitude occurred 146.5 km north of Pyu. It was felt in Mandalay and Thanatpin.[9] Six brick buildings sustained damage. On August 19, another tremor caused cracks to appear in buildings in Mandalay and lightly affected Kalaw.[11] The city was rocked another time, resulted in the collapse of the Shwe Sandaw Pagoda in Taungoo.[9]

Several short tremors were felt that woke people up in Taungoo, Pyuntaza and Nangyun.[11]

Two powerful earthquakes north of Mandalay measuring 8.0 and 7.7 on the moment magnitude scale occurred on September 12, 1946.[19] The doublet earthquake sequence would remain as one of the largest in the country. Not much about this event is known due to sparse records.

Looking back at the historical records of earthquakes, the years 1906 and 1908 saw two major events in the northernmost end of the Sagaing Fault.[15] The 1906 Putao earthquake on August 31 had an estimated moment magnitude of 7.0, and the 1908 earthquake measured Mw  7.5.[20][21]

The 1908 earthquake resulted in the accumulation of stress towards the south, where the future 1931 quake would take place. Similarly, the 1946 earthquake rupture segments were directly south of the 1931 rupture. The first mainshock in the 1946 doublet sequence then triggered the second mainshock due to the sudden increase in stress levels on the fault.

Ten years later, an Mw  7.1 earthquake near Mandalay killed at least 40 people.[7] That earthquake broke a segment south of the 1946 rupture. In 1991, a small seismic gap between the two 1946 ruptures generated an Mw  7.0 earthquake, partially re-rupturing a small section of the 1946 quakes, killing two.[22]

The 2012 Shwebo earthquake was the most recent major event on the Sagaing Fault. It had a moment magnitude of 6.8 and ruptured the fault north of Mandalay. A detailed and thorough evaluation of the event suggest the rupture was estimated at 45-km-long. The centroid moment tensor solution suggested the earthquake ruptured a north-south trending and sub-vertical fault that steeply dipped to the east.[3]

See also

References

  1. ^ Win, Nilar (August 25–31, 2008). "Sagaing Fault surveyed to prepare for future quakes". The Myanmar Times. Archived from the original on 2012-06-07. Retrieved 2011-04-04.
  2. ^ Wang, Yu (2011). "Earthquakes and slip rate of the southern Sagaing fault: insights from an offset ancient fort wall, lower Burma (Myanmar)" (PDF). Geophysical Journal International. 185: 49–64. doi:10.1111/j.1365-246X.2010.04918.x.
  3. ^ a b Soe Thura Tun; Ian M. Watkinson (2017). "Myanmar: Geology, Resources and Tectonics". Geological Society, London, Memoirs. 48: 413–441. doi:10.1144/M48.19.
  4. ^ Tsutsumi, H.; Sato, T. (2009). "Tectonic geomorphology of the southernmost Sagaing fault and surface rupture associated with the May 1930 Pegu (Bago) earthquake, Myanmar". Bulletin of the Seismological Society of America. 99 (4): 2155–2168. doi:10.1785/0120080113.
  5. ^ a b c Yu, Wang (2014). "Active tectonics and earthquake potential of the Myanmar region" (PDF). Journal of Geophysical Research: Solid Earth. 119 (4): 3767. Bibcode:2014JGRB..119.3767W. doi:10.1002/2013JB010762 – via Caltech.
  6. ^ Yu Wang, Kerry Sieh, Thura Aung, Soe Min, Saw Ngwe Khaing (2011). "Earthquakes and slip rate of the southern Sagaing fault: insights from an offset ancient fort wall, lower Burma (Myanmar)". Geophysical Journal International. 185 (1): 49. Bibcode:2011GeoJI.185...49W. doi:10.1111/j.1365-246X.2010.04918.x.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ^ a b c d National Geophysical Data Center / World Data Service (NGDC/WDS) (1972), Significant Earthquake Database (Data Set), National Geophysical Data Center, NOAA, doi:10.7289/V5TD9V7K
  8. ^ "M 6.6 - Myanmar". USGS.
  9. ^ a b c d e Hla Hla Aung (2012). "Reinterpretation of historical earthquakes during 1929 to 1931, Myanmar". Solid Earth Science. 31: 43. Bibcode:2012aogs...31...43A. doi:10.1142/9789814405775_0005. ISBN 978-981-4405-76-8 – via Researchgate.
  10. ^ "M 7.5 - Myanmar". USGS.
  11. ^ a b c d J. COGGIN BROWN AND P. LEICESTER. "THE PYU EARTHQUAKES of 3RD AND 4TH DECEMBER 1930 AND SUBSEQUENT BURMA EARTHQUAKES UP TO JANUARY 1932". Memoirs of the Geological Survey of India. LXII.
  12. ^ "Event 907776 Myanmar". International Seismological Centre.
  13. ^ "Event 907775 Near south coast of Myanmar". International Seismological Centre.
  14. ^ "M 7.4 - Myanmar". USGS.
  15. ^ a b Xiong, X., B. Shan, Y. M. Zhou, S. J. Wei, Y. D. Li, R. J. Wang, and Y. Zheng (2017). "Coulomb stress transfer and accumulation on the Sagaing Fault, Myanmar, over the past 110 years and its implications for seismic hazard". Geophysical Research Letters. 44 (10): 4781–4789. doi:10.1002/2017GL072770.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  16. ^ "Significant Earthquake: MYANMAR (BURMA): THARRAWADDY". NOAA.
  17. ^ Nutalaya; P.S. Sodsri; E.P. Arnold (1985). SEASEE Series on Seismology. Series on Seismology. Vol. II–Thailand. U.S. Geological Survey.
  18. ^ "M 7.6 - Myanmar". USGS.
  19. ^ ISC (2016), ISC-GEM Global Instrumental Earthquake Catalogue (1900–2012), Version 3.0, International Seismological Centre
  20. ^ "Event 914281 Myanmar-India border region". ISC: On-Line Bulletin. International Seismological Center. Retrieved 3 March 2021.
  21. ^ "Event 16958007 Myanmar". ISC: On-Line Bulletin. International Seismological Centre. Retrieved 3 March 2021.
  22. ^ "M 7.0 - Myanmar". USGS-ANSS. USGS. Retrieved 3 March 2021.
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