Reviewed by USGSMexico41y ago
M5.4 earthquake 15 km WSW of Papanoa, Mexico
Saturday, September 28, 1985, 03:52:46 UTC · 17.274°N, 101.182°W
A magnitude 5.4 earthquake struck 15 km WSW of Papanoa, Mexico on Saturday, September 28, 1985, 03:52:46 UTC, at a depth of 33.0 km (shallow). It is the strongest earthquake within 300 km since an M5.7 on September 25, 1985.
- Magnitude
- 5.4
- Moderate · mw
- 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: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
2 kilotons of TNT
That is about 1/8 of the Hiroshima bomb. It released about 4 times the energy of a magnitude 5.0.
Tectonic setting
48 km
from the nearest mapped plate boundary, between the Cocos and North American plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
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 75 km
USGS lists 4 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M4.3 on October 3, 1985. 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 143 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.01985 Michoacan, Mexico EarthquakeSeptember 19, 1985 · 176 km NW of this epicenter
- 7.621 km ESE of Coalcomán de Vázquez Pallares, MexicoApril 15, 1941 · 247 km NW of this epicenter
- 7.68 km ENE of Apantla, MexicoJuly 28, 1957 · 223 km E of this epicenter
- 7.619 km W of Arteaga, MexicoJune 7, 1911 · 182 km NW of this epicenter
- 7.612 km SSE of Vallecitos de Zaragoza, MexicoMarch 14, 1979 · 61 km N of this epicenter
- 7.67 km N of Pantla, MexicoSeptember 21, 1985 · 77 km NW of this epicenter
- 7.525 km S of Tetitlán, MexicoDecember 16, 1911 · 67 km SE of this epicenter
- 7.527 km SSE of San Andrés Playa Encantada (El Podrido), MexicoJuly 30, 1909 · 198 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 50 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 10,048 recorded deaths. The most severe:
- 1985M8.1
Michoacan: Mexico City
19 Sep 1985 · 176 km away · intensity IX
9,500 deaths$4.0 billion damagetsunami
- 1912M6.7
Central, Acambay, Tixmadeje
19 Nov 1912 · 289 km away
202 deathsSevere damage ($5–24M)
- 1941M7.6
Michoacan, Colima, Jalisco
15 Apr 1941 · 247 km away · intensity VII
84 deaths$2 million damagetsunami
- 1964M7.3
Guerrero
6 Jul 1964 · 114 km away
78 deathsSevere damage ($5–24M)
- 1957M7.9
Acapulco,Mexico City
28 Jul 1957 · 238 km away · intensity VII
65 deaths$25 million damagetsunami
- 1973M7.5
S, Farias, Tecoman
30 Jan 1973 · 235 km away
56 deathsModerate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.