Richter Scale• A scale that measures the A scale that measures the magnitudemagnitude of of

the the largest wavelargest wave recorded on the recorded on the seismogram.seismogram.

• The wave amplitude increases by The wave amplitude increases by 1010 for for every every 11 magnitude increase on the scale. magnitude increase on the scale.

• A Magnitude 3 has waves A Magnitude 3 has waves 10 times bigger10 times bigger than a Magnitude 2.than a Magnitude 2.

Earthquake Destruction• Damage to buildings and other structures Damage to buildings and other structures

(bridges, roads) depends mainly on 3 things:(bridges, roads) depends mainly on 3 things: 1. 1. MagnitudeMagnitude of earthquake of earthquake

waves and waves and durationduration of of earthquake earthquake

The The strongerstronger and and longerlonger the earthquake, the earthquake, the the more damagemore damage it will it will dodo

Earthquake Destruction• 2. 2. Building & structure design Building & structure design – HOW was – HOW was

the building designed and constructed?the building designed and constructed?– Steel-frame buildings Steel-frame buildings CANCAN resist seismic waves resist seismic waves– Unreinforced stone/brick buildings Unreinforced stone/brick buildings CANNOTCANNOT!!!!

Earthquake Destruction• 3. The 3. The type of groundtype of ground that the buildings & that the buildings &

structures are built on top ofstructures are built on top of– LiquefactionLiquefaction – ground becomes saturated with – ground becomes saturated with

water and turns water and turns like quicksandlike quicksand• Can’t support the structures that are on topCan’t support the structures that are on top• Buildings sink & collapseBuildings sink & collapse• Gas, water & sewageGas, water & sewage lines underground can rise out lines underground can rise out

of the ground and of the ground and breakbreak..

Other Types of DamageTsunami – seismic sea waves

~often called ‘Tidal Waves” but they are NOT caused by the tidal effects of the moon or sun

~caused by underwater earthquakes

As waves near the shore, the water slows down and piles up on itself – waves reach heights of 30 meters and can go as fast as 50km/hr

12/26/2004 - Tsunami hit Sumatra because of the3rd most powerful Earthquake recorded since 1900.

Japan’s Tsunami after the 4th Most Powerful Earthquake on Friday, March 11th, 2011

FireFire starts when Fire starts when gas or electricalgas or electrical lines are lines are broken during an earthquakebroken during an earthquake

~harder to put out because water lines are ~harder to put out because water lines are often also often also broken during an earthquakebroken during an earthquake

Landslides• The sinking of ground triggered by The sinking of ground triggered by

earthquake vibrationsearthquake vibrations

• Can cause foundations of buildings Can cause foundations of buildings or even or even ENTIREENTIRE buildings to buildings to collapsecollapse

• Can Can rupturerupture gas, water or sewer gas, water or sewer lineslines

Seismic Risk Seismic Risk in U.S.in U.S.Expected : Expected : California, WashingtonCalifornia, Washington

Unexpected : Unexpected : Florida, North Dakota, Florida, North Dakota, MinnesotaMinnesota

Seismic Seismic Risk is Risk is developed developed by looking by looking at the at the history of history of the areathe area

Pictures of Damage

1906 – San Francisco

1906 – San Francisco

1906 – San Francisco – 700- 3000 dead

Pakistan – October 2005

Pakistan – killed nearly 25,000 people

Sichuan Earthquake – 2008

Sichuan Earthquake – 2008Death Toll – Over 55,000