Earthquake Destruction

Where Do Earthquakes Occur and How Often? ~ 80% of all earthquakes occur in the circum- Pacific belt –most of these result from convergent boundary activity –~15% occur in the Mediterranean- Asiatic belt –remaining 5% occur in the interiors of plates and on spreading ridge centers –more than 150,000 quakes strong enough to be felt are recorded each year

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.

Richter Scale How many times stronger is an earthquake that measures 5 on the Richter Scale than an earthquake that measures a 2? 1000 times stronger times10 times10 = 1000

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!!

Elevated Highways: A Common Problem Too much weight on concrete columns!

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 11th Watch Video Another Video of Japan - BBC link

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

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

Stop Disasters and Save a Town! visit this website and play the game. When you complete the activity, write a paragraph summary of what you did to save the town and why or why not it was successful. Be sure to include your results

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

Earthquake Facts The largest recorded earthquake in the United States was a magnitude 9.2 that struck Prince William Sound, Alaska on Good Friday, March 28, 1964 UTC. The largest recorded earthquake in the world was a magnitude 9.5 (Mw) in Chile on May 22, The earliest reported earthquake in California was felt in 1769 by the exploring expedition of Gaspar de Portola while the group was camping about 48 kilometers (30 miles) southeast of Los Angeles.

Earthquake Facts The average rate of motion across the San Andreas Fault Zone during the past 3 million years is 56 mm/yr (2 in/yr). This is about the same rate at which your fingernails grow. Assuming this rate continues, scientists project that Los Angeles and San Francisco will be adjacent to one another in approximately 15 million years. The East African Rift System is a km (31-37 miles) wide zone of active volcanic and faulting that extends north-south in eastern Africa for more than 3000 km (1864 miles) from Ethiopia in the north to Zambezi in the south. It is a rare example of an active continental rift zone, where a continental plate is attempting to split into two plates which are moving away from one another.

Earthquake Facts It is thought that more damage was done by the resulting fire after the 1906 San Francisco earthquake than by the earthquake itself. From there were only four states that did not have any earthquakes. They were: Florida, Iowa, North Dakota, and Wisconsin. The swimming pool at the University of Arizona in Tucson lost water from sloshing (seiche) caused by the 1985 M8.1 Michoacan, Mexico earthquake 2000 km (1240 miles) away.

Earthquake Facts The world’s deadliest recorded earthquake occurred in 1556 in central China. It struck a region where most people lived in caves carved from soft rock. These dwellings collapsed during the earthquake, killing an estimated 830,000 people. In 1976 another deadly earthquake struck in Tangshan, China, where more than 250,000 people were killed. The San Andreas fault is NOT a single, continuous fault, but rather is actually a fault zone made up of many segments. Movement may occur along any of the many fault segments along the zone at any time. The San Andreas fault system is more that 1300 km (800 miles) long, and in some spots is as much as 16 km (10 miles) deep.

Historical Quakes YearPlaceDeathsMagnitudeOther 1886 Charleston, SC 60 Greatest quake in Eastern US 1906 San Francisco Major damage 1923 Tokyo, Japan 143, Total destruction 1960 Southern Chile Largest quake recorded 1964Alaska Largest North American quake 1971 San Fernando, CA Damage over $1 Billion 1989 Loma Prieta, CA Over $6 Billion in damage 1994 Northridge, CA Over $40Billion in damage 2001 Bhuj, India 20, Left 1 million homeless

Earthquakes Japanese Earthquake