Magnitude4.5

Reviewed by USGSIndia35y ago

M4.5 earthquake 41 km ENE of Uttarkāshi, India

Sunday, October 20, 1991, 04:20:28 UTC · 30.899°N, 78.832°E

A magnitude 4.5 earthquake struck 41 km ENE of Uttarkāshi, India on Sunday, October 20, 1991, 04:20:28 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M4.8 on October 19, 1991.

Magnitude
4.5
Light · mb
Depth
33 km
Shallow
Felt reports
0
Did You Feel It?
Est. shaking
—
No ShakeMap
PAGER alert
None
Not issued
Tsunami
No flag
USGS feed

Outlined circle: this earthquakeDashed circle: 50 km aftershock search area

In context

How big was it, and why here?

Energy released

85 tons of TNT

That is about 1/178 of the Hiroshima bomb. A magnitude 5.0 releases about 6 times more energy.

Tectonic setting

103 km

from the nearest mapped plate boundary, between the Eurasian and Indian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: shallow

33 km

Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.

Did You Feel It?

Where it was felt

No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.

I felt it — report to USGS ↗

USGS PAGER estimate

Who was exposed to shaking

USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.

After the main event

Aftershocks within 50 km

USGS lists 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.9 on October 20, 1991. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M51h6h1d3d7d14d30dMainshock M4.5
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 4.034 km E of Uttarkāshi, India35y ago · 14 km S of this epicenter
  2. 4.234 km ENE of Uttarkāshi, India35y ago · 8 km SW of this epicenter
  3. 4.924 km ENE of Uttarkāshi, India35y ago · 18 km SW of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 86 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 11 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 21,348 recorded deaths. The most severe:

  1. 1905M7.9

    Kangra

    4 Apr 1905 · 262 km away · intensity X

    19,000 deaths$25 million damagetsunami

  2. 1991M7.0

    Chamoli, Uttarkashi, New Delhi, Chandigarh

    19 Oct 1991 · 14 km away · intensity VIII

    2,000 deaths$60 million damage

  3. 1980M6.5

    Pithoragarh

    29 Jul 1980 · 261 km away

    200 deaths$245 million damage

  4. 1966M6.3

    Nepal-India

    27 Jun 1966 · 245 km away · intensity VIII

    80 deaths$1 million damage

  5. 1975M6.8

    Kashmir: Kinnaur District

    19 Jan 1975 · 178 km away

    47 deathsModerate damage ($1–5M)

  6. 1966M5.6

    N

    15 Aug 1966 · 245 km away

    15 deathsLimited damage (under $1M)

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers

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