M1.0 Earthquake near La Mesa, CA — 31 July 2026
A micro earthquake of magnitude 1.0 was recorded near La Mesa, CA on , with an epicentre 7 km north-northwest of La Mesa, at a focal depth of -0.3 km.
Time (UTC): 2026-07-31 20:13:38
Time (your timezone): —
Magnitude: 1.0 (micro)
Focal depth: -0.3 km (shallow)
Epicentre: 32.8203, -117.0630
Location: 7 km NNW of La Mesa, CA
USGS link to NOAA tsunami information: Not linked
Review status: Reviewed
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 1.0 earthquake radiates roughly 0.49 kg of TNT equivalent in seismic energy.
The USGS assigns this earthquake a significance score of 16, 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 32.8203, -117.0630 — 7 km north-northwest of La Mesa. The closest other recorded event was a magnitude 1.9 earthquake 16 km west of here on 01 August 2026.
Why the -0 km depth matters
At -0 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 M1.0 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
37 further earthquakes have been recorded within about 150 km of the epicentre in the 1 day since this event, the largest of them magnitude 3.3.
26 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 6.0 event near San Diego Country Estates on 14 April 2025. This M1.0 event released about 30.5 million 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 July 2026 worldwide record. Browse the full monthly archive to compare periods.
Nearest recorded earthquakes to this epicentre
- M1.9 earthquake near La Jolla, CA — (16 km W)
- M3.0 earthquake near Palomar Observatory, CA — (60 km N)
- M0.9 earthquake near Julian, CA — (63 km ENE)
- M0.8 earthquake near Pine Valley, CA — (74 km E)
- M0.7 earthquake near Anza, CA — (86 km NE)
- M0.8 earthquake near Borrego Springs, CA — (87 km NE)
- M0.6 earthquake near Anza, CA — (90 km NE)
- M0.8 earthquake near Anza, CA — (92 km NNE)
- M0.8 earthquake near Anza, CA — (92 km NE)
- M0.7 earthquake near Anza, CA — (92 km NNE)
Other magnitude 1 earthquakes worldwide
Questions about this earthquake
How strong is a magnitude 1.0 earthquake?
Micro earthquakes are almost never felt at the surface and are recorded only by seismographs. A magnitude 1.0 earthquake radiates roughly 0.49 kg of TNT equivalent in seismic energy.
How deep was the earthquake near La Mesa?
At -0 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 M1.0 earthquake near La Mesa 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 M1.0 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?
37 further earthquakes have been recorded within about 150 km of the epicentre in the 1 day since this event, the largest of them magnitude 3.3.
How often do earthquakes happen near La Mesa?
26 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 6.0 event near San Diego Country Estates on 14 April 2025. This M1.0 event released about 30.5 million times less energy than that event.