Magnitude4.9

Reviewed by USGSJapan34y ago

M4.9 earthquake 16 km W of Kushiro, Japan

Thursday, February 4, 1993, 14:43:12 UTC · 42.964°N, 144.179°E

A magnitude 4.9 earthquake struck 16 km W of Kushiro, Japan on Thursday, February 4, 1993, 14:43:12 UTC, at a depth of 99.4 km (intermediate). It is the strongest earthquake within 300 km since an M7.6 on January 15, 1993.

Magnitude
4.9
Light · mb
Depth
99 km
Intermediate
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

338 tons of TNT

That is about 1/45 of the Hiroshima bomb. A magnitude 5.0 releases about 1 times more energy.

Tectonic setting

180 km

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

Depth: intermediate

99 km

Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.

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 M4.5 on February 5, 1993. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M51h6h1d3d7d14d30dMainshock M4.9
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 4.532 km WSW of Kushiro, Japan34y ago · 18 km SW of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 882 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 46 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 297 recorded deaths. The most severe:

  1. 1982M6.7

    Hokkaido, Urakawa, Hiroo

    21 Mar 1982 · 174 km away · intensity X

    110 deaths$1 million damagetsunami

  2. 1968M8.2

    Off East Coast Of Honshu Island

    16 May 1968 · 254 km away · intensity VI

    52 deaths$131 million damagetsunami

  3. 1843M8.4

    Hokkaido: Yezo, Kushiro, Nemuro

    25 Apr 1843 · 184 km away

    45 deathsModerate damage ($1–5M)tsunami

  4. 1952M8.1

    Hokkaido

    4 Mar 1952 · 94 km away · intensity IX

    33 deathsSevere damage ($5–24M)tsunami

  5. 1973M7.7

    Hokkaido Island

    17 Jun 1973 · 134 km away · intensity VIII

    27 deaths$5 million damagetsunami

  6. 1856M8.0

    Oshima

    23 Aug 1856 · 280 km away · intensity V

    26 deathsModerate damage ($1–5M)tsunami

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

Nearby trackers

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