What kind of damage does ground shaking cause?
Ground shaking causes 99% of the earthequake damage to California homes. • Q: What system does the USGS use to characterize the severity of ground shaking at different location? A: The USGS uses a scale based on ground acceleration (as a percentage of the acceleration due to the force of gravity) and the Modified Mercalli Intensity Scale (Mercalli Scale). The 12-level intensity scale represents the effects of the shaking on people, manmade structures, and on the landscape by a number. Seismologists use the list to represent the severity of ground shaking in a community or part of a community by a number. List of 1-12 levels of the Modified Mercalli Intensity Scale of 1931 (Abridged; Wood and Neumann, 1931)? See Earthquakes & Volcanoes, v. 25, no. 2, 1994, p. 87 for further details. • Q: What is an isoseismal map? A: A map showing intensities at individual locations may be contoured with isoseismal lines, to provide a representation of the broad variations of the shaking over the region
