Earthquakes are common on many active volcanoes.
They may result from movement of magma within the volcano or from tectonic processes associated with the volcano readjusting itself. A swarm occurs when a large number of earthquakes are recorded in a short period time on a volcano. Low level seismic activity has been documented on Loihi since 1959. In a typical month, between 2 and 10 Loihi earthquakes are detected on the Hawaii Volcano Observatory's seismic network. The number of Loihi earthquakes that have been recorded by the HVO network since 1959 are shown in the plot below.