Chapter 4 Summary
Earthquakes result from sudden slippage along fault zones in response to accumulated stress. Most earthquakes occur at plate boundaries and are related to plate-tectonic processes. Earthquake hazards include ground rupture and shaking, liquefaction, landslides, tsunamis, coastal flooding, and fires. The severity of damage is determined not only by the size of an earthquake but also by underlying geology and the design of affected structures. While earthquakes cannot be stopped, their negative effects can be limited by (1) designing structures in active fault zones to be more resistant to earthquake damage; (2) identifying and, wherever possible, avoiding development in areas at particular risk from earthquake-related hazards; (3) increasing public awareness of and preparedness for earthquakes in threatened areas; (4) refining and expanding tsunami warning systems and public understanding of appropriate response; and (5) learning enough about patterns of seismicity over time along fault zones, and about earthquake precursor phenomena, to make accurate and timely predictions of earthquakes and thereby save lives. Until precise predictions on a short timescale become feasible, longer-term earthquake forecasts may serve to alert the public to general levels of risk and permit structural improvements and planning for earthquake response.
