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{{Short description|Seismic event}}
{{Infobox earthquake
|title= 1881 Nicobar Islands earthquake
|pre-1900 = yes
|local-date= {{Start-date|31 December 1881}}
|local-time= 07:49
|map2 = {{Location map+ | India
|places =
{{Location map~|India|lat=12.86|long=74.83|label=Mangalore|position=left|mark=Green pog.svg}}
{{Location map~|India|lat=6.93|long=79.84|label=Colombo|position=left|mark=Green pog.svg}}
{{Location map~|India|lat=13.08|long=80.27|label=Chennai|mark=Green pog.svg}}
{{Location map~|India|lat=22.57|long=88.37|label=Kolkata|position=left|mark=Green pog.svg}}
{{Location map~|India|lat=5.55|long=95.32|label=Banda Aceh|position=left|mark=Green pog.svg}}
{{Location map~|India|lat=27.7|long=85.33|label=Kathmandu|position=top|mark=Green pog.svg}}
{{Location map~|India|lat=9.25|long=92.7|mark=Bullseye1.png|marksize=40}}
| width= 250
| float=right
| caption=
| relief=yes}}
|magnitude = 7.9 [[Moment magnitude scale|M<sub>w</sub>]]
|depth=
|location={{coord|9.25|92.70|display=inline,title}}<ref name="Bilham"/>
|countries affected = [[India]], [[Andaman and Nicobar Islands]]
|tsunami = yes
|intensity = {{EMS-98|VII}}<ref name=Martin/>
|casualties = none reported
}}

The '''1881 Nicobar Islands earthquake''' occurred at about 07:49 local time (01:49 [[Coordinated universal time|UTC]]) on 31 December, with an [[epicenter|epicentre]] beneath [[Car Nicobar]]. It occurred as two separate [[earthquake#Rupture dynamics|ruptures]], the largest of which had an estimated magnitude of 7.9 on the [[moment magnitude scale]] and triggered a [[tsunami]] that was observed around the [[Bay of Bengal]]. It is probably the earliest [[earthquake]] for which rupture parameters have been estimated instrumentally.<ref name="Ortiz">{{cite journal|last=Ortiz|first=M.|author2=Bilham R.|year=2003|title=Source area and rupture parameters of the 31 December 1881 Mw = 7.9 Car Nicobar earthquake estimated from tsunamis recorded in the Bay of Bengal|journal=Journal of Geophysical Research|publisher=American Geophysical Union|volume=108|issue=B4|page=2215|doi=10.1029/2002JB001941|url=http://ciresweb.colorado.edu/~bilham/Andaman.pdf|bibcode=2003JGRB..108.2215O}}</ref>

==Tectonic setting==
The [[Nicobar Islands]] are a series of volcanic islands that are part of an active [[volcanic arc]], formed above the [[subduction|subduction zone]] where the [[Indo-Australian plate]] passes beneath the [[Burma plate]]. The convergence along this plate boundary is highly oblique, with the plate vector running at a low angle to the boundary. Most of the strike-slip component of the convergence is accommodated by the [[Great Sumatran fault]], which passes northwards into the [[Andaman Sea]] [[Mid-ocean ridge|spreading centre]].<ref name="Ortiz"/> This plate boundary has been the location of many historical [[megathrust earthquake]]s. The 1881 rupture area lies almost entirely within that for the {{M|w|link=y}} 9.2 [[2004 Indian Ocean earthquake]], while rupturing less than a third of its down-dip width.<ref name="Bilham"/>

==Damage==
The Andaman and Nicobar Islands suffered some damage, although the only masonry buildings affected were in [[Port Blair]], including an infantry barrack and a chimney, both of which suffered severe cracking. On Car Nicobar, the coconut plantations and native huts were extensively damaged and [[sand volcano]]es were observed.<ref name="Ortiz"/> There were no reported casualties associated with either the earthquake or the subsequent tsunami.<ref name="NGDC">{{citation|url=https://www.ngdc.noaa.gov/hazel/view/hazards/earthquake/event-more-info/2310|title=Significant Earthquake Information|last=National Geophysical Data Center / World Data Service (NGDC/WDS): NCEI/WDS Global Significant Earthquake Database. NOAA National Centers for Environmental Information|year=1972 |publisher=NOAA National Centers for Environmental Information |accessdate=2 August 2022|doi=10.7289/V5TD9V7K}}</ref>

==Characteristics==

{| class="wikitable" style="float: right; text-align: center; font-size:90%;"
|-
| colspan="2" style="text-align: center;" | Selected [[European macroseismic scale|EMS-98]] intensities
|-
! Intensity !! Locations
|-
| {{EMS-98|7}}
| [[Car Nicobar]]
|-
| {{EMS-98|6}}
| [[Port Blair]]
|-
| {{EMS-98|5}}
| [[Chennai]]
|-
| {{EMS-98|4}}
| [[Banda Aceh]], [[Colombo]]
|-
| {{EMS-98|3}}
| [[Kolkata]]
|-
|-
| {{EMS-98|2}}
| [[Kathmandu]], [[Mangalore]]
|-
| colspan="3" style="text-align: center;" | <small>{{harvnb|Martin|Szeliga|2010}}</small>
|}

===Earthquake===
The earthquake was very widely felt with reports from many parts of mainland [[India]], [[Burma]] and [[Sumatra]], a total area of {{convert|2000000|sqmi|km2}}.<ref name="Ortiz"/> The rupture area, and therefore the magnitude, has been calculated by modelling the observed tsunami arrival times and heights. Two rupture areas have been identified.<ref name="Bilham"/> The larger, and more southerly, measured 150 km x 60 km dipping about 20° to the east with a displacement of {{convert|2.7|m|ft}} and a smaller area to the north dipping 15° to the east with a displacement of {{convert|0.9|m|ft|abbr=on}}. The larger gives an estimated {{M|w|link=y}} 7.9 event and the smaller a {{M|w}} 7.0 event.<ref name="Bilham">{{cite journal|last=Bilham|first=R.|author2=Engdahl R., Feldl N. & Satyabala S.P.|year=2005|title=Partial and Complete Rupture of the Indo-Andaman Plate Boundary 1847–2004|journal=Seismological Research Letters|volume=76|issue=3|pages=299–311|doi=10.1785/gssrl.76.3.299|bibcode=2005SeiRL..76..299B |url=http://cires.colorado.edu/~bilham/IndonesiAndaman2004_files/AndamanSRL4Mar.pdf|accessdate=20 November 2010}}</ref>

===Tsunami===
The tsunami was recorded by eleven of a series of continuous [[tide gauge]]s around the Bay of Bengal that had recently been deployed by the [[Great Trigonometric Survey]] of India.<ref name="Ortiz"/> The ten gauges on the Indian mainland were synchronised using a telegraph to Madras ([[Chennai]]) time, while that at Port Blair was set by a [[chronometer watch|chronometer]] linked to local time. The maximum recorded wave height was {{convert|1.22|m|ft|abbr=on}} at [[Nagapattinam]].<ref name="Ortiz"/>

==See also==
* [[List of historical earthquakes]]
* [[List of tsunamis]]

==References==
{{Reflist|refs=
<ref name=Martin>{{citation|title=A Catalog of Felt Intensity Data for 570 Earthquakes in India from 1636 to 2009|url=http://www.bssaonline.org/content/100/2/562.abstract|first1=S.|last1=Martin|first2=W.|last2=Szeliga|year=2010|journal=Bulletin of the Seismological Society of America|publisher=[[Seismological Society of America]]|series=Electronic Supplement (table S2)|volume=100|number=2|pages=562–569|doi=10.1785/0120080328|bibcode=2010BuSSA.100..562M|access-date=2017-02-16|archive-date=2016-11-12|archive-url=https://web.archive.org/web/20161112172909/http://www.bssaonline.org/content/100/2/562.abstract|url-status=dead|url-access=subscription}}</ref>
}}

{{Earthquakes in India}}

[[Category:Earthquakes in India]]
[[Category:1881 earthquakes|Nicobar Islands Earthquake, 1881]]
[[Category:History of the Andaman and Nicobar Islands]]
[[Category:1881 in India]]
[[Category:19th-century tsunamis]]
[[Category:1881 natural disasters]]
[[Category:December 1881]]
[[Category:Tsunamis in India]]
[[Category:Megathrust earthquakes in India]]
[[Category:Tsunamis in Myanmar]]
[[Category:Tsunamis in Thailand]]
[[Category:1880s disasters in Asia]]
[[Category:19th-century disasters in India]]

1881 Nicobar Islands earthquake - Revision history

Sergqpm at 09:15, 28 May 2025