M5.5 earthquake 16 km S of Emiliano Zapata, Mexico

Wednesday, October 18, 1995, 23:02:08 UTC · 19.243°N, 104.989°W

A magnitude 5.5 earthquake struck 16 km S of Emiliano Zapata, Mexico on Wednesday, October 18, 1995, 23:02:08 UTC, at a depth of 20.2 km (shallow). It is the strongest earthquake within 300 km since an M6.0 on October 12, 1995.

Magnitude: 5.5; Moderate · mw
Depth: 20 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: V; Moderate (ShakeMap)
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 75 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

3 kilotons of TNT

That is about 1/6 of the Hiroshima bomb. It released about 6 times the energy of a magnitude 5.0.

Tectonic setting

59 km

from the nearest mapped plate boundary, between the North American and Rivera plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: shallow

20 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 6 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M4.6 on November 3, 1995. 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 164 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 14,252 recorded deaths. The most severe:

1985M8.1
Michoacan: Mexico City
19 Sep 1985 · 284 km away · intensity IX
9,500 deaths$4.0 billion damagetsunami
1806M7.5
Jalisco,Oaxaca,Michoacan
25 Mar 1806 · 131 km away · intensity VIII
2,000 deathsExtreme damage ($25M+)
1818M8.2
Morelos-Guerrero,Mexico City,Guadalajara
31 May 1818 · 111 km away · intensity X
2,000 deathsSevere damage ($5–24M)tsunami
1932M8.1
Near Coast Of Jalisco
3 Jun 1932 · 120 km away · intensity X
400 deathsSevere damage ($5–24M)tsunami
1941M7.6
Michoacan, Colima, Jalisco
15 Apr 1941 · 219 km away · intensity VII
84 deaths$2 million damagetsunami
1932M7.7
Central
22 Jun 1932 · 64 km away
75 deathsSevere damage ($5–24M)tsunami

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

Nearby trackers