Introduction to the earthquake
Location uncertainty:4.022°S 152.489°E ±8.7 km
Depthuncertainty:10.0 km ±1.7
Origin Time:2017-05-15 13:22:38.580 UTC
FE Region:NEW BRITAIN REGION, PAPUA NEW GUINEA (192)
The depth where the earthquake begins to rupture.
This depth may be relative to the WGS84 geoid, mean
sea-level, or the average elevation of the seismic
stations which provided arrival-time data for the
earthquake location. The choice of reference depth
is dependent on the method used to locate the earthquake,
which varies by seismic network. Since ComCat includes
data from many different seismic networks, the process
for determining the depth is different for different
events. The depth is the least-constrained parameter
in the earthquake location, and the error bars are generally
larger than the variation due to different depth determination methods.
Sometimes when depth is poorly constrained by available seismic
data, the location program will set the depth at a fixed value.
For example, 33 km is often used as a default depth for earthquakes
determined to be shallow, but whose depth is not satisfactorily
determined by the data, whereas default depths of 5 or 10 km are
often used in mid-continental areas and on mid-ocean ridges since
earthquakes in these areas are usually shallower than 33 km.
An earthquake begins to rupture at a hypocenter which is defined by a
position on the surface of the earth (epicenter) and a depth below this
point (focal depth). We provide the coordinates of the epicenter in units
of latitude and longitude. The latitude is the number of degrees north (N)
or south (S) of the equator and varies from 0 at the equator to 90 at the poles.
The longitude is the number of degrees east (E) or west (W) of the prime meridian
which runs through Greenwich, England. The longitude varies from 0 at Greenwich to
180 and the E or W shows the direction from Greenwich.