II. Earthquakes Small magnitude earthquakes are much more common than larger magnitude earthquakes

II. Earthquakes Deaths from earthquakes vary from year to year depending on where they occur with respect to population centers and with varying degrees of earthquake preparedness (say differences in building design).

Deaths from earthquakes vary from year to year depending on where they occur with respect to population centers and with varying degrees of earthquake preparedness (say differences in building design). Global population Source: USDA - NRCS

Deaths from earthquakes vary from year to year depending on where they occur with respect to population centers and with varying degrees of earthquake preparedness (say differences in building design). Earthquakes

II. Earthquakes *Haiti (2010) – 7.0 M Tangshan, China (1976) – 7.8 M Yellow highlights similar magnitude earthquakes II. Earthquakes *Haiti (2010) – 7.0 M 222,570 people killed, 300,000 injured, 1.3 million displaced, 97,294 houses destroyed and 188,383 damaged Tangshan, China (1976) – 7.8 M 242,000 killed *Armenia (1988) – 6.9 M w/ 5.9 M aftershock (4 minutes later) 25,000 killed Mexico City (1985) – 8.1 M 8000 killed *San Francisco (1989) – 7.1 M (Loma Prieta earthquake) 62 killed *L.A. area (1994) – 6.8 M (Northridge earthquake) 51 killed Kobe, Japan (1995) – 6.9 M 6300 killed *we will be using these events to contrast earthquakes in urban areas in more developed and richer societies that were prepared versus less developed countries where societies were not prepared.

II. Earthquakes Armenia (1988) – 6.9 M w/ 5.9 M aftershock 25,000 killed; 31,000 more injured, 500,000 homeless (~71%) Major damage to 84 hospitals Killed or injured ~80% of doctors/nurses Major cause of death and injuries >>> Building collapse Prefab concrete buildings pancaked Economic losses < <$1 billion Tectonic setting: Continent-Continent collision

II. Earthquakes Mexico City – 8.1 M (19 Sept 1985) Focus/epicenter 350 km (220 miles) west of city at subduction zone margin Two major aftershocks: 7.5 M (21 Sept) & 7.1 M (25 Oct) 8000+ deaths, mostly due to building collapse Earthquake caused little damage/deaths in cities and villages between epicenter and Mexico City Why? Enhanced shaking (seismic wave amplification) Eight story building

II. Earthquakes Loma Prieta (1989) – 7.1 M (World Series earthquake) 42 km (26 mile) section of San Andreas fault ruptured 67 killed; 3757 injured; 12,000 homeless Majority of deaths due to collapse of Nimitz Freeway bridge Buildings in Marina district partially collapsed $6 billion in property damage

II. Earthquakes Kobe, Japan (1995) – 6.9 M 50 km section of fault ruptured, 1.7 meters horizontal and 1 meter vertical ~6400 killed (small % of 1.5 million residents) 150,000 buildings damaged/destroyed; many traditional wooden structure homes w/ heavy tile roofs Economic losses ~ $2.9 billion

II. Earthquakes Anchorage, Alaska – 9.2 M Good Friday, 1964 131 killed Major killer was tsunami (122 of 131) Major liquefaction in the Turnagain subdivision Major losses in the shipping and fishing industries Tsunami damage Liquefaction damage