U.S. Geological Survey - Hawaiian Volcano Observatory
Earthquakes - Current EQ Map - Felt EQs - Destructive Eqs - Hazards,Zoning - Instrumentation
Vast amounts of seismic data provide a wealth of information on the active processes occurring within and beneath Hawai`i's volcanoes. Seismologists at HVO study the regional seismicity of the Island of Hawai`i, in particular the tectonic and volcanic earthquakes as they relate to major fault zones and to the eruptions and intrusions of magma. Volcanic earthquakes are directly associated with magma movement; earthquake swarms frequently precede eruptions or accompany intrusions. Commonly, earthquakes occur ahead of intruding magma, permitting us to anticipate the probable location of the outbreak of lava at the surface. On the other hand, tectonic earthquakes occur in fault zones or other regions away from the principal areas of magma movement.
Learning to identify the various types of seismic signatures recorded on our seismographs is the first basic step to understanding Hawaiian seismicity. Our seismographs record ground vibrations caused not only by natural phenomena but also by human and cultural activity. Different kinds of earthquakes will also have different seismic signatures.