Taskin Ahmed Kayum at 21:20, 15 March 2026

2026-03-15T21:20:20Z

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{{Short description|6.8 magnitude earthquake in India}}
{{Use dmy dates|date=November 2019}}
{{Use Indian English|date=June 2017}}
{{Infobox earthquake
| name = 1991 Uttarkashi earthquake
| timestamp = 1991-10-19 21:23:14
| anss-url = usp0004y1r
| isc-event = 317038
| image =
| alt =
| caption =
| map =
| map_alt =
| map_caption =
| map2 = {{Location map+ | India
|places =
{{Location map~|India|lat=31.55|long=74.34|label=Lahore|position=left|label_size=120|mark=Green pog.svg}}
{{Location map~|India|lat=28.61|long=77.23|label=Delhi|position=left|label_size=120|mark=Green pog.svg}}
{{Location map~|India|lat=27.7|long=85.33|label=Kathmandu|position=top|label_size=120|mark=Green pog.svg}}
{{Location map~|India|lat=30.75|long=78.82|mark=Bullseye1.png|marksize=40}}
| width = 250
| float = right
| caption =
| relief =yes}}
| local-date = 20 October 1991
| local-time = 02:53 [[Indian Standard Time]] ([[UTC+5:30]])
| duration = ~ 45 seconds<ref name=Kayal/>
| magnitude = 6.8 {{M|w|link=y}}<ref name="ISC-GEM"/>
| depth = {{convert|11.6|km|mi|0|abbr=on}}<ref name="ISC-GEM"/>
| location = {{coord|30.75|78.82|region:IN_type:event|display=inline,title}}<ref name="ISC-GEM"/>
| fault =
| type = [[Fault (geology)#Dip-slip faults|Reverse]]<ref name="PAGER-CAT"/>
| affected = [[Uttar Pradesh]] <br/> [[India]]
| damage = [[United States dollar|$]]60 million<ref name=NGDC/>
| intensity = {{MMI|9}}<ref name=Jain2/>
| pga = 0.31 ''[[Peak ground acceleration|g]]''<ref name=Jain2/>
| tsunami =
| landslide =
| foreshocks =
| aftershocks =
| casualties = 768–2,000 dead<ref name="PAGER-CAT"/> <br> 1,383–1,800 injured<ref name="PAGER-CAT"/>
}}

The '''1991 Uttarkashi earthquake''' (also known as the '''Garhwal earthquake''') occurred at 02:53:16 [[Indian Standard Time]] ([[UTC+05:30]]) on 20 October with a moment magnitude of 6.8 and a maximum Mercalli intensity of IX (''Violent''). This thrust event was instrumentally recorded and occurred along the Main Central Thrust in the [[Uttarkashi]] and Gharwal regions of the [[India]]n state of [[Uttarakhand]] (then still part of [[Uttar Pradesh]]). High intensity shaking resulted in the deaths of at least 768 people and the destruction of thousands of homes.

==Tectonic setting==
{{See also|Geology of the Himalaya}}

The [[Garhwal division]] in northern India, flanked by the [[Tons River]] to the west and the [[Alaknanda River]] to the east, is located at the boundary of the [[Indian plate|Indian]] and [[Eurasian plate|Eurasian]] tectonic plates. In the region, the Indian plate is moving northeastward at a rate of {{convert|5|cm|sp=us}} per year. The Main Central Thrust is the primary northwest-striking structure and dips to the north at 30–40°. The fault plane solutions from the parametric catalogs for the 1991 and [[1999 Chamoli earthquake|1999]] events showed low-angle thrust faulting with varying amounts of strike-slip movement.<ref>{{citation|title=Himalayan hazard study on the basis of stress and strain state of 1991 Uttarkashi earthquake using Coulomb stress transfer model|first1=D. K.|last1=Gupta|first2=D.|last2=Bhowmick|first3=P. N. S.|last3=Roy|year=2015|journal=Geomatics, Natural Hazards, and Risk|volume=6|number=2|pages=133, 140|doi=10.1080/19475705.2013.820797|bibcode=2015GNHR....6..131G |doi-access=free}}</ref>

==Earthquake==
Six three-axis accelerometers that were within {{convert|60|km|abbr=on}} captured the event, including two units that were close to the projection of the fault at the surface. Analysis of the data recorded by these devices revealed the distribution of slip, moment release over time, and the location of the maximum slip. The mechanism of the event was typical of the thrust system of the [[Himalayas]], with maximum slip ({{convert|1.5|m|abbr=on}}) occurring to the west and southwest of the hypocenter. Energy release began slowly and built to a crescendo four seconds after the initiation of the rupture.<ref>{{citation|title=Rupture history and seismotectonics of the 1991 Uttarkashi, Himalaya earthquake|first1=F.|last1=Cotton|first2=M.|last2=Campillo|first3=A.|last3=Deschamps|first4=B. K.|last4=Rastogi|year=1991|journal=Tectonophysics|volume=258|issue=1–4|pages=35–51|doi=10.1016/0040-1951(95)00154-9|bibcode=1996Tectp.258...35C}}</ref>

[[File:USGS Shakemap - 1991 Uttarkashi earthquake.jpg|thumb|USGS ShakeMap for the event]]

===Damage===
Scientists from the [[Indian Institute of Technology Kanpur|Indian Institute of Technology Kanpur (IITK)]] conducted a survey of the affected areas between 27 October and 4 November. Their work revealed that more than 300,000 people in 1,294 villages were affected by the shock. Stone masonry homes (that usually supported heavy roofs) fared badly in areas where high intensity shaking occurred. The United States' [[National Geophysical Data Center]] indicates that 7,500 homes were damaged and another 7,500 were destroyed while the IITK report shows that up to 42,400 houses were damaged.<ref name=NGDC/><ref name=Jain>{{citation|title=Garhwal Earthquake of Oct. 20, 1991|url=http://www.nicee.org/eqe-iitk/uploads/EQR_Uttarkashi.pdf|first1=Sudhir. K.|last1=Jain|first2=Ramesh P.|last2=Singh|first3=Vinay K.|last3=Gupta|first4=Amit|last4=Nagar|year=1992|publisher=National Information Centre of Earthquake Engineering|series=EERI Special Earthquake Report|volume=26|number=2|pages=1–3}}</ref>

The United States' [[National Geophysical Data Center]] and the Belgian [[Centre for Research on the Epidemiology of Disasters]]' EM-DAT database both list 1,500 fatalities for the event with EM-DAT also listing 1,383 injuries. The USGS's Preliminary Determination of Epicenters and the Utsu catalog both list 2,000 deaths and 1,800 injured.<ref name="PAGER-CAT"/>

===Intensity===
{{see also|Earthquake zones of India}}

{{harvnb|Jain|Singh|Gupta|Nagar|1992}} stated that the shock was generally moderate while further clarifying the intensities that were observed at specific locations. Ghansyali, Gongotri, and [[Tehri]] were listed as experiencing intensity VII (''Very strong'') shaking and Bhatwari, Budhakedar, Krishanpur, Mahinanda, Maneri, and [[Uttarkashi]] were listed as experiencing intensity VIII (''Severe'') shaking. In a report that documented the study of strong motion recordings of the event, {{harvnb|Jain|Das|1993}} clarified that while Bhatwari and Uttarkashi experienced intensity VIII shaking at distances of {{convert|25|km|abbr=on}} and {{convert|40|km|abbr=on}} respectively, there was a small 20 km square mile area that experienced a maximum intensity of IX (''Violent'').<ref name=Jain2>{{citation|title=Analysis of Strong Motion Records from Uttarkashi Earthquake for Assessment of Code Provisions for Different Seismic Zones|url=http://www.iitk.ac.in/nicee/skj/Research_Papers/ANALYSIS%20OF%20STRONG%20MOTION%20RECORDS%20FROM%20UTTARKASHI_39.pdf|first1=Sudhir K.|last1=Jain|first2=Satrajit|last2=Das|date=1993|journal=Earthquake Spectra|volume=9|number=4|pages=739, 742|doi=10.1193/1.1585738|bibcode=1993EarSp...9..739J |s2cid=128901914}}</ref><ref name=Jain/>

==See also==
*[[List of earthquakes in 1991]]
*[[List of earthquakes in India]]
*[[1999 Chamoli earthquake]]
*[[Tehri Dam]]

==References==
<references>
<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|archive-url=https://web.archive.org/web/20060929000601/http://www.ngdc.noaa.gov/nndc/struts/form?t=101650&s=1&d=1|url-status=dead|archive-date=29 September 2006|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="PAGER-CAT">{{citation|title=PAGER-CAT Earthquake Catalog|url=https://earthquake.usgs.gov/static/lfs/data/pager/catalogs/PAGER_CAT_v2.zip|date=4 September 2009|publisher=United States Geological Survey|series=Version 2008_06.1}}</ref>
<ref name=Kayal>{{citation|title= Precursor seismicity, foreshocks and aftershocks of the Uttarkashi earthquake of October 20, 1991 at Garhwal Himalaya|first=J. R.|last=Kayal|year=2015|journal=Tectonophysics|volume=263|issue=1–3|page=339|doi=10.1016/S0040-1951(97)81488-6|bibcode=1996Tectp.263..339K}}</ref>
</references>

==Further reading==
*{{citation|title=Seismotectonics of the 20 October 1991 Uttarkashi earthquake in Garhwal, Himalaya, North India|url=http://cat.inist.fr/?aModele=afficheN&cpsidt=4032621|first1=V. C.|last1=Thakur|first2=K.|last2=Sushil|year=1994|journal=Terra Nova|volume=6|number=1|pages=90–94|doi=10.1111/j.1365-3121.1994.tb00637.x|bibcode=1994TeNov...6...90T|url-access=subscription}}
*{{citation|title=The Uttarkashi earthquake of 20 October: Implications and lessons|last1=Valdiya|first1=K. S.|journal=Current Science|year=1991|volume=61|issue=12|pages=801–803|jstor=24095349}}

==External links==
*[https://earthquake.usgs.gov/earthquakes/eventpage/usp0004y1r#executive M 6.8 – Uttaranchal, India] – [[United States Geological Survey]]
*[https://web.archive.org/web/20161111122940/https://www.himalayanclub.org/hj/62/5/the-great-himalayan-earthquakes/ The Great Himalayan Earthquakes] – ''[[Himalayan Journal]]''
*{{EQ-isc-link|317038}}

{{Disasters in Uttarakhand}}
{{Earthquakes in 1991}}
{{Earthquakes in India}}
{{Himalayan earthquakes}}

[[Category:1991 disasters in India|Uttarkashi Earthquake, 1991]]
[[Category:1991 earthquakes|Uttarkashi]]
[[Category:Disasters in Uttarakhand]]
[[Category:Earthquakes in India]]
[[Category:History of Uttarakhand (1947–present)]]
[[Category:October 1991 in India]]
[[Category:Uttarkashi district]]
[[Category:1990s in Uttar Pradesh]]

1991 Uttarkashi earthquake - Revision history

Taskin Ahmed Kayum at 21:20, 15 March 2026