M4.0 earthquake 2km WSW of Delta, B.C., MX

A magnitude 4.0 earthquake struck 2km WSW of Delta, B.C., MX on Thu, May 31, 1984, 4:30 PM PDT (23:30 UTC), 6 km (4 mi) below the surface.

A larger quake followed: M4.1 67km WSW of Alberto Oviedo Mota, B.C., MX. 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
4.05	ML, local (Richter)	Southern California Seismic Network	Preferred · Final · 10 stations
4.1	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed

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: 85 in the 60 days after this one and 88 in the 30 days before it.

The first 60 of 85.

From the USGS Earthquake Hazards Program and its partner networks, event ci41252 (also filed as usp00024se). Read Thu, Oct 1, 2026, 2:48 PM UTC.