XX.OAKMT.00.SHZ

DIY geophone seismometer · Oakmont, Santa Rosa, CA · vertical 4.5 Hz · independent station (not for scientific use)
Live · last 30 s (UTC)
connecting…
Live spectrum · same 30 s window · ASD µV/√Hz, log–log
Welch over the live 30 s ring (~0.12 Hz resolution). Updates as the ring does, ~every 3 s. The dashed line marks the geophone’s 4.5 Hz corner — response falls steeply below it, so the rise at the left is instrument, not ground.
Helicorder · last 4 hours (UTC)
helicorder

Each row is 15 minutes of ground motion, oldest at the top — read it like lines on a page. Height means how hard the ground moved, so an earthquake is a sudden fat burst that tapers away, while ordinary noise is an even fuzz.

The four colours carry no meaning. They cycle red, green, blue, black purely so your eye can follow one row without sliding into the next. This is a single sensor recording a single channel — not four feeds at once.

Faded stretches are things happening nearby — footsteps, a door, a car. They are identified by pitch: only something within a few metres arrives with energy above 15 Hz, because distance strips the high frequencies out of a real earthquake. The solid core drawn inside a faded burst is the 1–8 Hz part, the band a quake would occupy.

Coloured triangles mark where an earthquake from the USGS catalogue should have arrived — where to look, not a claim that this station caught it. Full guide to reading the drum →