M3.2 · 6 km NW of The Geysers, CA

2026-08-12 10:28:21 UTC · 43.5 km (NNW) · depth 2.8 km

magnitude

3.2

distance

43.5 km

depth

2.8 km

envelope peak

64 µV

envelope SNR

18×

P predicted

7.5 s

sustain

12.6 s

low/high band

38.2×

vs NP.1835

0.89×

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 227 µV. The Geysers is the world’s largest geothermal field and produces several small earthquakes a day, driven by the wastewater injected to recharge the steam reservoir — some of it Santa Rosa’s own.
• That makes it a permanent calibration source 45 km away: same path every time, a new event every few days.

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

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