M2.8 · 7 km NW of The Geysers, CA

2026-08-11 21:35:14 UTC · 44.7 km (NNW) · depth 2.5 km

magnitude

2.8

distance

44.7 km

depth

2.5 km

envelope peak

47 µV

envelope SNR

4×

P predicted

7.7 s

sustain

11.6 s

low/high band

12.6×

vs NP.1835

1.00×

Listen for how the pitch balance changes at the P wave (marked where it was picked), at the S wave (the dashed mark is its predicted arrival) and through the coda that follows. Volume is normalised to this clip, so it only says how much energy there is before, during and after the event relative to its own peak — not how big the earthquake was.

• Peak 159 µV. The workhorse event: its waveform was scaled and superposed onto recorded cultural noise to measure how much sensitivity the station loses while someone is dragging trash cans past it (about two thirds of a magnitude unit, as it turns out).
• Compared against the strong-motion station 1.6 km away, it says this geophone reads about 3× quieter than its nameplate — the calibration now in use.

Side by side with USGS NP.1835, 1.64 km away, both in ground velocity.

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