PHILIPPINE SEISMIC SOURCE TYPES

Having the Philippines situated in the the earthquake belt, most, if not all, parts of the country have experienced ground excitation one way or the other. The NSCP has stipulated three source descriptions of earthquakes from More than magnitude 7 to less than magnitude 6.5 which would most likely to occur in any region of the country. These values are used as they are the destructive range of magnitudes. It is left to the designer's prerogative on which to adopt.

In places where history does not reveal damaging seismic magnitudes, then the designer can opt to use the category showing less than magnitude 6.5. In most other places, designers keep the first line for factor of safety adopting the design for magnitudes more than 7.0.

SEISMIC SOURCE TYPE	SEISMIC SOURCE DESCRIPTION	MAXIMUM MOMENT MAGNITUDE, M
A	"Faults that are capable of producing large magnitude
	events and that have a high rate of seismic activity."	M is greater than or equal to 7.0
B	All faults other than Types A and C.	"M is greater than or equal to 6.5
		but less than 7.0"
C	"Faults that are not capable of producing large magnitude
	earthquakes and that have a relatively low rate of
	seismic activity."	M is less than 6.5

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