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Colin  Braidy (redirected from Prince William Sound, Alaska)

Page history last edited by PBworks 16 years, 4 months ago




  Charles Richter



Earthquake causes sewer to collapse.  The biggest earthquake ever recored was in Deerfield, Kansas. An earthquake is the shaking of the ground caused by an abrupt shift of rock along a fracture in the Earth, called a fault. Within seconds, an earthquake releases stress that has slowly accumulated within the rock, sometimes over hundreds of years. Says CVO website (www.CVO.com) . Magnitude is a measure of the amount of energy released during an earthquake, and you've probably heard news reports about earthquake magnitudes measured using the Richter scale. The Richter scale was invented, logically enough, in the 1930s by Dr. Charles Richter, a seismologist at the California Institute of Technology.  Says New Mexico Bureau of geology and mineral Resources.



picture of charles richter and the first model of the richter scale. this is a picture of a earthquake in the ocean.this is a picture of 2006 JAC weekly DVOA performence.



Residents stand in front of their houses after heavy waves hit the neighborhood known as 'La Siberia', near the port city of Callao, Peru, on Thursday.

Death toll hits 450 in Peru earthquake


Earthquakes in B.C.


this shows the magnitude of earthquakes on the coast of colmbia and where earthquakes mostly occur.





This is a 24-hour long seismic record.
Time progress left to right and from top to bottom, just like text on a printed page.
Each line is 15 minutes long.
The hour marks are visible as a vertical stripe parallel to the left edge of the record.









Prince William Sound, Alaska


This great earthquake and ensuing tsunami took 128 lives (tsunami 113, earthquake 15), and caused about $311 million in property loss. Earthquake effects were heavy in many towns, including Anchorage, Chitina, Glennallen, Homer, Hope, Kasilof, Kenai, Kodiak, Moose Pass, Portage, Seldovia, Seward, Sterling, Valdez, Wasilla, and Whittier.



Anchorage, about 120 kilometers northwest of the epicenter, sustained the most severe damage to property. About 30 blocks of dwellings and commercial buildings were damaged or destroyed in the downtown area. The J.C. Penny Company building was damaged beyond repair; the Four Seasons apartment building, a new six-story structure, collapsed; and many other multistory buildings were damaged heavily. The schools in Anchorage were almost devastated. The Government Hill Grade School, sitting astride a huge landslide, was almost a total loss. Anchorage High School and Denali Grade School were damaged severely. Duration of the shock was estimated at 3 minutes.















The earthquake was accompanied by vertical displacement over an area of about 520,000 square kilometers. The major area of uplift trended northeast from southern Kodiak Island to Price William Sound and trended east-west to the east of the sound. Vertical displacements ranged from about 11.5 meters of uplift to 2.3 meters of subsidence relative to sea level. Off the southwest end of Montague Island, there was absolute vertical displacement of about 13 - 15 meters. Uplift also occurred along the extreme southeast coast of Kodiak Island, Sitkalidak Island, and over part or all of Sitkinak Island. This zone of subsidence covered about 285,000 square kilometers, including the north and west parts of Prince William Sound, the west part of the Chugach Mountains, most of Kenai Peninsula, and almost all the Kodiak Island group.


damage photoFive-story J.C. Penney Building, 5th Avenue and Downing Street, Anchorage, Alaska, partly collapsed by the March 28, 1964 earthquake. Note undamaged buildings nearby.






damage photo
Landslide and slumping effects in the Turnagain Heights area, Anchorage, Alaska, caused by the March 28, 1964, earthquake.






This shock generated a tsunami that devasted many towns along the Gulf of Alaska, and left serious damage at Alberni and Port Alberni, Canada, along the West Coast of the United States (15 killed), and in Hawaii. The maximum wave height recorded was 67 meters at Valdez Inlet. Seiche action in rivers, lakes, bayous, and protected harbors and waterways along the Gulf Coast of Louisiana and Texas caused minor damage. It was also recorded on tide gages in Cuba and Puerto Rico.

This great earthquake was felt over a large area of Alaska and in parts of western Yukon Territory and British Columbia, Canada.

 this  is a picture of what happend after a earthquake happend.


 this is a picture of the san andreas fault. One of the worlds most dangerous fault line in the world this is in California. If this fault was to have a magitude 7.8 or higher most of California,Oregon,Washingtion and part of Canada would be destoryed.





this is a picture of a famliy after a earthquake in South Asia. This famliy lost everything they owned. What they are living in right now is whats left of their house. They are sleeping under whats left of the roof.

















Early Saturday morning an earthquake measuring 7.6 struck, and affected Pakistan, India and surrounding countries. It is now reported that over 30,000 people are feared dead, with tens of thousands injured and an un-estimated number displaced.  Entire villages in the North West Frontier Province (NWFP) and Pakistan-administered Kashmir, also known as Azaad Jammu and Kashmir (AJK), are said to have been destroyed or severely damaged.  Large-scale destruction of homes and schools are reported from areas in NWFP and AJK (see map of earthquake impact on the right).  Numerous aftershocks have continued to hit the affected region since Saturday morning’s earthquake. It has been immediately evident that the situation in India also represents a substantial operation. An initial assessment from Save the Children in India found heavy casualties, especially in the two most affected districts of Baramulla and Kupwara.

It is very clear that there is a great need for shelter and food on a large scale. Governments in the region are appealing for international assistance. As winter fast approaches the affected mountainous region, timely provision of assistance becomes even more critical.  Medical supplies and support are needed as the injured begin to trickle out of the worst-hit areas.  Migration of displaced populations has begun with reports of families packing their belongings and thousands moving by foot out of the worst affected areas.

As in most disasters, children are severely affected. The earthquake struck as the Saturday morning session of school was underway and many children and their teachers died in collapsed buildings. Towns and villages are speaking of a ‘lost generation.’ Children who survived or were not at school have lost family members and have been separated from their families; they have sustained injuries that require short and long term treatment; they have lost friends and play spaces, as well as access to education and health (http://www.savethechildren.org.au/australia/what_we_do_programs/emergencies/earthquake_south_asia.html)







Earthquake Area Map. (Map courtesy of BBC News.The delineation of international boundaries on this map must not be considered authoritative.)






















Earthquakes in the San Francisco Bay Region result from strain energy constantly accumulating across the region because of the northwestward motion of the Pacific Plate relative to the North American Plate (Figure 1 ). The region experienced large and destructive earthquakes in 1838, 1868, 1906, and 1989, and future large earthquakes to relieve this continually accumulating strain are a certainty. For our study we define the SFBR as extending from Healdsburg on the northwest to Salinas on the southeast.  It encloses the entire metropolitan area, including its most rapidly expanding urban and suburban areas. We have used the term "major" earthquake as one with M>=6.7 (where M is moment magnitude). As experience from recent earthquakes in Northridge, California (M6.7, 1994, 20 killed, $20B in direct losses) and Kobe, Japan (M6.9, 1995, 5500 killed, $147B in direct losses), earthquakes of this size can have a profound impact on the social and economic fabric of densely urbanized areas. (says http://earthquake.usgs.gov/regional/nca/wg02/index.php)





Faults and Plate motion

Faults and plate motions in the San Francisco Bay Region. Faults in the region, principally the seven faults shown here and characterized in this report, accommodate about 40 mm/yr of mostly strike-slip motion between the Pacific and North American tectonic plates. Yellow lines show the locations of the 1868 M6.8 earthquake on the southern portion of the Hayward Fault and the 1989 M6.9 Loma Prieta earthquake near the San Andreas fault northeast of Monterey Bay (says http://earthquake.usgs.gov/regional/nca/wg02/index.php)








 Earthquakes occurring in Qeshm Island during the past 2 years.

(solar year)



Local Time












Southwest  of Payposht








North of Darghahan








Southeast of Berke Khalaf








Northwest of Basaiedoo
(outside Qeshm island)








This figure shows is a composite image from GRACE satellite data showing the gravity changes for the Sumatra-Andaman earthquake. Image courtesy of Shin-Chan Han Ohio State University.


 For the first time, scientists have been able to use satellite data to detect the changes in the earth's surface caused by a massive earthquake. The discovery, reported in the latest issue of the journal Science, signifies a new use for the data from NASA's two GRACE satellites and offers a possible new approach to understanding how earthquakes work. (says http://www.physorg.com/news73836406.html)





What to Do During an Earthquake

Stay as safe as possible during an earthquake. Be aware that some earthquakes are actually foreshocks and a larger earthquake might occur. Minimize your movements to a few steps to a nearby safe place and stay indoors until the shaking has stopped and you are sure exiting is safe.

If indoors

  • DROP to the ground; take COVER by getting under a sturdy table or other piece of furniture; and HOLD ON on until the shaking stops. If there isn’t a table or desk near you, cover your face and head with your arms and crouch in an inside corner of the building.
  • Stay away from glass, windows, outside doors and walls, and anything that could fall, such as lighting fixtures or furniture.
  • Stay in bed if you are there when the earthquake strikes. Hold on and protect your head with a pillow, unless you are under a heavy light fixture that could fall. In that case, move to the nearest safe place.
  • Use a doorway for shelter only if it is in close proximity to you and if you know it is a strongly supported, loadbearing doorway.
  • Stay inside until shaking stops and it is safe to go outside. Research has shown that most injuries occur when people inside buildings attempt to move to a different location inside the building or try to leave.
  • Be aware that the electricity may go out or the sprinkler systems or fire alarms may turn on.
  • DO NOT use the elevators.

If outdoors

  • Stay there.
  • Move away from buildings, streetlights, and utility wires.
  • Once in the open, stay there until the shaking stops. The greatest danger exists directly outside buildings, at exits, and alongside exterior walls. Many of the 120 fatalities from the 1933 Long Beach earthquake occurred when people ran outside of buildings only to be killed by falling debris from collapsing walls. Ground movement during an earthquake is seldom the direct cause of death or injury. Most earthquake-related casualties result from collapsing walls, flying glass, and falling objects.

If in a moving vehicle

  • Stop as quickly as safety permits and stay in the vehicle. Avoid stopping near or under buildings, trees, overpasses, and utility wires.
  • Proceed cautiously once the earthquake has stopped. Avoid roads, bridges, or ramps that might have been damaged by the earthquake.

If trapped under debris

  • Do not light a match.
  • Do not move about or kick up dust.
  • Cover your mouth with a handkerchief or clothing.
  • Tap on a pipe or wall so rescuers can locate you. Use a whistle if one is available. Shout only as a last resort. Shouting can cause you to inhale dangerous amounts of dust.

(infomation from http://www.fema.gov/hazard/earthquake/eq_during.shtm




What to Do Before an Earthquake

Earthquakes strike suddenly, violently and without warning. Identifying potential hazards ahead of time and advance planning can reduce the dangers of serious injury or loss of life from an earthquake. Repairing deep plaster cracks in ceilings and foundations, anchoring overhead lighting fixtures to the ceiling, and following local seismic building standards, will help reduce the impact of earthquakes.

Six Ways to Plan Ahead

  1. Check for Hazards in the Home
    • Fasten shelves securely to walls.
    • Place large or heavy objects on lower shelves.
    • Store breakable items such as bottled foods, glass, and china in low, closed cabinets with latches.
    • Hang heavy items such as pictures and mirrors away from beds, couches, and anywhere people sit.
    • Brace overhead light fixtures.
    • Repair defective electrical wiring and leaky gas connections. These are potential fire risks.
    • Secure a water heater by strapping it to the wall studs and bolting it to the floor.
    • Repair any deep cracks in ceilings or foundations. Get expert advice if there are signs of structural defects.
    • Store weed killers, pesticides, and flammable products securely in closed cabinets with latches and on bottom shelves.
  2. Identify Safe Places Indoors and Outdoors
    • Under sturdy furniture such as a heavy desk or table.
    • Against an inside wall.
    • Away from where glass could shatter around windows, mirrors, pictures, or where heavy bookcases or other heavy furniture could fall over.
    • In the open, away from buildings, trees, telephone and electrical lines, overpasses, or elevated expressways.
  3. Educate Yourself and Family Members
    • Contact your local emergency management office or American Red Cross chapter for more information on earthquakes. Also read the "How-To Series" for information on how to protect your property from earthquakes.
    • Teach children how and when to call 9-1-1, police, or fire department and which radio station to tune to for emergency information.
    • Teach all family members how and when to turn off gas, electricity, and water.
  4. Have Disaster Supplies on Hand
    • Flashlight and extra batteries.
    • Portable battery-operated radio and extra batteries.
    • First aid kit and manual.
    • Emergency food and water.
    • Nonelectric can opener.
    • Essential medicines.
    • Cash and credit cards.
    • Sturdy shoes.
  5. Develop an Emergency Communication Plan
    • In case family members are separated from one another during an earthquake (a real possibility during the day when adults are at work and children are at school), develop a plan for reuniting after the disaster.
    • Ask an out-of-state relative or friend to serve as the "family contact." After a disaster, it's often easier to call long distance. Make sure everyone in the family knows the name, address, and phone number of the contact person.
  6. Help Your Community Get Ready
    • Publish a special section in your local newspaper with emergency information on earthquakes. Localize the information by printing the phone numbers of local emergency services offices, the American Red Cross, and hospitals.
    • Conduct a week-long series on locating hazards in the home.
    • Work with local emergency services and American Red Cross officials to prepare special reports for people with mobility impairments on what to do during an earthquake.
    • Provide tips on conducting earthquake drills in the home.
    • Interview representatives of the gas, electric, and water companies about shutting off utilities.
    • Work together in your community to apply your knowledge to building codes, retrofitting programs, hazard hunts, and neighborhood and family emergency plans

                  (infomation from http://www.fema.gov/hazard/earthquake/eq_before.shtm)





Statistics of the Great Alaskan Earthquake of 1964

On Good Friday, March 27, 1964, at 5:36 PM local time in Alaska, an earthquake with a magnitude of 9.2 struck Prince William Sound. Not only was this earthquake the second largest recorded in the world, it lasted approximately 4 to 5 minutes which is unusually long. Within the first 24 hours, there were 11 aftershocks and with a magnitude greater than 6.0 and 9 more took place over the next few weeks. In total, there were over 10,000 aftershocks.

Cause of the Great Alaskan Earthquake of 1964

Coastal Alaska is on a fault zone where the Pacific plate meets the North American plate. The earthquake took place on a thrust fault where the Pacific plate slips underneath the North American plate. It was determined that the slip of the continental plate took place 16 miles underground. The epicenter was near Prince William Sound which is situated between Valdez and Anchorage.

The ground clay turned to liquid and caused it to become unstable. This is a process called liquefaction. Fissures opened up as more solid ground dropped, rose up and tilted. Some residents claimed the ground waves were over 3 feet high.

Cities and Towns Most Affected by the Great Alaskan Earthquake of 1964

Anchorage suffered the most damage because of liquefaction:

  • An area of clay bluffs, called Turnagain Heights collapsed and over 75 homes were lost.
  • Part of the main street sunk into a 10 foot hole and extensive damage was done to buildings in a 30 block radius.
  • The façade at the J.C.Penney store broke away from the building and crashed into the street, killing two people.
  • An apartment building and several schools collapsed.
  • The air traffic control tower at the Anchorage airport fell over, killing the controller.
  • Water, sewer and gas lines ruptured plus telephone and electrical service were disrupted.
  • Nine deaths were reported.

Valdez: is located 120 miles east of Anchorage:

  • A freighter at the town dock was being unloaded. The wave created by the earthquake entered the harbor and lifted the freighter 30 feet. There were 28 people killed at the dock and the freighter broke free into the harbor.
  • Many waterfront homes and commercial buildings were destroyed.
  • Large waves continued at 30 minute cycles for the next 9 hours.
  • The waves combined with high tide, caused extensive flooding.


  • Located 80 miles south of Anchorage, it also experienced huge harbor waves and flooding.
  • The biggest catastrophe was the fires that broke out. Tanks at a large oil storage facility exploded and sent flames across the harbor.
  • Twelve people died.

Kodiak Island:

  • It was not damaged by the earthquake but it was hit by very large harbor waves.
  • The water in the harbor suddenly receded and it sunk down to 2 feet, leaving fishing boats sitting on the bottom. This was caused by the pulling of the waves.
  • When the waves struck, the boats were tossed into the town, some of them 3 blocks from the harbor.
  • Two canneries were wiped out.
  • Eight people died.

Tsunami Caused by the Great Alaskan Earthquake of 1964

The uplift of the ocean floor generated a tsunami with an estimated speed of 400 miles per hour. This caused more deaths in areas outside of Alaska. The tsunami went across the Pacific as far as the Hawaiian Islands. Along the North American coast, there were waves that caused extensive property damage.

  • The worst hit was Port Alberni British Columbia Canada where the wave funneled through an inlet and it washed away 55 homes and damaged 375 others. Nobody was killed.
  • There were 12 people killed in Crescent City California and 4 died in Beverly Beach State Park in Oregon. Other coastal towns and cities (including Hawaii) also suffered damage.

It was fortunate that the death toll was very small considering the size of the earthquake. This was due to the low density of population in Alaska. Because it was Good Friday many businesses and schools were closed. It is also a good thing that many of the buildings in Alaska were built out of wood because it is a more flexible material.


Related Articles:

Glacier Bay Alaska, karefree@morguefile.com








1964 March 28 03:36:14 UTC (local time: March 27 05:36:14 p.m.)
Magnitude 9.2


Largest Earthquake in Alaska



Damage Photos



Photo of earthquake
Close-up of Government Hill elementary school, which was destroyed by the Government Hill landslide. Anchorage, Alaska.

Photo of earthquake
The waterfront at Seward a few months after the earthquake, looking north. Note the "scalloped" shoreline left by the underwater landslides that severed tracks in the railroad yard which dangle over the landslide scarp and the windrow-like heaps of railroad cars and other debris thrown up by the tsunami waves. Alaska.

Photo of earthquake
Uplifted sea floor at Cape Cleare, Montague Island, Prince William Sound, in the area of greatest recorded tectonic uplift on land (33 feet). The very gently slopping flat rocky surface with the white coating which lies between the cliffs and the water is about a quarter of a mile wide. It is a wave cut surface that was below sea level before the earthquake. The white coating consists of the remains of calcareous marine organisms that were killed by desiccation when the wave cut surface was lifted above the high tide during the earthquake.

Photo of earthquake
Uplifted dock on Hinchinbrook Island, Prince William Sound. Land in this area rose about 8 feet during the earthquake, and the dock can now be used only at extremely high tides.

Photo of earthquake
The stumps in the foreground are part of an ancient forest on Latouche island, Prince William Sound, that was submerged below sea level and buried in prehistoric times. Tectonic uplift of 9 feet during the earthquake raised these stumps above sea level once again, demonstrating that the area is tectonically restless.

Photo of earthquake
The amount of tectonic uplift on Glacier Island, Prince William Sound, was shown by the upper limit to which algae of the intertidal zone are on this sea cliff before and after the earthquake. The top of the band of green (still living) algae is near present (post earthquake) mean high tide. The top of the band of brown (desiccated) algae marks the approximate position of mean high tide before the earthquake. The difference in height between the top of the bands of living and of desiccated algae (3 feet) is a measure of the amount of tectonic uplift in this area.

Photo of earthquake
View southwest along the Hanning Bay fault scarp on southwest Montague Island in Prince William Sound. The Hanning Bay fault was reactivated during the earthquake. Its trace is marked by 10 to 15 feet high bedrock scarp which trends obliquely across the field of view from the right foreground to the left background. The fault trace lies between the uplifted wave cut surface that is coated white by desiccated calcareous marine organisms and borders the open ocean and the area of brown sand and silt in the cove. The ground northwest of the fault (right side of photo) was displaced upward as much as 16 feet with respect to the ground southeast of the fault during the earthquake, but both sides of the fault were uplifted with respect to sea level due to general tectonic uplift of the region. The fault plane dips steeply NW, or is vertical.

Photo of earthquake
Close-up view of tsunami damage along the waterfront at Kodiak.

Photo of earthquake
The Hillside apartment building in Anchorage was severely damaged by the earthquake and has been razed. It was a split-level, five story building with steel posts and lintels, concrete floor slabs, and unreinforced concrete block walls and partitions.




Photo of earthquake
One span of the "Million Dollar" truss-bridge of the former Copper River and Northwestern Railroad was dropped into the Copper River by the earthquake, and the other truss spans were shifted on their piers.

Photo of earthquake
The earthquake shifted the steel trusses of the Copper River and Northwestern Railroad bridge near Round Island from 1 to 2 feet. This view shows one of the displaced trusses, which pounded against an adjacent steel girder span. The girder span was moved to the right, its concrete pedestal was rotated, and the girder span almost fell into the river. Note the shortening indicated by buckling of the guardrail.

Photo of earthquake
A series of earthquake triggered landslides in glacial deposits disrupted almost a mile of The Alaska Railroad main line at Potter Hill, near Anchorage.

Photo of earthquake
Close-up of damaged homes at Turnagain Heights landslide, Anchorage.

Photo of earthquake
A subsidence trough (or graben) formed at the head of the "L" Street landslide in Anchorage during the earthquake. The slide block, which is virtually unbroken ground to the left of the graben, moved to the left. The subsidence trough sank 7 to 10 feet in response to 11 feet of horizontal movement of the slide block. The volume of the trough is theoretically equal to the volume of the void created at the head of the slide by movement of the slide block. A number of houses seen in this photograph were undercut or tilted by subsidence of the graben. Note also the collapsed Four Seasons apartment building and the undamaged three story reinforced concrete frame building beside it, which are on the stable block beyond the graben.

Photo of earthquake
A detail illustrating the violence of the surge waves that struck Whittier: man holds mounted tire where wave has driven a piece of wood through the tire.

Photo of earthquake
Trees up to 24 inches in diameter and between 88 and 101 feet above sea level were broken and splintered by the surge wave generated by an underwater landslide in Port Valdez, Prince William Sound.

Photo of earthquake
The rails in this approach to a railroad bridge near the head of Turnagain Arm were torn from their ties and buckled laterally by channelward movement of the river banks during the earthquake. The bridge was also compressed and developed a hump from vertical buckling.

Photo of earthquake
The rails were buckled by lateral movement of the embankment fill toward an underlying culvert, which had collapsed.




Photo of earthquake
House displaced by compressional ridge formed at toe of L Street landslide Anchorage district. Cook Inlet region, Alaska. 1964.


Photo of earthquake
Control tower at Anchorage International Airport, collapsed by earthquake shaking. Anchorage district, Cook Inlet region, Alaska.


Photo of earthquake
Close-up view of the damage created at the piers of the "Million Dollar" truss bridge by movement of the truss spans during the earthquake. Note the bent base plates, the sheared 2-inch diameter bolts and the overturned rocker bars.

Photo of earthquake
The Turnagain Heights landslide in Anchorage, occurred along a steep bluff fronting Knik Arm of Cook Inlet. Its length, which is parallel to the bluff, was about 1.5 miles; its width was about .25 to .50 miles. This landslide reduced to rubble many of the finer homes of the city. Failure here, and in the "L" Street, Fourth Avenue, and Government Hill landslides in Anchorage occurred on horizontal or near horizontal slip surfaces in the Bootlegger Cove Clay, a marine silt of Pleistocene age. Alaska.

Photo of earthquake
This reinforced concrete deck of highway bridge across Twenty Mile River near Turnagain Arm of Cook Inlet fell into the river during the earthquake; the adjacent steel railroad bridge survived with only minor damage. Both bridges were founded on thick deposits of soft alluvium and tidal flat mud, and were subjected to severe seismic vibration. During the earthquake some of the concrete deck sections hit the underlying wood pilling with sufficient force to drive the bare ends of the wood piles through the concrete deck.

Photo of earthquake
The marquee of the Denali Theater, which was in the graben of the Fourth Avenue landslide in Anchorage, subsided until it came to rest on the sidewalk in front of the theater, which was on ground that was not involved in the landslide.

Photo of earthquake
This truck at Lowell Point, 2 miles from Seward, was bent around a tree by the surge waves generated by the underwater landslides along the Seward waterfront. The truck was about 32 feet above water level at the time of the earthquake.

Photo of earthquake
Collapse of Fourth Avenue near C Street, Anchorage, due to earthquake caused landslide. Before the earthquake, the sidewalk at left, which is in the graben, was at street level on the right. The graben subsides 11 feet in response to 14 feet of horizontal movement. Anchorage district, Cook Inlet region, Alaska. 1964



(pictures by http://earthquake.usgs.gov/regional/states/events/1964_03_28_pics_2.php)                                               




December 27, 2004

Asian Earthquake Disaster Kills 44,000

(AP) - Bodies washed up on tropical beaches and piled up in hospitals Monday, raising fears of disease across a 10-nation arc of destruction left by a monster earthquake and walls of water that killed more than 44,000 people. Thousands were missing and millions homeless. Humanitarian agencies began what the United Nations said would become the biggest relief effort the world has ever seen.                                                                                                                    

Poster of the Sumatra-Andaman Islands Earthquake of 26 December 2004 - Magnitude 9.0

26 December 2004 Earthquake

Larger ImagePDF version




The devastating earthquake of 26 December 2004 occurred as thrust-faulting on the interface of the India plate and the Burma microplate. In a period of minutes, the faulting released elastic strains that had accumulated for centuries from ongoing subduction of the India plate beneath the overriding Burma microplate.

In a broad sense, the India and Australian plates move toward the north-northeast with respect to the interior of the Eurasia plate with velocities of about 60 mm/y in the region of the earthquake. This results in oblique convergence at the Sunda trench. The oblique motion is partitioned into thrust-faulting, which occurs on the interface between the India plate and the Burma microplate and involves slip directed at a large angle to the orientation of the trench, and strike-slip faulting, which occurs on the eastern boundary of the Burma microplate and involves slip directed approximately parallel to the trench. Details of the velocity of the Burma microplate remain to be determined and may, in fact, be clarified by further analysis of the December main shock and its aftershocks.

Currently available models of the 26 December main-shock fault displacement differ in many interesting details, but are consistent in implying that fault-rupture propagated to the northwest from the epicenter and that substantial fault-rupture occurred hundreds of kilometers northwest of the epicenter. The data upon which the modeling is based do not permit confident resolution of the extent of rupture beyond about 500 km northwest of the main-shock epicenter. The finite fault model shown here implies that the width of the earthquake rupture, measured perpendicular to the Sunda trench, was about 150 kilometers, and that the maximum displacement on the fault plane was about 20 meters. The sea floor overlying the thrust fault would have been uplifted by several meters as a result of the earthquake.

The zone of aftershocks to the 26 December earthquake is over 1300 km long. Because aftershocks occur on and very near the fault planes of main shocks, the length of the aftershock zone suggests that main-shock fault-rupture may have extended north of epicenter by an amount significantly larger than 500 km. However, a great earthquake may also trigger earthquake activity on faults that are distinct from the main-shock fault plane and separated from it by tens or even hundreds of kilometers. We will not know until further analysis how much of the 26 December aftershock zone may correspond to activity in the immediate vicinity of the main-shock rupture, and how much may correspond to activity remote from the main-shock rupture.

Since 1900, earthquakes similarly sized or larger than the 26 December earthquake have been the magnitude 9.0 1952 Kamchatka earthquake, the magnitude 9.1 1957 Andreanof Islands, Alaska, earthquake, the magnitude 9.5 1960 Chile earthquake, and the magnitude 9.2 1964 Prince William Sound, Alaska, earthquake. All of these earthquakes, like the 26 December earthquake, were mega-thrust events, occurring where one tectonic plate subducts beneath another. All produced destructive tsunamis, although deaths and damage from the 26 December tsunami have far exceeded those caused by tsunamis associated with the earlier earthquakes.







Richter scale read-out Nowhere in the world is immune from large-scale earthquakes, experts said today, in the wake of "significant" tremors that shook buildings in Lincolnshire and Yorkshire in the early hours.


The UK's largest earthquake for 24 years was centred around the town of Market Rasen in Lincolnshire and happened at just before 1am this morning. The British Geological Survey (BGS) confirmed a magnitude of 5.2 local magnitude (ML) on the Richter scale.


A geophysicist from the United States Geological Survey (USGS) said that while the event was "light to moderate" on a world scale, it was significant for a country not normally considered to be a seismic hot spot.


Rafael Abreu, said: "What is interesting about this event is that it was in an area where you would not expect it. In an aseismic area like this it is very significant.


"The UK usually has minor activity - it's not particularly seismic and usually falls in the range of two to three (on the Richter scale). Usually something in the range of four to five is what you would expect closer to a tectonic boundary - Indonesia or California for example."


However, Mr Abreu added that no area was immune from strong earthquake activity. "Recently we had a 6.3 event in Nevada which was the first one there," he said.


"These are events which are rare, but one of those things that can happen. The truth is that it can happen anywhere in the world, any place in the world."


Minor damage

Just one person was seriously injured as a result of last night's earthquake, according to reports today. Student David Bates was watching television in the attic of his home in Barnsley Road, Wombwell, South Yorkshire, when he was struck by a piece of masonry. It was reported that he fractured his pelvis.


Other than that there were widespread reports of minor damage. Norwich Union confirmed that policyholders had already began to get in touch concerning damage to their properties.


Jason Harris, senior claims manager at Norwich Union, said: "We have seen a number of claims coming in to our call centres overnight, but we expect further calls today as damage will be more obvious in daylight.


"At the moment these are reports of mainly minor damage such as tiles off roofs, breakages inside the home and brick walls collapsing."


The good news for property owners is that they should be covered by their insurance. Earthquakes, are normally covered as standard in both contents and buildings insurance. In addition, repair costs to vehicles hit by falling masonry would normally be covered if the driver has fully comprehensive car insurance.


Earthquake history

The BGS said it records around 200 earthquakes in the UK each year. It added that earthquakes of the size recorded last night occur in the mainland UK around every 30 years, but are more common in offshore areas.


Last night's was the largest since 1984 when an earthquake measuring 5.4 on the Richter scale shook the Lleyn Peninsula of north Wales and was widely felt across England and Wales. Last April, residents in Kent were hit by a tremor registering 4.2 ML.


The largest earthquake ever recorded in the UK happened about 75 miles north-east of Great Yarmouth in the North Sea on 7 June 1931, measuring 6.1 ML.




(says http://www.nurs.co.uk/news/articles/cms/12041310812126947321009_1.htm)



Earthquakes strike suddenly, without warning. Earthquakes can occur at any time of the year and at any time of the day or night. On a yearly basis, 70 to 75 damaging earthquakes occur throughout the world. There are in excess of 200 significant earthquakes in New Zealand alone every year plus many more minor ones.  Whilst not all these are devastating earthquakes, there have been several severe earthquakes.  On February 3, 1931 a devastating earthquake measuring 7.9 on the Richter scale hit the Napier/Hastings areas causing a death toll of 258. This earthquake had 525 aftershocks in the following two weeks. Two major earthquakes have hit Wellington one on the 16 October, 1848 measuring 7.1 and another 6 years later on 23 January, 1855 measuring 8.0, fortunately although there was severe damage to property the death toll was minor.  The opinion of the authorities is that it is a matter of when not if the next “big one” will happen.


1.1         What Are Earthquakes, and What Causes Them?

An earthquake is a sudden, rapid shaking of the Earth caused by the breaking and shifting of rock beneath the Earth's surface. For hundreds of millions of years, the forces of plate tectonics have shaped the Earth as the huge plates that form the Earth's surface move slowly over, under, and past each other. Sometimes the movement is gradual. At other times, the plates are locked together, unable to release the accumulating energy. When the accumulated energy grows strong enough, the plates break free causing the ground to shake. Most earthquakes occur at the boundaries where the plates meet; however, some earthquakes occur in the middle of plates.


Ground shaking from earthquakes can collapse buildings and bridges; disrupt gas, electric, and phone service; and sometimes trigger landslides, avalanches, flash floods, fires, and huge, destructive ocean waves (tsunamis). Buildings with foundations resting on unconsolidated landfill and other unstable soil, and homes not tied to their foundations are at risk because they can be shaken off their mountings during an earthquake. When an earthquake occurs in a populated area, it may cause deaths and injuries and extensive property damage.


The Northridge, California, earthquake of January 17, 1994, struck a modern urban environment generally designed to withstand the forces of earthquakes. Its economic cost, nevertheless, has been estimated at $20 billion. Fortunately, relatively few lives were lost. Exactly one year later, Kobe, Japan, a densely populated community less prepared for earthquakes than Northridge, was devastated by the most costly earthquake ever to occur. Property losses were projected at $96 billion, and at least 5,378 people were killed. These two earthquakes tested building codes and construction practices, as well as emergency preparedness and response procedures. 


Where earthquakes have occurred in the past, they will happen again. Learn whether earthquakes are a risk in your area and learn about your communities warning systems and emergency plans and what you need to do.


Ground movement during an earthquake is seldom the direct cause of death or injury. Most earthquake-related injuries result from collapsing walls, flying glass, and falling objects as a result of the ground shaking, or people trying to move more than a few feet during the shaking. Much of the damage in earthquakes is predictable and preventable.  


1.2         What to Do During an Earthquake


Drop, cover, and hold on!

Move only a few steps to a nearby safe place. A safe place could be under a sturdy table or desk or against an interior wall away from windows, bookcases, or tall furniture that could fall on you. An interior wall is less likely to collapse than a wall on the outside shell of the building. Hold on, and protect your eyes by pressing your face against your arm. Most injured persons in earthquakes move more than ten feet during the shaking. It is very dangerous to try to leave a building during an earthquake because objects can fall on you. Many fatalities occur when people run outside of buildings, only to be killed by falling debris from collapsing walls.  The shorter the distance to move to safety, the less likely you will be injured.


If you are in bed

Hold on and stay there, protecting your head with a pillow. You are less likely to be injured staying where you are. Broken glass on the floor has caused injury to those who have rolled to the floor or tried to get to doorways.


If you are outdoors

Find a clear spot away from buildings, trees, streetlights, and power lines. Drop to the ground and stay there until the shaking stops. Injuries can occur from falling trees, street-lights and power lines, or building debris.


If you are in a vehicle

Pull over to a clear location, stop and stay there with your seatbelt fastened until the shaking has stopped. Trees, power lines, poles, street signs, and other overhead items may fall during earthquakes. Stopping will help reduce your risk, and a hard-topped vehicle will help protect you from flying or falling objects. Once the shaking has stopped, proceed with caution. Avoid bridges or ramps that might have been damaged by the quake.


Stay indoors until the shaking stops and you're sure it's safe to exit.

More injuries happen when people move during the shaking of an earthquake. After the shaking has stopped, if you go outside, move quickly away from the building to prevent injury from falling debris. Stay away from windows, they can shatter with such force that you can be injured several feet away.


In a high-rise building, expect the fire alarms and sprinklers to go off during a quake.

Earthquakes frequently cause fire alarm and fire sprinkler systems to go off even if there is no fire. Check for and extinguish small fires, and, if exiting, use the stairs and not the lifts.


If you are in a coastal area

Move to higher ground. Tsunamis are often created by earthquakes.


If you are in a mountainous area or near unstable slopes or cliffs

Be alert for falling rocks and other debris that could be loosened by the earthquake. Landslides commonly happen after earthquakes.


If you're outside in an earthquake

Stay outside. Move away from buildings, trees, streetlights, and power lines. Crouch down and cover your head. Many injuries occur within 10 feet of the entrance to buildings. Bricks, roofing, and other materials can fall from buildings, injuring persons nearby. Trees, streetlights, and power lines may also fall, causing damage or injury

1.3         What to Do After an Earthquake


Expect aftershocks.

Aftershocks are smaller earthquakes that follow the main shock and can cause further damage to weakened buildings. After-shocks can occur in the first hours, days, weeks, or even months after the quake. Be aware that some earthquakes are actually foreshocks, and a larger earthquake might occur.


Check yourself for injuries.

Often people tend to others without checking their own injuries. You will be better able to care for others if you are not injured or if you have received first aid for your injuries.

Protect yourself from further danger by putting on long pants, a long-sleeved shirt, sturdy shoes, and work gloves. This will protect you from further injury by broken objects. Move carefully and watch out for things that have fallen or broken, creating hazards


After you have taken care of yourself, help injured or trapped persons.

Give first aid when appropriate. Don't try to move seriously injured people unless they are in immediate danger of further injury.


Look for and extinguish small fires. Eliminate fire hazards.

Putting out small fires quickly, using available resources, will prevent them from spreading. Fire is the most common hazard following earthquakes. Fires following the Hasting/Napier earthquake in 1931 caused considerable damage and loss of life. Fires followed the San Francisco earthquake of 1906 for three days, creating more damage than the earthquake. Avoid smoking inside buildings. Smoking in confined areas can cause fires or explosions if gas or chemicals have leaked.


Leave the gas on at the main valve, unless you smell gas or think it is leaking. Turn it off if in doubt.

 It may be weeks or months before professionals can turn gas back on using the correct procedures. Explosions have caused injury and death when homeowners have improperly turned their gas back on by themselves.  Clean up spilled medicines, bleaches, gasoline, or other flammable liquids immediately. Avoid the hazard of a chemical emergency.


Open closet and cabinet doors cautiously.

Contents may have shifted during the shaking of an earthquake and could fall, creating further damage or injury.


Inspect your home for damage. Get everyone out if your home is unsafe.

Aftershocks following earthquakes can cause further damage to unstable buildings. If your home has experienced damage, get out before aftershocks happen.


Help neighbours who may require special assistance.

Elderly people and people with disabilities may require additional assistance. People who care for them or who have large families may need additional assistance in emergency situations.


Listen to a portable, self powered radio (or television) for updated emergency information and instructions.

If the electricity is out, this may be your main source of information. Local radio and local officials provide the most appropriate advice for your particular situation.


Expect aftershocks.

Each time you feel one, drop, cover, and hold on! Aftershocks frequently occur minutes, days, weeks, and even months following an earthquake.


Watch out for fallen power lines or broken gas lines, and stay out of damaged areas.

Hazards caused by earthquakes are often difficult to see, and you could be easily injured.


Stay out of damaged buildings.

If you are away from home, return only when authorities say it is safe. Damaged buildings may be destroyed by aftershocks following the main quake.


Use dynamo, solar or battery-powered lanterns or flashlights to inspect your home.

Kerosene lanterns, torches, candles, and matches may tip over or ignite flammables and leaking gas inside.


Inspect the entire length of chimneys carefully for damage.

Unnoticed damage could lead to fire or injury from falling debris during an aftershock. Cracks in chimneys can be the cause of a fire years later.  Take pictures of the damage, both to the house and its contents, for insurance claims.


When entering buildings use extreme caution.

Building damage may have occurred where you least expect it. Carefully watch every step you take. Examine walls, floor, doors, staircases, and windows to make sure that the building is not in danger of collapsing.


Ø       Check for gas leaks. If you smell gas or hear a blowing or hissing noise, open a window and quickly leave the building. Turn off the gas, using the outside main valve if you can, and call the gas company from a neighbour’s home. If you turn off the gas for any reason, it must be turned back on by a professional.

Ø       Look for electrical system damage. If you see sparks or broken or frayed wires, or if you smell burning insulation, turn off the electricity at the main fuse box or circuit breaker. If you have to step in water to get to the fuse box or circuit breaker, call an electrician first for advice.

Ø       Check for sewage and water line damage. If you suspect sewage lines are damaged, avoid using the toilets and call a plumber. If water pipes are damaged, contact the water company and avoid using water from the tap. You can obtain safe water from undamaged water heaters or other water storage containers.

Ø       Watch for loose items. Plaster, drywall, and ceilings that could fall.


Use the telephone only to report life-threatening emergencies.

Telephone lines are frequently overwhelmed in disaster situations. They need to be clear for emergency calls to get through.


Watch animals closely. Leash dogs and place them in a fenced yard.

The behaviour of pets may change dramatically after an earthquake. Normally quiet and friendly cats and dogs may become aggressive or defensive.

1.4         How to Protect Your Property 


Quake Safe Your Home - Fix. Fasten. Forget.

It is important to secure items to prevent injury during and after an earthquake

Ø       Secure hot water cylinders and header tanks

Ø       Check that your house is secured to its foundations

Ø       Secure your chimney with galvanised metal bands

Ø       Secure wood burners and gas appliances to the floor

Ø       Install flexible pipe fittings to avoid gas or water leaks. Flexible fittings will be less likely to break.

Ø       Store heavy objects low down

Ø       Use non-slip mats or plastic putty such as Blu Tack under smaller appliances and objects

Ø       Push picture and mirror hooks closed

Ø       Install strong latches and bolts on cabinets to prevent doors opening and contents falling out.

Ø       Have flexible gas and plumbing fittings installed.

Ø       Bolt bookcases, china cabinets, and other tall furniture to wall studs.

Ø       Brace or anchor high or top-heavy objects. During an earthquake, these items can fall over, causing damage or injury.

Ø       Secure items that might fall (televisions, books, computers, etc.). Falling items can cause damage or injury.

Ø       Move large or heavy objects and fragile items (glass etc) to lower shelves

Ø       Store breakable items such as bottled foods, glass, and china in low, closed cabinets with latches. Latches will help keep contents of cabinets inside.

Ø       Store weed killers, pesticides, and flammable products securely in closed cabinets with latches, on bottom shelves. Chemical products will be less likely to create hazardous situations from lower, confined locations.

Ø       Hang heavy items, such as pictures and mirrors, away from beds, couches, and anywhere people sit. Earthquakes can knock things off walls, causing damage or injury.

Ø       Brace overhead light fittings to prevent falling

Ø       Repair any deep cracks in ceilings or foundations. Get expert advice if there are signs of structural defects. Earthquakes can turn cracks into ruptures and make smaller problems bigger.

(infomation from http://www.survive-it.co.nz/info2.php?digistore_custid=6c960644feb7f9f5470aaa18ebdc133d)



Reverse faults

Reverse faults are associated with compressional forces- 2 plates or fault blocks pushing towards each other. One side ends up on top! Thrust faults are reverse faults that move up a shallower angle than ordinary reverse faults.


Strike-slip faults


Strike-slip faults are associated with shear stresses. One side of the fault "slides" past the other. "Sometimes" it is fairly easy to recognize where movement on a strike-slip fault has occurred. The photo below shows a creek located along the San Andreas Fault. The zigzag effect (offset) of the creek channel is the result of movement along the fault.

Compare the photo of the San Andreas Fault with the strike-slip fault diagram. The San Andreas Fault is a right-lateral strike-slip fault. (infomation from http://wapi.isu.edu/envgeo/EG5_earthqks/eg_mod5.htm)


Kentucky's Earthquake Record Book

A large has formed in the road during an earthquake

Kentucky has experienced hundreds, if not thousands of earthquakes in the past.  Geologists have found evidence of earthquakes from millions of years ago.

Since record keeping only started in the past several hundred years, we do not have a complete record of the shaking that has taken place.  Below you will find some historical background on of some of the earthquakes that have been recorded in Kentucky.

There are several seismic zones in and around the state; the most significant is the New Madrid Seismic Zone (NMSZ) located at the border of western Kentucky.  Scientists estimate that the probability of a magnitude 6 to 7 earthquake occurring in this seismic zone within the next 50 years is higher than 90%.

 While the last significant earthquake, a 5.1 on the Richter scale near Sharpsburg in Bath County in 1980, caused an estimated $3 million in damage the most notable earthquakes in Kentucky occurred along the NMSZ from December 1811 to March 1812.  Three of the largest earthquakes in the contiguous United States occurred along the NMSZ over this period and an engineer in Louisville recorded 1,850 shocks over this period.  The shocks from these earthquakes could be easily felt as far away as Detroit, Michigan, and South Carolina.  An area between the St. Francois River and Mississippi River running from New Madrid, Missouri to Marked Tree, Arkansas showed numerous sand-blows (a place where liquefacted alluvial soil has geysered out of the surface). 

Liquefaction is a phenomenon where shaking of the ground separates the water from the soil holding it, causing the soil to behave like a dense liquid.  The lack of water causes the soil to lose surface cohesion and molecules of sand from these blows to accumulate  up to five feet in places.  Liquefaction will cause land to lose its load bearing capacity

During the 1811-1812 period areas along the Mississippi River were uplifted as well as subsided.  Opposite New Madrid, the area around Tiptonville, Tennessee formed a dome (uplift of several yards).  Immediately adjacent to the Tiptonville Dome, an area subsided to form a lake eighteen miles long and five miles wide.  It is now known as Reelfoot Lake and is a tourist and recreation area.

Ground failure and landslides were apparent throughout the Chickasaw Bluffs alongside the Mississippi River in Kentucky and Tennessee.  Many fissures were made throughout the region and one local observer recorded that the earth seemed to be rolling in waves several feet in height.  These swells would burst, leaving wide and long fissures.

The damage to the area was so severe that Congress passed, and President James Madison signed into law, the first disaster relief act giving government lands in other territories to people wanting to move out of the effected area.

Earthquakes in the central or eastern United States affect much larger areas than earthquakes of similar magnitude in the western United States.  For example, the San Francisco, California earthquake of 1906 (magnitude 7.8) was felt 350 miles away in the middle of Nevada, whereas the New Madrid earthquake of December 1811 (magnitude 8.0) rang church bells in Boston, Massachusetts, 1,000 miles away.  Differences in geology east and west of the Rocky Mountains cause this strong contrast.

 Although earthquakes in the central and eastern United States are less frequent than in the western United States, they affect much larger areas.  This is shown by two areas affected by earthquakes of similar magnitude, the 1895 Charleston, Missouri, earthquake in the New Madrid seismic zone and the 1994 Northridge, California, earthquake.  Red indicates minor to major damage to buildings and their contents.  Yellow indicates shaking felt, but little or no damage to objects, such as dishes.

( says http://kyem.ky.gov/programs/earthquake/)


Man prays in Kashiwazaki, Japan.

The horrible sight following earthquake in Japan.



TOKYO, Japan -- The death toll from weekend earthquakes in northern Japan has risen to 25, with more than 1,200 others reported injured, authorities reported.

Three earthquakes with magnitudes ranging from 5.9 to 6.8 struck Saturday evening in Niigata prefecture, about 250 kilometes (150 miles) north of Tokyo.

A strong aftershock rattled the area early Monday, but there were no immediate reports of damage or injuries from the magnitude 5.7 tremor.

The death toll was revised after searchers dug into the rubble of collapsed buildings and found more people dead, authorities in Niigata prefecture said.

Later in the day, the said no other people were missing.

More than 1,400 buildings were destroyed in the Saturday's quakes, which caused blackouts, ruptured water mains and collapsed houses around the region.

Hospitals also suffered from blackouts and personnel in those facilities had to remove some of the patients to the outside, local media reports said.

Television pictures showed hundreds of people crammed together under covers and coats in one shelter.

Many complained that they had little or no food, as they waited for supplies to reach the mountainous area, some parts of which have been cut off by landslides, NHK said.

Other residents have begun salvaging belongings from their flattened homes, as hundreds of people suffering injuries overwhelmed local hospitals, which were also suffering from blackouts.

"After the first earthquake, I ran to my shop," one woman said.

"Then the next one hit and I was clinging to a pillar. I ran out with nothing in my hands. All I have left is what I am wearing now."

The earthquakes were strong enough to sway skyscrapers in Tokyo for about a minute.

The first of three temblors was a 6.8-magnitude quake centered in Ojiya. It rocked the area on Saturday evening, knocking a bullet train from its rails and ripping through roadways.

Several strong quakes followed through the night, and aftershocks continued to jolt the area.

The bullet train derailment was the first since such trains began running in Japan in 1964.

A second-floor supermarket collapsed as it was busy with customers.

"There were 300 customers inside when the earthquake hit, and everyone tried to grab something nearby to keep from being knocked off their feet," store manager Reiko Takahashi was quoted by The Associated Press as saying.

Takejiro Hoshino, 75, lost his 12-year-old grandson when their house collapsed.

"I got out and then we all went back to try to save the others, but it was too late," Hoshino said.

Across the state, 61,000 people were evacuated to emergency shelters and in Ojiya, 5,290 people took refuge at 50 different evacuation centers, AP quoted an official as saying.

The temblors came just days after Japan's deadliest typhoon in more than a decade, which left 78 people dead and a dozens missing. (Full story)

Saturday's temblors caused mudslides in areas where the storm's torrential rains had loosened the ground.

Japan is among the world's most earthquake-prone countries.

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