Editing Earthquake (section)

===Shaking and ground rupture===
[[File:Haiti earthquake damage.jpg|thumb|Damaged buildings in [[Port-au-Prince]], [[2010 Haiti earthquake|Haiti]], January 2010]]

Shaking and [[surface rupture|ground rupture]] are the main effects created by earthquakes, principally resulting in more or less severe damage to buildings and other rigid structures. The severity of the local effects depends on the complex combination of the earthquake [[Richter magnitude scale|magnitude]], the distance from the [[epicenter]], and the local geological and geomorphological conditions, which may amplify or reduce [[wave propagation]].<ref>{{cite web |url=http://www.abag.ca.gov/bayarea/eqmaps/doc/contents.html |title=On Shaky Ground, Association of Bay Area Governments, San Francisco, reports 1995, 1998 (updated 2003) |publisher=Abag.ca.gov |access-date=2010-08-23 |url-status=dead |archive-url=https://web.archive.org/web/20090921082202/http://www.abag.ca.gov/bayarea/eqmaps/doc/contents.html |archive-date=2009-09-21 }}</ref> The ground-shaking is measured by [[ground acceleration]].

Specific local geological, geomorphological, and geostructural features can induce high levels of shaking on the ground surface even from low-intensity earthquakes. This effect is called site or local amplification. It is principally due to the transfer of the [[seismic]] motion from hard deep soils to soft superficial soils and the effects of seismic energy focalization owing to the typical geometrical setting of such deposits.

Ground rupture is a visible breaking and displacement of the Earth's surface along the trace of the fault, which may be of the order of several meters in the case of major earthquakes. Ground rupture is a major risk for large engineering structures such as [[dams]], bridges, and [[nuclear power stations]] and requires careful mapping of existing faults to identify any that are likely to break the ground surface within the life of the structure.<ref>{{cite web|url=http://www.consrv.ca.gov/cgs/information/publications/cgs_notes/note_49/Documents/note_49.pdf|title=Guidelines for evaluating the hazard of surface fault rupture, California Geological Survey|publisher=California Department of Conservation|year=2002|url-status=dead|archive-url=https://web.archive.org/web/20091009065422/http://www.consrv.ca.gov/cgs/information/publications/cgs_notes/note_49/Documents/note_49.pdf|archive-date=2009-10-09}}</ref>