The seismologists who work with historical events gather macroseismic data from written records from cities that may not have been anywhere near the epicentral area.
A compilation of arrival times, sometimes millions of data, allows seismologists to have a clearer picture of the location and size of sub-surface structures.
Seismologists characterized it as a slow earthquake due to disproportionately large tsunami waves, rupture duration near 125 seconds, shallow near-trench slip, and deficiencies in energy.
