Reviewed by USGSChina107y ago
M6.1 earthquake 138 km SSW of Yinchuan, China
Tuesday, December 28, 1920, 03:16:42 UTC · 37.418°N, 105.424°E
A magnitude 6.1 earthquake struck 138 km SSW of Yinchuan, China on Tuesday, December 28, 1920, 03:16:42 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M7.0 on December 25, 1920.
- Magnitude
- 6.1
- 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 earthquakeDashed circle: 100 km aftershock search area
In context
How big was it, and why here?
Energy released
20 kilotons of TNT
That is about the energy of the Hiroshima bomb. It released about 42 times the energy of a magnitude 5.0.
Tectonic setting
638 km
from the nearest mapped plate boundary, between the Amur and Eurasian 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 lists 1 M2.5+ earthquake within 100 km in the following 30 days; the largest was M6.0 on January 7, 1921. 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 3 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 8 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 362,942 recorded deaths. The most severe:
- 1920M8.3
Gansu Province, Shanxi Province
16 Dec 1920 · 91 km away · intensity XII
235,502 deaths$25 million damagetsunami
- 1718M7.5
Gansu Province
19 Jun 1718 · 270 km away · intensity X
73,000 deathsExtreme damage ($25M+)
- 1739M8.0
Ningxia
3 Jan 1739 · 190 km away · intensity X
50,000 deathsExtreme damage ($25M+)
- 1765M6.5
Gansu Province: Wushan, Gangu
2 Sep 1765 · 294 km away · intensity IX
2,068 deathsExtreme damage ($25M+)
- 1709M7.5
Ningxia
14 Oct 1709 · 11 km away · intensity X
2,032 deathsExtreme damage ($25M+)
- 1852M6.0
Ningxia
26 May 1852 · 22 km away · intensity VIII
300 deathsSevere damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.