Magnitude6.6

Reviewed by USGSChina75y ago

M6.6 earthquake 59 km N of Xichang, China

Tuesday, September 30, 1952, 12:52:03 UTC · 28.430°N, 102.250°E

A magnitude 6.6 earthquake struck 59 km N of Xichang, China on Tuesday, September 30, 1952, 12:52:03 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M7.3 on May 25, 1948.

Magnitude
6.6
Strong · mw
Depth
10 km
Shallow
Felt reports
0
Did You Feel It?
Est. shaking
VIII
Severe (ShakeMap)
PAGER alert
None
Not issued
Tsunami
No flag
USGS feed

Outlined circle: this earthquakeColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

128 kilotons of TNT

That is about 9 times the Hiroshima bomb. It released about 269 times the energy of a magnitude 5.0.

Tectonic setting

270 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 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 27 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 33 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 25,299 recorded deaths. The most severe:

  1. 1850M7.5

    Sichuan: Xichang

    12 Sep 1850 · 70 km away · intensity X

    20,650 deathsExtreme damage ($25M+)

  2. 1917M6.8

    Yunnan Province

    30 Jul 1917 · 178 km away · intensity IX

    1,800 deathsExtreme damage ($25M+)

  3. 1948M7.3

    Sichuan Province

    25 May 1948 · 208 km away · intensity X

    800 deathsSevere damage ($5–24M)

  4. 1786M7.5

    Sichuan Province: S Of Kangding

    1 Jun 1786 · 153 km away · intensity IX

    435 deathsSevere damage ($5–24M)

  5. 1893M6.8

    Sichuan Province

    29 Aug 1893 · 241 km away · intensity IX

    288 deathsSevere damage ($5–24M)

  6. 1792M6.0

    Sichuan Province: N Of Qianning

    7 Sep 1792 · 295 km away · intensity VIII

    205 deathsModerate damage ($1–5M)

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

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