Earthquake.now

M1.8 Earthquake near Almanor, United States — 04 September 2026

A micro earthquake of magnitude 1.8 was recorded near Almanor, United States on , with an epicentre 4 km northeast of Almanor, at a focal depth of 11.4 km. It ranked as the 2137th strongest of 7936 earthquakes recorded in the United States in the preceding 30 days.

1.8 Micro

Time (UTC): 2026-09-04 09:01:34

Time (your timezone): —

Magnitude: 1.8 (micro)

Focal depth: 11.4 km (shallow)

Epicentre: 40.2448, -121.1460

Location: 4 km NE of Almanor, 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 1.8 earthquake radiates roughly 8.7 kg of TNT equivalent in seismic energy.

The USGS assigns this earthquake a significance score of 52, 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 00:56 local solar time at the epicentre, in the early hours of the morning.

This event was deeper than 74% of the 153,446 earthquakes recorded in the United States in our catalogue and stronger than 77% of them.

Where was the epicentre?

The epicentre was located at 40.2448, -121.1460 — 4 km northeast of Almanor. The closest other recorded event was a magnitude 2.3 earthquake 2 km west of here on 13 August 2026.

The nearest other settlements in our records are Almanor (18 km west-southwest), Anderson (87 km west), Alder Springs (152 km west-southwest) and Anderson Springs (222 km southwest).

Why the 11 km depth matters

At 11 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 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.

11 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.9 event near Dayton on 04 December 2025. This M1.8 event released about 1.2 million times less energy than that event.

177 earthquakes have been recorded within 100 km of this epicentre in the past year, 6 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 1 earthquakes worldwide

Questions about this earthquake

How strong was the earthquake near Almanor?

It measured magnitude 1.8 — a micro earthquake. A magnitude 1.8 earthquake radiates roughly 8.7 kg of TNT equivalent in seismic energy.

How deep was the earthquake near Almanor?

The focus was 11 km below the surface, which counts as shallow.

Was the Almanor earthquake felt at the surface?

At magnitude 1.8 and a focal depth of 11 km, shaking would have been concentrated near the epicentre.

When did the earthquake near Almanor happen?

04 September 2026 at 09:01 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 Almanor?

11 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.9 event near Dayton on 04 December 2025. This M1.8 event released about 1.2 million times less energy than that event.