Reviewed by USGSIndia region54y ago
M4.8 earthquake in Nicobar Islands, India region
Saturday, April 7, 1973, 03:14:46 UTC · 6.871°N, 91.383°E
A magnitude 4.8 earthquake struck in Nicobar Islands, India region on Saturday, April 7, 1973, 03:14:46 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M6.6 on April 7, 1973.
- Magnitude
- 4.8
- 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 earthquake
In context
How big was it, and why here?
Energy released
239 tons of TNT
That is about 1/63 of the Hiroshima bomb. A magnitude 5.0 releases about 2 times more energy.
Tectonic setting
92 km
from the nearest mapped plate boundary, between the Indian and Burma plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
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 has not published any M2.5+ earthquake within 50 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 22 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.0190 km WNW of Sabang, IndonesiaMay 17, 1955 · 274 km E of this epicenter
- 6.8238 km WNW of Sabang, IndonesiaJanuary 20, 1917 · 232 km E of this epicenter
- 6.6Nicobar Islands, India regionApril 7, 1973 · 11 km N of this epicenter
- 6.6249 km NW of Sabang, IndonesiaMarch 5, 1921 · 256 km E of this epicenter
- 6.5253 km WNW of Sabang, IndonesiaNovember 21, 1907 · 195 km E of this epicenter
- 6.3184 km W of Banda Aceh, IndonesiaNovember 25, 1935 · 288 km SE of this epicenter
- 6.3off the west coast of northern SumatraNovember 30, 1937 · 205 km S of this epicenter
- 6.3Nicobar Islands, India regionSeptember 15, 1964 · 289 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 3 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1881M7.9
Andaman I,Nicobar I
31 Dec 1881 · 217 km away
Severe damage ($5–24M)tsunami
- 1847
Little Nicobar Island
31 Oct 1847 · 257 km away · intensity X
Limited damage (under $1M)tsunami
- 1955M7.3
Little Nicobar Island
17 May 1955 · 292 km away
tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.