GEOS 1004 Lecture Notes - Lecture 10: Construction, Radon, San Andreas Fault
Document Summary
Damage (and thus hazard) depends on (#1): the distance from the earthquake. within a few km of fault. A m6 directly underfoot is worse than a m7 100 km away. Damage also depends on (#2): the local response of the ground shaking. Loose, wet sediment (basins) amplifies surface waves; bedrock is safer. e. g. anchorage, ak 1964, m9. 3. Liquefaction - water saturated sediment loses its strength when shaken, causing load above to shift and sink. In several ways: material, style of building, technology, engineering code, adherence to code (economy) Examples of moderate earthquakes that killed many; poor building construction (as well as location): Heavy stone or concrete shear walls and roofs that are unreinforced and un-bolted are bad; wood, metal skeletal structures that are reinforced are better. Also depends on building harmonics; whether seismic waves resonate depending on building"s natural frequency. Earthquakes in wealthy countries with good building codes see far fewer casualties, but much higher economic loss.
