M1.7 earthquake 6 km SSE of Copperopolis, California
A magnitude 1.7 earthquake struck 6 km SSE of Copperopolis, California on Fri, Oct 26, 1984, 12:20 PM PDT (19:20 UTC), 7 km (4 mi) below the surface.
A larger quake followed: M1.8 10 km ESE of Greeley Hill, California. This one was a foreshock.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 1.7 (md), micro
- Local time
- UTC
- 1984-10-26 19:20:29 UTC
- Depth
- 7.0 km (4.4 mi), shallow
- Epicenter
- 37.928° N, 120.605° 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 2.9 km horizontally, 1.0 km in depth
- Magnitude uncertainty
- ±0.07
- Depth from
- From location
- Station coverage gap
- 212°, poorly surrounded by stations
- Stations used
- 3
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 1.5 and up: 7 in the 60 days after this one and 6 in the 30 days before it.
After
- 1.69 km NE of Livermore, California · 15302 days ago · 12 km deep · 98 km away
- 1.810 km ESE of Greeley Hill, California · 15284 days ago · 15 km deep · 57 km away
- 2.76 km SSW of Mariposa, California · 15274 days ago · 17 km deep · 77 km away
- 2.416 km WSW of Diablo Grande, California · 15270 days ago · 3 km deep · 98 km away
- 1.81 km SSE of Mariposa, California · 15260 days ago · 5 km deep · 76 km away
- 1.610 km SSE of Yosemite Valley, California · 15259 days ago · 4 km deep · 100 km away
- 1.88 km ESE of Bethel Island, California · 15259 days ago · 5 km deep · 83 km away
Before
- 1.88 km SSE of Copperopolis, California · 15307 days ago · 4 km deep · 2 km away
- 2.15 km SE of Greeley Hill, California · 15308 days ago · 5 km deep · 52 km away
- 2.17 km SSW of Merced, California · 15319 days ago · 16 km deep · 77 km away
- 1.73 km E of Brentwood, California · 15328 days ago · 0 km deep · 92 km away
- 1.78 km E of Bear Valley, California · 15329 days ago · 4 km deep · 82 km away
- 2.07 km NE of Tracy, California · 15336 days ago · 13 km deep · 69 km away
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Sources
From the USGS Earthquake Hazards Program and its partner networks, event nc1121555. Read Tue, Sep 22, 2026, 10:26 PM UTC.