Sanlien P-Alert Manual De Usuario página 44

Sensors 2008 , 8
The standard deviation of the estimate of M
τ for each event with at least four measurements.
the average
c
Figure 3 shows the relationship between Pd and PGV for the 780 records with epicentral distances
less than 30 km from Japan, Taiwan and southern California. We obtained a regression relation
log(PGV) = 0.920 log(Pd) + 1.642 ± 0.326 (PGV in cm/sec and Pd in cm)
Taiwan 507 records
Southern California 199 records
100
Japan 74 records
10
1
0.1
0.001
Figure 3. Relationship between peak initial three-second displacement amplitude (Pd) and peak
ground velocity (PGV) for 780 records with the epicentral distances less than 30 km for Japan (black
triangles), southern California (red solid circles) and Taiwan (blue diamonds). Solid line indicates the
least squares fit and the two dashed lines show the range of one standard deviation.
Instrumental intensity scale for large events is defined with respect to PGV (Wald et al., 1999a,
1999b; Wu et al., 2003). Using these relationships, the shaking intensity can be estimated from a single
station with a standard deviation of 1.0 unit of MMI scale or 0.6 unit of Japan and Taiwan intensity
is 0.41 for all the events. This regression is based on
w
Linear regression over 780 records
log(PGV)=0.920 log(Pd) + 1.642
SDV = 0.326
0.01 0.1
Pd (cm)
1 10
6
(5)