M3.9 earthquake 13 km S of Volcano, Hawaii

A magnitude 3.9 earthquake struck 13 km S of Volcano, Hawaii on Mon, Jul 20, 1981, 6:12 AM HST (16:12 UTC), 9 km (5 mi) below the surface.

A larger quake followed: M4.4 16 km ENE of P?hala, Hawaii. This one was a foreshock.

Map

Where this earthquake was located, with the others nearby. Select one for its page.

Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.

Mag.	Scale	Computed by	Notes
3.93	ML, local (Richter)	Hawaiian Volcano Observatory	Preferred · Final · ±0.21 · 2 stations
4.1	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed

The USGS’s account of the effects of this earthquake.

FELT ON HAWAII.

From the USGS event page for hv19812364. U.S. Geological Survey text and figures are in the public domain.

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

Distance and direction from each place to the epicenter, with its forecast.

Within 100 km, magnitude 1.5 and up: at least 201 in the 60 days after this one and 198 in the 30 days before it.

The first 60 of at least 201.

From the USGS Earthquake Hazards Program and its partner networks, event hv19812364 (also filed as usp0001eu1). Read Thu, Oct 1, 2026, 4:36 AM UTC.