Why Surface Monitoring of Microseismic Events Works

Passive energy recorded by ocean bottom seismic (OBS) sensors in 1000 m of water is analyzed using seismic interferometry. A low-frequency dispersive arrival is observed that is interpreted using the normal mode theory of water waves. The frequency of the passive energy is below the bandwidth of the airgun sources used in this survey allowing this analysis to take place during times of active shooting. The passive wave arrival times are useful for QC of the sensor timing and positions.