M1.8 Earthquake near Petrolia, CA — 01 August 2026
A micro earthquake of magnitude 1.8 was recorded near Petrolia, CA on , with an epicentre 17 km southeast of Petrolia, at a focal depth of 14.4 km.
Time (UTC): 2026-08-01 19:59:40
Time (your timezone): —
Magnitude: 1.8 (micro)
Focal depth: 14.4 km (shallow)
Epicentre: 40.2142, -124.1420
Location: 17 km SE of Petrolia, CA
USGS link to NOAA tsunami information: Not linked
Review status: Automatic
Source: USGS event page
How strong was this earthquake?
Micro earthquakes are almost never felt at the surface and are recorded only by seismographs.
A magnitude 1.8 earthquake radiates roughly 7.6 kg of TNT equivalent in seismic energy.
The USGS assigns this earthquake a significance score of 50, which is below the USGS threshold of more than 600 for its significant-earthquake list. The ranking combines magnitude with available Did You Feel It responses and PAGER alert level; it is not a direct measurement of damage.
Where was the epicentre?
The epicentre was located at 40.2142, -124.1420 — 17 km southeast of Petrolia. The closest other recorded event was a magnitude 0.7 earthquake 189 km southeast of here on 01 August 2026.
Why the 14 km depth matters
At 14 km this was a shallow earthquake. Shallow events release their energy close to the surface, so for a given magnitude they produce noticeably stronger shaking — and more damage — than deeper ones. Roughly three quarters of all earthquakes worldwide occur at shallow depths.
This catalogue does not ingest eyewitness responses, so it cannot confirm where this earthquake was felt. Based on magnitude alone, events this small are usually detected by instruments rather than people. Its shallow focus makes stronger surface shaking more likely than for a deeper event of the same magnitude.
What does the tsunami information flag mean?
The USGS record does not carry a link to NOAA tsunami information. That field is not an all-clear and does not state whether a tsunami occurred. In this case, a damaging tsunami would be less likely because at M1.8 it falls below the magnitude 6.5 threshold that generally applies before a submarine earthquake displaces enough water to generate a damaging tsunami; it occurred inland rather than beneath the sea floor. For an active coastal alert, use tsunami.gov or your local warning authority.
How earthquakes generate tsunamis, and what the alert levels mean →
Aftershocks and local seismic history
No further earthquakes have been recorded within about 150 km of the epicentre since this event was recorded.
37 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.7 event near Pistol River on 03 June 2026. This M1.8 event released about 707,946 times less energy than that event.
How long aftershock sequences last, and how large they get →
Where this event sits in the record
This earthquake is part of the August 2026 worldwide record. Browse the full monthly archive to compare periods.
Nearest recorded earthquakes to this epicentre
- M0.7 earthquake near Cobb, CA — (189 km SE)
- M0.6 earthquake near The Geysers, CA — (190 km SE)
- M0.8 earthquake near Cloverdale, CA — (190 km SSE)
- M1.3 earthquake near Cloverdale, CA — (190 km SSE)
- M1.2 earthquake near Cloverdale, CA — (190 km SSE)
- M1.1 earthquake near Cloverdale, CA — (190 km SSE)
- M1.4 earthquake near Cloverdale, CA — (190 km SSE)
- M0.9 earthquake near Cloverdale, CA — (190 km SSE)
- M1.1 earthquake near Cloverdale, CA — (190 km SSE)
- M1.0 earthquake near Cloverdale, CA — (190 km SSE)
Other magnitude 1 earthquakes worldwide
- M1.9 earthquake near Ugashik, Alaska —
- M1.6 earthquake near Whites City, New Mexico —
- M1.6 earthquake near Albany, CA —
- M2.1 earthquake near Pāhala, Hawaii —
- M1.7 earthquake near Aleneva, Alaska —
- M1.7 earthquake near Toyah, Texas —
- M1.6 earthquake near Toyah, Texas —
- M1.7 earthquake near Silver Springs, Nevada —
Questions about this earthquake
How strong is a magnitude 1.8 earthquake?
Micro earthquakes are almost never felt at the surface and are recorded only by seismographs. A magnitude 1.8 earthquake radiates roughly 7.6 kg of TNT equivalent in seismic energy.
How deep was the earthquake near Petrolia?
At 14 km this was a shallow earthquake. Shallow events release their energy close to the surface, so for a given magnitude they produce noticeably stronger shaking — and more damage — than deeper ones. Roughly three quarters of all earthquakes worldwide occur at shallow depths.
Was the M1.8 earthquake near Petrolia felt?
This catalogue does not ingest eyewitness responses, so it cannot confirm where this earthquake was felt. Based on magnitude alone, events this small are usually detected by instruments rather than people. Its shallow focus makes stronger surface shaking more likely than for a deeper event of the same magnitude.
What does the USGS tsunami field mean for this event?
The USGS record does not carry a link to NOAA tsunami information. That field is not an all-clear and does not state whether a tsunami occurred. In this case, a damaging tsunami would be less likely because at M1.8 it falls below the magnitude 6.5 threshold that generally applies before a submarine earthquake displaces enough water to generate a damaging tsunami; it occurred inland rather than beneath the sea floor. For an active coastal alert, use tsunami.gov or your local warning authority.
Have there been aftershocks?
No further earthquakes have been recorded within about 150 km of the epicentre since this event was recorded.
How often do earthquakes happen near Petrolia?
37 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.7 event near Pistol River on 03 June 2026. This M1.8 event released about 707,946 times less energy than that event.