Source Parameter Search

Focal Mechanism Icon Output Formats

Hypocenter information with the hypocenter source, SRC, is given in each listing.
Coordinated Universal Time (UTC) is used throughout.
Depths are given in kilometers.

Mw is computed from the scalar moment of the moment tensor using the Hanks and Kanamori (1979) formula:
Mw = (2/3) log Mo - 10.7

where Mo is the scalar moment of the best double couple in dyne-cm (1 Newton-meter = 107 dyne-cm). Mo, computed from low frequency seismic data, is a measure of the displacement and area ruptured by an earthquake.

Me is computed from the radiated energy using the Choy and Boatwright (1995) formula:
Me = (2/3) log Es - 2.9

where Es is the radiated seismic energy in Newton-meters. Me, computed from high frequency seismic data, is a measure of the seismic potential for damage.

FM Format

The FM listing shows scalar moments, depths, fault plane solutions, and principal axes, and nodal planes.

EX is the exponent to the base ten of the scale factor, in Newton-meters, by which the scalar seismic moment and/or eignevalues identified with the principal axes are to be multiplied.
Sample FM Listing

MM Format

The MM listing shows moments, depths, and the NEIC radiated energy.

EX is the exponent to the base ten of the moment and radiated energy, in Newton-meters. ERR is the standard deviation of the radiated energy.
Sample MM Listing

MT Format

The MT listing shows moments, depths, and moment tensor components.

EX is the exponent to the base ten of the moment, in Newton-meters.
Sample MT Listing