Seismicity is quantitatively computed. Generally, the region under study is divided in equally sized areas defined by
latitude and
longitude, and the
Earth's interior is divided into various depth intervals on account of
Earth'slayering: Up to 50 km (31 mi) depth, 50–300 km (31–186 mi), and > 300 km (190 mi).[2]
The usual formula to calculate seismicity is:
where
: is the energy of a single seismic event (i.e., earthquake);