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After the 1971 San Fernando earthquake, geologists with California Division of Mines and
Geology conducted an intensive mapping effort in the San Fernando area to document the

surface effects and damage resulting from the event. Data were compiled in text and maps
presented in CDMG Bulletin No. 196 (Oakeshott, 1975) and document both primary and
secondary seismic hazards and damage in the areas affected by the 1971 earthquake.
Information presented in the report was used in evaluating potential seismic hazards at the

project property.

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The maximum credible earthquake (MCE)1 and maximum probable earthquake (MPE)2
as defined in CDMG Note #43 (1980), were estimated for the faults and fault zones
considered to have the greatest potential to generate earthquakes that could cause

significant strong ground motion at the project property (Table 7). MCE’s were estimated
using historical seisrnicity, empirical relationships between fault rupture length and
magnitude based on data from historical earthquakes (Slemmons, 1982; Bonilla and others,
1984; Slemmons and others, 1989; and Wells and Coppersmith, 1992) and published geologic
evidence of paleoseismic events. The fault rupture lengths used to estimate the MCEs are

the longest segments, based on geologic and/or seismic data, which are considered likely to
rupture in a single earthquake. The estimated MCE’s are believed to be reasonably
conservative and generally consistent with the magnitude estimates for these faults by Ziony
(1985) and Wesnousky (1986). MPE’s were estimated using fault dimensions, slip rates, and
regional seismic parameters applied to the method of Molnar (1979), as well as professional
judgement.

Estimated MCE’s and MPE’s are reported using moment magnitude (MW) scale. For the
purposes of this assessment, Mw is assumed to be equivalent to surface wave magnitude

‘ The CDMG (Note #43) definition of a maximum credible earthquake is the maximum earthquake that
appears capable of occurring under the presently known tectonic framework. It is a rational and believable event
that is in accord with all known geologic and seismologic facts. In determining the maximum credible
earthquake, little regard is given to its probability of occurrence, except that its likelihood of occurring is great
enough to be of concern.

2 The CDMG (Note #43) definition of a maximum probable earthquake is the maximum earthquake that
is likely to occur during a 100-year interval. It is to be regarded as a probable occurrence, not as an assured
event that will occur at a specific time.

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