Your smartphone has the same kind of sensor as a seismic accelerometer. Open this page on a phone, press Start, put the phone on a table and tap the table: you will see your own seismogram, in three components, just like at a CHARNET station.
LIVE · 10 s
Now0.0mg
Peak0.0mg
LevelQuiet
Press Start on a phone, or try the demo earthquake on a computer.
X, Y, ZTwo horizontal and one vertical component, the same three directions a seismometer records.
mgThousandths of the acceleration of gravity. Strong earthquakes shake the ground at hundreds of mg.
P and SIn the demo you will see the fast P wave first, then the stronger S wave, as in a real record.
Nothing is recorded or sent anywhere: the data stay on your phone. This is a teaching tool, not an earthquake detector.