For oceanographers, this is more than a philosophical problem. Earthquakes and eruptions take place all of the time along the vast mid-ocean ridge system. However the chances that an oceanographer can be at the right place at the right time to witness an eruption or even find evidence of a recent eruption are remote. Now it is possible to hear seafloor eruptions without having to be there. Marine seismologist Maya Tolstoy and her colleagues are using underwater microphones called hydrophones to listen for earthquakes and eruptions and then pinpoint their locations.
All earthquakes produce a series of seismic waves that travel through the earth.
Seismologists traditionally locate and study earthquakes by measuring the magnitude and timing of these two types of waves. Maya and her colleagues, however, are taking advantage of third type of wave produced only by underwater earthquakes. The United States Navy originally deployed hydrophones to detect enemy submarines. After the cold war, the Navy gave scientists access to their hydrophones. About once a year, scientists and technicians journey out to these hydrophones to download the data and change the batteries.