Richter Scale A scale that measures the magnitude of the largest wave recorded on the seismogram.A scale that measures the magnitude of the largest wave recorded on the seismogram. The wave amplitude increases by 10 for every 1 magnitude increase on the scale.The wave amplitude increases by 10 for every 1 magnitude increase on the scale. A Magnitude 3 has waves 10 times bigger than a Magnitude 2.A Magnitude 3 has waves 10 times bigger than a Magnitude 2.

Earthquake Destruction Damage to buildings and other structuresDamage to buildings and other structures (bridges, roads) depends mainly on 3 things: (bridges, roads) depends mainly on 3 things: 1. Magnitude of earthquake waves and duration of earthquake 1. Magnitude of earthquake waves and duration of earthquake The stronger and longer the earthquake, the more damage it will do

Earthquake Destruction 2. Building & structure design – HOW was the building designed and constructed?2. Building & structure design – HOW was the building designed and constructed? –Steel-frame buildings CAN resist seismic waves –Unreinforced stone/brick buildings CANNOT!!

Earthquake Destruction 3. The type of ground that the buildings & structures are built on top of3. The type of ground that the buildings & structures are built on top of –Liquefaction – ground becomes saturated with water and turns like 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 & sewage lines underground can rise out of the ground and break.Gas, water & sewage lines underground can rise out of the ground and break.

Other Types of Damage Tsunami – 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/ Tsunami hit Sumatra because of the 3 rd most powerful Earthquake recorded since 1900.

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

Fire Fire starts when gas or electrical lines are broken during an earthquake ~harder to put out because water lines are often also broken during an earthquake

Landslides The sinking of ground triggered by earthquake vibrationsThe sinking of ground triggered by earthquake vibrations Can cause foundations of buildings or even ENTIRE buildings to collapseCan cause foundations of buildings or even ENTIRE buildings to collapse Can rupture gas, water or sewer linesCan rupture gas, water or sewer lines

Seismic Risk in U.S. Expected : California, Washington Unexpected : Florida, North Dakota, Minnesota Seismic Risk is developed by looking at the history of the area

Pictures of Damage

1906 – San Francisco

1906 – San Francisco

1906 – San Francisco – dead

Pakistan – October 2005

Pakistan – killed nearly 25,000 people

Sichuan Earthquake – 2008

Death Toll – Over 55,000