M1.8 earthquake 8 km SSE of Copperopolis, California
A magnitude 1.8 earthquake struck 8 km SSE of Copperopolis, California on Thu, Oct 25, 1984, 12:06 PM PDT (19:06 UTC), 4 km (3 mi) below the surface.
A larger quake followed: M2.7 6 km SSW of Mariposa, California. This one was a foreshock.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 1.8 (Md, duration), micro
- Magnitude from
- Northern California Seismic System
- Local time
- UTC
- 1984-10-25 19:06:02 UTC
- Depth
- 4.3 km (2.7 mi), shallow
- Epicenter
- 37.914° N, 120.589° W
- Region
- California
- Tsunami flag
- No
- Status
- Reviewed by a seismologist
Did you feel it?
No one has reported feeling this quake to the USGS.
How well it is located
Reviewed by a seismologist.
- Location uncertainty
- About 5.5 km horizontally, 5.0 km in depth
- Magnitude uncertainty
- ±0.19
- Depth from
- From location
- Station coverage gap
- 205°, poorly surrounded by stations
- Stations used
- 4
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 1.5 and up: 9 in the 60 days after this one and 5 in the 30 days before it.
After
- 1.76 km SSE of Copperopolis, California · 15316 days ago · 7 km deep · 2 km away
- 1.69 km NE of Livermore, California · 15312 days ago · 12 km deep · 99 km away
- 1.810 km ESE of Greeley Hill, California · 15293 days ago · 15 km deep · 55 km away
- 2.28 km WNW of Coarsegold, California · 15285 days ago · 5 km deep · 100 km away
- 2.76 km SSW of Mariposa, California · 15283 days ago · 17 km deep · 75 km away
- 2.416 km WSW of Diablo Grande, California · 15279 days ago · 3 km deep · 99 km away
- 1.81 km SSE of Mariposa, California · 15269 days ago · 5 km deep · 74 km away
- 1.610 km SSE of Yosemite Valley, California · 15269 days ago · 4 km deep · 98 km away
- 1.88 km ESE of Bethel Island, California · 15268 days ago · 5 km deep · 85 km away
Before
- 2.15 km SE of Greeley Hill, California · 15317 days ago · 5 km deep · 50 km away
- 2.17 km SSW of Merced, California · 15328 days ago · 16 km deep · 75 km away
- 1.73 km E of Brentwood, California · 15337 days ago · 0 km deep · 94 km away
- 1.78 km E of Bear Valley, California · 15339 days ago · 4 km deep · 82 km away
- 2.07 km NE of Tracy, California · 15345 days ago · 13 km deep · 70 km away
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Sources
From the USGS Earthquake Hazards Program and its partner networks, event nc1121528. Read Fri, Oct 2, 2026, 8:11 AM UTC.