Earthquakes and Ground Motions - Earthquake Engineering for Structural Design - page 224

d) Large earthquakes

6.6 - 7.9 M Major earthquake causing serious damage over

large areas in poorly constructed buildings.
Moderate damage to well-constructed buildings.

e) Great earthquakes

8 or greater Great earthquake causing serious damage in areas

several hundred kilometers across, also for
well-constructed buildings.

Another measure of earthquake size is the areaofthefault which slipped during
the earthquake. Small earthquakes result in small areas. Contrary, strong
earthquake occurs in large areas (Fig. 7.4). One can see that both corresponding
areas and seismic magnitude for interplate earthquakes are larger than for intraplate
earthquakes.

Magnitude

Interplate
earthquakes

Intraplate
earthquakes

Rupture area

Figure 7.4 Influence of rupture area