QuakeScout
Magnitude3.8

Reviewed by USGSTonga29y ago

M3.8 earthquake 297 km WNW of Haveluloto, Tonga

Friday, May 2, 1997, 01:57:55 UTC · 20.182°S, 177.878°W

A magnitude 3.8 earthquake struck 297 km WNW of Haveluloto, Tonga on Friday, May 2, 1997, 01:57:55 UTC, at a depth of 500.0 km (deep).

Magnitude
3.8
Minor · mb
Depth
500 km
Deep
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

8 tons of TNT

That is about 1/1,992 of the Hiroshima bomb. A magnitude 5.0 releases about 63 times more energy.

Tectonic setting

175 km

from the nearest mapped plate boundary, between the Niuafo'ou and Australian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: deep

500 km

Deep earthquakes (over 300 km) happen deep inside subducting plates. They rarely cause damage, but can be felt faintly over very large distances.

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 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.2 on May 19, 1997. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M41h6h1d3d7d14d30dMainshock M3.8
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 4.2Fiji region29y ago · 12 km W of this epicenter
  2. 4.1Fiji region29y ago · 25 km SW of this epicenter
  3. 4.0Fiji region29y ago · 25 km NW of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 1,219 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 7.8159 km W of Pangai, TongaDecember 14, 1950 · 216 km E of this epicenter
  2. 7.8Fiji regionJanuary 1, 1919 · 98 km N of this epicenter
  3. 7.6178 km E of Levuka, FijiFebruary 22, 1909 · 251 km NW of this epicenter
  4. 7.6240 km E of Levuka, FijiMarch 9, 1994 · 245 km N of this epicenter
  5. 7.5262 km WNW of Haveluloto, TongaMay 21, 1962 · 45 km E of this epicenter
  6. 7.4227 km E of Levuka, FijiAugust 21, 1910 · 272 km N of this epicenter
  7. 7.4Fiji regionSeptember 28, 1957 · 63 km SW of this epicenter
  8. 7.4Fiji regionAugust 5, 1996 · 72 km SW of this epicenter

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. The most severe:

  1. 1937M8.1

    Fiji Islands

    16 Apr 1937 · 173 km away

  2. 1909M7.8

    Fiji Islands

    22 Feb 1909 · 270 km away

  3. 1919M7.8

    Fiji Islands

    1 Jan 1919 · 98 km away

    tsunami

  4. 1950M7.7

    Tonga Islands

    14 Dec 1950 · 211 km away · intensity VI

  5. 1997M7.7

    Tonga Islands

    14 Oct 1997 · 242 km away

    tsunami

  6. 1994M7.6

    Fiji Islands

    9 Mar 1994 · 245 km away

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

Nearby trackers

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