Reviewed by USGSChina87y ago
M6.2 earthquake 79 km SSW of Nagqu, China
Friday, October 4, 1940, 04:35:55 UTC · 30.851°N, 91.658°E
A magnitude 6.2 earthquake struck 79 km SSW of Nagqu, China on Friday, October 4, 1940, 04:35:55 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M6.2 on September 3, 1940.
- Magnitude
- 6.2
- Strong · mw
- Depth
- 15 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
31 kilotons of TNT
That is about 2 times the Hiroshima bomb. It released about 65 times the energy of a magnitude 5.0.
Tectonic setting
422 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
15 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 20 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.3200 km NW of Dêqên, ChinaDecember 15, 1934 · 241 km W of this epicenter
- 6.6147 km NW of Dêqên, ChinaOctober 8, 1924 · 197 km W of this epicenter
- 6.2161 km NNE of Nagqu, ChinaJune 23, 1934 · 240 km NE of this epicenter
- 6.2100 km NE of Dêqên, ChinaSeptember 3, 1940 · 41 km S of this epicenter
- 6.275 km NNW of Dêqên, ChinaOctober 14, 1921 · 126 km W of this epicenter
- 6.1237 km NW of Nagqu, ChinaAugust 31, 1925 · 273 km NW of this epicenter
- 6.1249 km NW of Nagqu, ChinaDecember 2, 1938 · 289 km NW of this epicenter
- 5.929 km NNW of Dêqên, ChinaAugust 13, 1924 · 119 km SW 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, which together caused about 270 recorded deaths. The most severe:
- 1915M7.0
Tibet (Xizang Province)
3 Dec 1915 · 151 km away · intensity IX
170 deathsModerate damage ($1–5M)
- 1806M7.7
Tibet (Xizang Province): Shannan (Lhoka)
11 Jun 1806 · 263 km away
100 deathsModerate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.