QuakeFactsEvidence report · prepared 2 September 2026https://quakes99.com/entity/iscgemsup913451
USGS iscgemsup913451
21 Apr 1917, 04:52
182 km SSE of Hiroo, Japan
A magnitude 6.1 mw earthquake at 15 km depth.
Published location
Where is 182 km SSE of Hiroo, Japan?
This locator uses the coordinates in the approved source record. It shows geographic context, not a site boundary, safety zone or property-risk area.
40.826000, 144.301000
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What the numbers mean
Magnitude measures event size; depth locates the source below the surface. Neither value alone establishes local damage or personal risk.
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Use local emergency authorities and the live USGS event page. This historical evidence page is not an alert service.
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Catalog fields and provenance
Event ID
iscgemsup913451
Coordinates
40.826, 144.301
Network
iscgemsup
Significance
572