M5.0 earthquake western Indian-Antarctic Ridge

Saturday, April 30, 1988, 17:58:36 UTC · 50.019°S, 115.559°E

A magnitude 5.0 earthquake struck western Indian-Antarctic Ridge on Saturday, April 30, 1988, 17:58:36 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M5.7 on March 5, 1988.

Magnitude: 5.0; Moderate · 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: 75 km aftershock search area

In context

How big was it, and why here?

Energy released

477 tons of TNT

That is about 1/32 of the Hiroshima bomb. Each whole step in magnitude is about 32 times more energy.

Tectonic setting

7 km

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

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 75 km

USGS lists 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M5.7 on May 5, 1988. 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.

5.7western Indian-Antarctic Ridge38y ago · 22 km NW of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 13 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

Nearby trackers