M4.6 earthquake 63 km NNE of Jiangyou, China

Wednesday, July 9, 2008, 23:19:51 UTC · 32.257°N, 105.056°E

A magnitude 4.6 earthquake struck 63 km NNE of Jiangyou, China on Wednesday, July 9, 2008, 23:19:51 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M4.8 on July 8, 2008.

Magnitude: 4.6; Light · mb
Depth: 10 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

120 tons of TNT

That is about 1/126 of the Hiroshima bomb. A magnitude 5.0 releases about 4 times more energy.

Tectonic setting

342 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 50 km

USGS lists 12 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.7 on August 1, 2008. 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 89 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 121,784 recorded deaths. The most severe:

2008M7.9
Sichuan Province
12 May 2008 · 212 km away · intensity IX
87,652 deaths$86 billion damagetsunami
1879M8.0
Gansu Province
1 Jul 1879 · 110 km away · intensity XI
22,000 deathsExtreme damage ($25M+)
1933M7.4
Sichuan Province
25 Aug 1933 · 135 km away · intensity X
9,300 deathsExtreme damage ($25M+)
1765M6.5
Gansu Province: Wushan, Gangu
2 Sep 1765 · 283 km away · intensity IX
2,068 deathsExtreme damage ($25M+)
1881M6.5
Gansu Province
20 Jul 1881 · 155 km away · intensity VIII
480 deathsSevere damage ($5–24M)
1936M6.0
Gansu Province
1 Aug 1936 · 224 km away · intensity VIII
115 deathsSevere damage ($5–24M)

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

Nearby trackers