Earthquakes in the U.S.By: Allison Kantner and Nikki

Ryan

Prince William Sound, Alaska

• March 28, 1964• Magnitude: 9.2:• Second largest ever• Lasted four minutes• Aftershock zone was about 250 km wide and

extended 800 km• Thousands of aftershocks were recorded• Caused by the compression of the crust by the

nw motion of the Pacific Plate

Andreanof Islands, AlaskaAndreanof Islands, Alaska

March 9, 1957March 9, 1957– Magnitude 9.1Magnitude 9.1– Third largest earthquake in Third largest earthquake in

the 20the 20thth Century Century– Destroyed two bridges, Destroyed two bridges,

damaged houses, and left a damaged houses, and left a 4.5 meter crack in the road.4.5 meter crack in the road.

– Mount Vsevidof erupted Mount Vsevidof erupted after being dormant for 200 after being dormant for 200 years.years.

– Shock generated a 15 Shock generated a 15 meter tsunami that meter tsunami that continued to Hawaii.continued to Hawaii.

Gulf of Alaska

• Damage consisted of broken glassware and cracks in plaster, drywall, windows, and foundation

• Magnitude 7.9• Depth is 65 km• Light damage occurred• in other towns• Strong building vibrations • made it difficult to stand or walk

Denali Fault, AlaskaDenali Fault, Alaska• November 3, 2002

•Magnitude 7.9•Largest inland earthquake in North America in almost 150 years•Total rupture length: about 330 km•Rupture lasted 100 seconds from its initiation to its arrest•Multiple land slides and rock avalanches resulted•Earthquake was felt in Washington and caused seiches in pools and lakes as far as Texas and Louisiana

Gorda Plate

• November 8, 1980• Magnitude: 7.4• Caused minimal

damage considering the magnitude

• Center of the shock located offshore

Kern County, CaliforniaKern County, California July 21, 1952July 21, 1952

– Magnitude 7.3Magnitude 7.3– 12 deaths12 deaths– Caused property damage worth Caused property damage worth

$60 million$60 million– Cracked reinforced-concrete Cracked reinforced-concrete

tunnels with 46 cm thick wallstunnels with 46 cm thick walls– Bear Mountain moved upward Bear Mountain moved upward

and to the northand to the north– A building in Las Vegas required A building in Las Vegas required

realignment of the structural realignment of the structural steelsteel

– Felt over most of California and Felt over most of California and in the western parts of Arizona in the western parts of Arizona and Nevadaand Nevada

Hebgen Lake, Montana

• August 18, 1959• Magnitude: 7.3• Caused 28 fatalities,$11 million dollars

damage to highways and forests• Most disastrous effect: huge avalanche

cascading down the Madison river Canyon• This stopped the flow of the Madison river

and within weeks created a lake 53 m deep

Landers, CaliforniaLanders, CaliforniaJune 28, 1992June 28, 1992– Magnitude 7.3Magnitude 7.3– More than 400 people were injuredMore than 400 people were injured– Preliminary estimate of damage Preliminary estimate of damage

(combined with a 6.7 event earlier (combined with a 6.7 event earlier that day): $92 millionthat day): $92 million

– Felt throughout southern California, Felt throughout southern California, southern Nevada, western Arizona, southern Nevada, western Arizona, and southern Utahand southern Utah

– Felt in high-rise buildings as far north Felt in high-rise buildings as far north as Boise, Idaho, and as far east as as Boise, Idaho, and as far east as Albuquerque, New Mexico, and Albuquerque, New Mexico, and Denver.Denver.

– Seiches reported in Lake Union, Seiches reported in Lake Union, Washington, Aurora, Colorado, and Washington, Aurora, Colorado, and Corpus Christi, TexasCorpus Christi, Texas

Kalapana, Hawaii

• Nov. 29, 1975• Magnitude: 7.2• Killed 2 people and injured several• Inflicted property damage at $4.1 million• Hundreds of aftershocks felt• Felt throughout Hawaii Island and on

Lanai, Molokai, and Oahu. • Caused a brief, sudden volcanic eruption

Borah Peak, IdahoBorah Peak, Idaho• October 28, 1983

– Magnitude 7.0– Largest earthquake recorded in Idaho– 2 deaths– $12.5 million in property damage– Ground breakage was as wide as 100

meters– Rockfalls and landslides on the Lost

River Range– Felt in parts of Montana, Nevada,

Oregon, Utah, Washington, Wyoming, and in the Provinces of Alberta, British Columbia, and Saskatchewan, Canada

Dixie Valley, Nevada

• December 16, 1954• Magnitude: 7.1• Minor geologic effects included changes in the

flow of springs and wells, formation of craters and water fountains, landslips and landslides, mudflows, and rock falls.

• The earthquake was accompanied by offsets along many faults in the four main zones of a north-trending belt 96 kilometers long by 32 kilometers wide.

What Causes Earthquakes?What Causes Earthquakes?

Rock underground suddenly breaks along Rock underground suddenly breaks along a faulta fault

This causes seismic waves This causes seismic waves The two blocks of rock, or faults, push The two blocks of rock, or faults, push

against each otheragainst each otherDue to all of the pressure, the rocks break. Due to all of the pressure, the rocks break.

This causes the earthquake to occur. This causes the earthquake to occur.

Earthquake FactsEarthquake Facts

There are 19 major (magnitude larger than 7) There are 19 major (magnitude larger than 7) earthquakes every yearearthquakes every year

Earthquakes tend to be concentrated in narrow Earthquakes tend to be concentrated in narrow zoneszones

There are 7 major crustal plates on earth that There are 7 major crustal plates on earth that move from less than .5 to 5 inches per yearmove from less than .5 to 5 inches per year

There are several million earthquakes in the There are several million earthquakes in the world each yearworld each year

The largest earthquake recorded took place in The largest earthquake recorded took place in Chile in 1960. It had a magnitude of 9.5Chile in 1960. It had a magnitude of 9.5

QuestionsQuestions

How far did the tsunami that was How far did the tsunami that was generated by the Andreanof Island generated by the Andreanof Island earthquake of 1957 continue?earthquake of 1957 continue?

Which earthquake was the largest inland Which earthquake was the largest inland earthquake in almost 150 years?earthquake in almost 150 years?

How many major earthquakes are there How many major earthquakes are there every year?every year?

What causes earthquakes?What causes earthquakes? How many major crustal plates are there How many major crustal plates are there

on earth?on earth?

Bibliography http://neic.usgs.gov/neis/eq_depot/usa/1957_03_09.html http://www.dot.state.ak.us/comm/denali_quake/pages/

IMG_0128.htm : Denali Fault, Alaska http://www.giseis.alaska.edu/Seis/M7.9_quake_2002/M7.9_q

uake.html http://neic.usgs.gov/neis/eq_depot/usa/1952_07_21.html http://neic.usgs.gov/neis/eq_depot/usa/1992_06_28.html http://wwwneic.cr.usgs.gov/neis/eq_depot/usa/

1983_10_28.html