Earthquake Hazards I. Landslides - can be caused by earthquake hundreds of miles away Three main types: 1. Fall - usually from a cliff 2. Slip - i.e. slump 3. Flow - i.e. avalanche * Loess - wind blown sediment deposits

Earthquake Hazards I. Landslides landslide in La Conchita, California landslide in La Conchita, California

Earthquake Hazards II. Liquefaction * the fluidization of fairly solid ground Three main types: * 1. Flow - saturated sediments move horizontally (often toward lower elevations)

Earthquake Hazards II. Liquefaction *2. Fountaining - geyser of water and sand created by heavy layer of rock on saturated sand.

Earthquake Hazards II. Liquefaction *3. Flotation - saturated sand on the surface becomes liquefied. Objects could float or sink.

Earthquake Hazards II. Liquefaction - can cause major structural damage.

Earthquake Hazards II. Liquefaction - Susceptibility of SF Bay area to liquefaction

Earthquake Hazards III. Floods Four main types: * 1. Impoundment Flood - landslide blocks river’s flow, causing water to rise upstream. Non-lethal. Plenty of time to evacuate. Mostly property damage. Quake Lake

Earthquake Hazards III. Floods 2. Damburst Flood - contents of lake are released downstream due to damage to dam or levee Very lethal! May result after impoundment flood.

Earthquake Hazards III. Floods * 3. Displacement Flood - Water is forced out of a lake or river by a landslide or large-scale surface deformation.

Earthquake Hazards III. Floods * 4. Transgression Flood - Coastal land sinks during earthquake and ocean/lake/river water moves in. This type is permanent.

Earthquake Hazards IV. Great Waves * A. Tsunamis - extremely large waves that can travel across entire oceans and cause great destruction.

Earthquake Hazards IV. Great Waves A. Tsunamis - What causes a tsunami? - Violent shaking or surface deformation creates a shallow wave that covers a large area. - Ships at sea will not feel it. - May move up to a couple hundred miles per hour in open ocean. - As it nears land, the front edge of the wave slows down, but the back remains fast. Along with a shallow shore, this causes the wave to increase in height. - Sometimes, hundreds of feet high.

Earthquake Hazards IV. Great Waves A. Tsunamis

Earthquake Hazards IV. Great Waves A. Tsunamis - Are they very destructive?

Earthquake Hazards IV. Great Waves A. Tsunamis

Earthquake Hazards IV. Great Waves *B. Seiche - sloshing of water back and forth in a lake or enclosed harbor. - usually minimal damage / only reaches a few yards high.

Earthquake Hazards IV. Great Waves * C. Bore - single crest of water rushing along a river, often upstream. - can smash or overturn boats - example - Mississippi River,

Earthquake Hazards IV. Great Waves * D. Displacement Wave - great wave caused by displacement of water, due to landslide or underwater ground deformation. - example - Lituya Bay, Alaska - landslide pushed water 1720 ft. up opposite shore. - occurs in lakes or enclosed harbors.

Earthquake Hazards V. Structure Failure - even in recent years, 1000’s killed due to lack of building codes. - causes the most loss of life - China, Mexico, Armenia, and Turkey have all lost over 15,000 in single quakes in the past 25 years due to poorly built structures. - When looking at susceptibility to earthquakes, we need to consider three aspects:

Earthquake Hazards V. Structure Failure * A. Foundation - Structures built on solid rock stand up better than structures built on sand or loose sediment.

Earthquake Hazards V. Structure Failure * B. Materials - People build with what they have. Historically, it has been adobe, wood, or stone. - Wood has much more necessary flexibility. - Which is the most earthquake resistant? * Which is the least earthquake resistant? * Adobe - 100,000’s killed in China due to adobe building collapses. - Today, we use steel. It is extremely strong but will also bend slightly. Often used to reinforce concrete.

Earthquake Hazards V. Structure Failure * C. Design - Most buildings constructed to resist vertical forces, not horizontal forces. * 1. Resonance - If an earthquake shakes the ground at the same frequency of the building, the building itself will amplify the shaking and literally shake itself apart. - Two big problems? - Mexico City, % of all collapsed buildings in the downtown area were between 6 and 18 stories high. Very few of the shorter or taller buildings collapsed.

Earthquake Hazards V. Structure Failure C. Design - Structure failure in Mexico City, 1985.

Earthquake Hazards V. Structure Failure C. Design * 2. Outside ornaments or facade can fall off. - Two big problems?

Earthquake Hazards VI. Fire - Sometimes an earthquake can cause a fire so enormous that the earthquake itself is the lesser of the two evils. - Lisbon (1755), San Francisco (1906), Tokyo (1923). - How does an earthquake cause such disastrous fires? - historically, extensive use of wood in buildings and open flames for cooking. - broken gas lines and electrical lines - destruction of firefighting equipment and water lines - large number of separate fires that grow into one enormous fire - flammability of household items (couches, beds)

Earthquake Hazards VI. Fire

What is this and how did it kill 40,000 people?