Reviewed by USGSIndia98y ago
M6.1 earthquake 211 km S of Port Blair, India
Thursday, August 1, 1929, 05:01:50 UTC · 9.757°N, 92.872°E
A magnitude 6.1 earthquake struck 211 km S of Port Blair, India on Thursday, August 1, 1929, 05:01:50 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M6.6 on March 5, 1921.
- Magnitude
- 6.1
- Strong · mw
- Depth
- 35 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
23 kilotons of TNT
That is about 2 times the Hiroshima bomb. It released about 48 times the energy of a magnitude 5.0.
Tectonic setting
118 km
from the nearest mapped plate boundary, between the Caribbean and Cocos plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
35 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 100 km
USGS has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 9 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 6.6249 km NW of Sabang, IndonesiaMarch 5, 1921 · 275 km S of this epicenter
- 6.3273 km SSE of Port Blair, IndiaOctober 21, 1916 · 93 km SE of this epicenter
- 6.2Nicobar Islands, India regionAugust 12, 1915 · 294 km SW of this epicenter
- 6.0119 km SW of Port Blair, IndiaMay 13, 1925 · 139 km NW of this epicenter
- 6.097 km ESE of Port Blair, IndiaOctober 11, 1914 · 202 km NE of this epicenter
- 5.978 km S of Port Blair, IndiaJune 28, 1925 · 134 km N of this epicenter
- 5.746 km N of Bamboo Flat, IndiaMay 19, 1928 · 262 km N of this epicenter
- 5.6227 km NW of Sabang, IndonesiaMay 17, 1927 · 296 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 2 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 · 146 km away
Severe damage ($5–24M)tsunami
- 1847
Little Nicobar Island
31 Oct 1847 · 283 km away · intensity X
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.