Reviewed by USGSPeru35y ago
M4.5 earthquake 27 km NNW of Moyobamba, Peru
Saturday, May 25, 1991, 22:25:10 UTC · 5.812°S, 77.086°W
A magnitude 4.5 earthquake struck 27 km NNW of Moyobamba, Peru on Saturday, May 25, 1991, 22:25:10 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M4.9 on May 18, 1991.
- Magnitude
- 4.5
- Light · mb
- Depth
- 33 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
85 tons of TNT
That is about 1/178 of the Hiroshima bomb. A magnitude 5.0 releases about 6 times more energy.
Tectonic setting
177 km
from the nearest mapped plate boundary, between the Sunda and Australian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
33 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 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M4.8 on May 28, 1991. 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 132 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.516 km W of Barranca, PeruSeptember 28, 1906 · 115 km N of this epicenter
- 7.323 km N of Bellavista, PeruMay 14, 1928 · 179 km W of this epicenter
- 7.111 km NE of Rioja, PeruApril 5, 1991 · 19 km S of this epicenter
- 7.115 km SSW of Huabal, PeruJuly 18, 1928 · 210 km W of this epicenter
- 7.092 km NNE of La Peca, PeruApril 12, 1983 · 156 km NW of this epicenter
- 6.86 km SSW of Quiches, PeruNovember 10, 1946 · 297 km S of this epicenter
- 6.8109 km W of Alianza Cristiana, PeruNovember 23, 1986 · 277 km N of this epicenter
- 6.848 km NNE of Segunda Jerusalén - Azunguillo, PeruJune 19, 1968 · 27 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 11 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 323 recorded deaths. The most severe:
- 1990M6.5
Moyabamba-Riojo
30 May 1990 · 28 km away · intensity VI
200 deaths$1 million damage
- 1991M6.7
Rioja, Moyobamba, Nueva Cajamarca
5 Apr 1991 · 19 km away · intensity VII
53 deathsSevere damage ($5–24M)
- 1928M7.3
Chacahpoyas,Huancabamba,Cajamarca,Pinpincos
14 May 1928 · 180 km away · intensity X
29 deathsSevere damage ($5–24M)
- 1968M6.8
San Martin,Moyobamba,Yantalo,Rioja,Lamas
19 Jun 1968 · 22 km away
15 deathsUnder $1 million damage
- 1972M6.1
Juanjui
20 Mar 1972 · 114 km away · intensity IX
12 deaths$20 million damage
- 1983M6.5
Chimbote
12 Apr 1983 · 156 km away
10 deathsUnder $1 million damage
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.