M6.8 earthquake 72 km WSW of Xunchang, China

Friday, May 10, 1974, 19:25:15 UTC · 28.243°N, 104.015°E

A magnitude 6.8 earthquake struck 72 km WSW of Xunchang, China on Friday, May 10, 1974, 19:25:15 UTC, at a depth of 11.0 km (shallow). It is the strongest earthquake within 300 km since an M7.1 on April 14, 1955.

Magnitude: 6.8; Strong · ms
Depth: 11 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

239 kilotons of TNT

That is about 16 times the Hiroshima bomb. It released about 501 times the energy of a magnitude 5.0.

Tectonic setting

99 km

from the nearest mapped plate boundary, between the Eurasian and Yangtze plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: shallow

11 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 6 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M5.2 on June 5, 1974. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 56 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 32 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 43,558 recorded deaths. The most severe:

1850M7.5
Sichuan: Xichang
12 Sep 1850 · 175 km away · intensity X
20,650 deathsExtreme damage ($25M+)
1974M7.1
Yunnan And Sichuan Provinces, Chao-T'Ung
10 May 1974 · 1 km away
20,000 deathsSevere damage ($5–24M)
1917M6.8
Yunnan Province
30 Jul 1917 · 27 km away · intensity IX
1,800 deathsExtreme damage ($25M+)
1786M7.5
Sichuan Province: S Of Kangding
1 Jun 1786 · 254 km away · intensity IX
435 deathsSevere damage ($5–24M)
1932M6.0
Sichuan Province
6 Mar 1932 · 298 km away · intensity VIII
200 deathsLimited damage (under $1M)
1933M5.0
Sichuan Province
20 Sep 1933 · 203 km away · intensity VI
200 deathsLimited damage (under $1M)

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers