Reviewed by USGSIndia21y ago
M4.3 earthquake 252 km S of Port Blair, India
Sunday, January 23, 2005, 03:47:08 UTC · 9.405°N, 93.090°E
A magnitude 4.3 earthquake struck 252 km S of Port Blair, India on Sunday, January 23, 2005, 03:47:08 UTC, at a depth of 30.0 km (shallow).
- Magnitude
- 4.3
- Light · mb
- Depth
- 30 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
43 tons of TNT
That is about 1/354 of the Hiroshima bomb. A magnitude 5.0 releases about 11 times more energy.
Tectonic setting
108 km
from the nearest mapped plate boundary, between the Sunda and Burma plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
30 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 5 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.8 on January 23, 2005. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.6258 km S of Port Blair, India21y ago · 11 km SW of this epicenter
- 4.2241 km SSE of Port Blair, India21y ago · 39 km NE of this epicenter
- 4.3246 km SSE of Port Blair, India21y ago · 19 km NE of this epicenter
- 4.3274 km S of Port Blair, India21y ago · 43 km SW of this epicenter
- 4.8250 km SSE of Port Blair, India21y ago · 13 km E of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 323 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.2284 km WNW of Sabang, IndonesiaDecember 26, 2004 · 278 km S of this epicenter
- 7.0190 km WNW of Sabang, IndonesiaMay 17, 1955 · 299 km S of this epicenter
- 6.8238 km WNW of Sabang, IndonesiaJanuary 20, 1917 · 268 km S of this epicenter
- 6.6Nicobar Islands, India regionDecember 26, 2004 · 98 km SW of this epicenter
- 6.6249 km NW of Sabang, IndonesiaMarch 5, 1921 · 231 km S of this epicenter
- 6.5171 km S of Port Blair, IndiaApril 19, 1936 · 88 km NW of this epicenter
- 6.3273 km SSE of Port Blair, IndiaOctober 21, 1916 · 57 km E of this epicenter
- 6.3Nicobar Islands, India regionOctober 25, 1970 · 94 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 5 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1941M8.0
Andaman Islands,Madras; Sri Lanka: Colombo
26 Jun 1941 · 286 km away
Extreme damage ($25M+)tsunami
- 1881M7.9
Andaman I,Nicobar I
31 Dec 1881 · 122 km away
Severe damage ($5–24M)tsunami
- 1982M6.3
Little Nicobar Island
20 Jan 1982 · 291 km away · intensity VIII
Moderate damage ($1–5M)
- 2005M7.2
Andaman Islands, Nicobar Islands
24 Jul 2005 · 192 km away
Limited damage (under $1M)
- 1847
Little Nicobar Island
31 Oct 1847 · 239 km away · intensity X
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.