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M0.4 Earthquake near Idyllwild, United States — 01 September 2026

A micro earthquake of magnitude 0.4 was recorded near Idyllwild, United States on , with an epicentre 9 km southwest of Idyllwild, at a focal depth of 13.0 km. It ranked as the 6992nd strongest of 7664 earthquakes recorded in the United States in the preceding 30 days.

0.4 Micro

Time (UTC): 2026-09-01 04:02:55

Time (your timezone): —

Magnitude: 0.4 (micro)

Focal depth: 13.0 km (shallow)

Epicentre: 33.6755, -116.7780

Location: 9 km SW of Idyllwild, CA

Country: United States

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 0.4 earthquake radiates roughly 0.06 kg of TNT equivalent in seismic energy.

The USGS assigns this earthquake a significance score of 3, 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.

What the magnitude scale actually measures →

When it happened locally

That is about 20:15 local solar time at the epicentre, in the evening.

This event was deeper than 77% of the 152,473 earthquakes recorded in the United States in our catalogue and stronger than 11% of them.

Where was the epicentre?

The epicentre was located at 33.6755, -116.7780 — 9 km southwest of Idyllwild. The closest other recorded event was a magnitude 0.1 earthquake 12 km south of here on 31 August 2026.

The nearest other settlements in our records are Aguanga (34 km south-southwest), Aliso Viejo (88 km west), Alpine (105 km south) and Adelanto (116 km northwest).

Why the 13 km depth matters

At 13 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.

Read more on how focal depth changes what you feel →

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 M0.4 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.

20 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 M0.4 event released about 234.4 million times less energy than that event.

10079 earthquakes have been recorded within 100 km of this epicentre in the past year, 911 of them in the past 30 days.

How long aftershock sequences last, and how large they get →

Where this event sits in the record

This earthquake is part of the September 2026 worldwide record, and of earthquakes in the United States during September 2026. Browse the full monthly archive to compare periods.

Nearest recorded earthquakes to this epicentre

Other recent earthquakes in the United States

All recorded earthquakes in the United States →

Other magnitude 0 earthquakes worldwide

Questions about this earthquake

How strong was the earthquake near Idyllwild?

It measured magnitude 0.4 — a micro earthquake. A magnitude 0.4 earthquake radiates roughly 0.06 kg of TNT equivalent in seismic energy.

How deep was the earthquake near Idyllwild?

The focus was 13 km below the surface, which counts as shallow.

Was the Idyllwild earthquake felt at the surface?

At magnitude 0.4 and a focal depth of 13 km, shaking would have been concentrated near the epicentre.

When did the earthquake near Idyllwild happen?

01 September 2026 at 04:02 UTC.

Was there a tsunami?

No. The USGS record carries no tsunami-information link for this event.

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 Idyllwild?

20 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 M0.4 event released about 234.4 million times less energy than that event.