Reviewed by USGSChina72y ago
M6.7 earthquake 11 km SE of Dadukou, China
Friday, September 23, 1955, 15:06:20 UTC · 26.467°N, 101.780°E
A magnitude 6.7 earthquake struck 11 km SE of Dadukou, China on Friday, September 23, 1955, 15:06:20 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M6.8 on March 16, 1925.
- Magnitude
- 6.7
- Strong · mw
- Depth
- 10 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- VII
- Very strong (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
169 kilotons of TNT
That is about 11 times the Hiroshima bomb. It released about 355 times the energy of a magnitude 5.0.
Tectonic setting
346 km
from the nearest mapped plate boundary, between the Eurasian and Yangtze plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
10 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 lists 1 M2.5+ earthquake within 100 km in the following 30 days; the largest was M5.9 on September 28, 1955. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 21 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 6.824 km NE of Dali, ChinaMarch 16, 1925 · 161 km SW of this epicenter
- 6.833 km WSW of Yuxi, ChinaDecember 21, 1913 · 249 km S of this epicenter
- 6.659 km N of Xichang, ChinaSeptember 30, 1952 · 223 km N of this epicenter
- 6.438 km SSW of Lijiang, ChinaDecember 21, 1951 · 176 km W of this epicenter
- 6.350 km NNW of Lijiang, ChinaJune 7, 1933 · 198 km NW of this epicenter
- 6.260 km WNW of Dadukou, ChinaJune 7, 1955 · 70 km W of this epicenter
- 6.245 km SSW of Yuxi, ChinaJanuary 12, 1934 · 288 km S of this epicenter
- 6.110 km WNW of Lijiang, ChinaOctober 15, 1925 · 172 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 50 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 41,906 recorded deaths. The most severe:
- 1850M7.5
Sichuan: Xichang
12 Sep 1850 · 157 km away · intensity X
20,650 deathsExtreme damage ($25M+)
- 1833M8.0
Yunnan Province
6 Sep 1833 · 186 km away · intensity XI
6,700 deathsExtreme damage ($25M+)tsunami
- 1925M6.9
Yunnan Province: Talifu
16 Mar 1925 · 161 km away
5,800 deathsExtreme damage ($25M+)
- 1713M6.8
Yunnan Province: S Of Xundian
26 Feb 1713 · 185 km away · intensity IX
2,100 deathsExtreme damage ($25M+)
- 1917M6.8
Yunnan Province
30 Jul 1917 · 278 km away · intensity IX
1,800 deathsExtreme damage ($25M+)
- 1763M6.5
Yunnan Province
30 Dec 1763 · 262 km away · intensity VIII
1,000 deathsExtreme damage ($25M+)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.