Earthquakes, Landslides Tsunamis
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Tsunami M.L. Anderson, 2009 Tsunami: Giant sea waves Usually produced by earthquakes but can also be caused by submarine landslides or volcanic eruptions. Anchorage: Earthquake & Tsunami Damage Sudden Tsunami movements of the sea floor, which set off waves within the water that travel outward. They are commonly not felt in the open ocean, however, wh en the tsunami approaches shorelines, the waves slow down and water piles up to heights over 65m. Tsunami or Seismic Sea Wave Long wavelengths (> 200 km or 125 m) Shallow-water wave Speed proportional to water depth so very fast in open ocean Sea level can rise up to 40 m (131 ft) when tsunami reaches shore Earthquake Prediction PTWS: Pacific Tsunami Warning System. A network of stations that attempt to identify potentially damaging tsunamis from earthquakes in or around the Pacific Ocean. Issues early warnings especially in Hawaii and Japan. Tsunami Warning System Tsunami Types and Triggers Landslide Earthquake Triggered Submarine Landslide Volcanic Eruption Undersea Mega-thrust Earthquake Landslide Triggered Tsunami Informative kinematics specify position, velocity, and thickness of material that transcends down-slope. With slide shape and thickness, we are able to compute tsunami waves. Landslides Triggered Tsunami On July 17, 1998, an earthquake generated one of the most destructive tsunamis. The earthquake triggered a massive underwater landslide. As a result, people drowned and villages were destroyed. •2,183 People Died •Most of the victims were children. •Thousands Injured •Several Villages completely destroyed The Trigger 7.0 Magnitude Earthquake Caused Landslide which in turn caused Tsunami. 4 waves Lasted 18 minutes 30 ft high waves Earthquake occurred at 6:49pm http://www.drgeorgepc.com/Tsunami1998PNG.html 6:50pm waves hit the shore http://www.briancasseyphotographer.com/images/awards/10.jpg Location of Papua, New Guinea 1. The smaller Caroline plate forces the Australian plate up. 2. Occurred along a steep dipping reverse fault Papua/ New Guinea Faults New Guinea is the site of an arc-continent region where tectonic plates slide or converge past each other. The tectonic boundaries and faulting are complex in this region. walrus.wr.usgs.gov/tsunami/PNG.html) This diagram shows the boundaries and faults in New Guinea. Bathymetry There is a very steep and linear slope located off of the northern shore of New Guinea. This slope could have been a factor for the unusual height of the tsunami that was caused by the earthquake. July 17, 1998 6:49 PM Minutes after the occurrence of the earthquake, four successive tsunami waves hit the coast of Papua/New Guinea. As a result, two villages disappeared and two other villages were destroyed. Trees were ripped out of the ground due to the movement of the waves. Tsunami Waves People had no choice, but to run when they saw the tsunami waves. There were four tsunami waves. The travel time of the first tsunami wave was one minute. The four tsunami waves occurred within a total time of eighteen minutes. Each tsunami wave was short. Each tsunami wave averaged to about four minutes long. Canary Islands; La Palma Landslide Tsunami Cumbre Vieja (Spanish: "Old Ridge") is an active volcanic ridge on the volcanic ocean island of Isla de La Palma in the Canary Islands. Location: Spain. This ridge trends in an approximate north-south direction and covers the southern third of the island. It is lined by several volcanic craters. La Palma landscape La Palma The La Palma landslide slide will involved 500 km3 of material running out to 60 km at a mean speed of 100 m/s. Not if…but when? Landslide & tsunami Sub oceanic landslides are similar to ground landslides, since this involves movement of rock and sediment. Differences between the ground and sub oceanic water is its degree of steepness. Ground inclinations of ~10o are at odds and sea floors of slight inclinations of <~1o are also at risk. Earthquake Triggered Tsunamis 1755 Lisbon, Portu gal A near 9.0 magnitude earthquake occurred 200 km from the Portuguese coast. This earthquake was generated by convergence between the African and Eurasian Plates at a ridge known as Gorringe Bank. The earthquake itself destroyed much of the Portuguese City of Lisbon. Lisbon Earthquake/ Tsunami Several minutes after the earthquake, a minimum of 3 tsunamis, around 10 meters in height, ravaged the city. The waves also hit Spain and North Africa, and did damage in the Azores, Madiera, and the Canary Islands. Its effects were felt as far west as the Caribbean Islands, where 3-5 meter waves were reported, and as far north as Ireland. Submarine Landslide & Earthquake Triggered Tsunami Grand Banks 1929 Puerto Rico 1918 San Pedro, Calif. Pending Santa Barbara, Calif. Pending Algunas, So. Africa 1.8Myo Submarine Landslides The largest landslides on Earth occur underwater. Suboceanic, or submarine landslides can involve the movement of rocks and sediments entirely beneath the sea, or they can begin as partly above-water landslides that later enter the ocean. Like open-air landslides, submarine landslides often strike steep inclines but, unlike open air slides, submarine landslides also hit very slightly dipping terrain. Submarine Landslides Best evidence suggests that the potential for suboceanic landslides exists pretty much globally, whether in tectonically active or tectonically inactive regions. A primary hazard of submarine landslides, like their land bound relatives, is the destruction of man-made structures along their path. Undersea slope failures present an additional threat -- landslide-generated tsunami waves. Earthquake A 7.2 magnitude earthquake struck. Epicenter of 44.5°N, 56.3°W Experienced as far away as New York and Montreal. Seismic waves recorded up in Denmark. http://www.geophys.washingtion.edu/tsunamis/general/historic/grandbanks29. html Grand Banks 1929 / Worst Case Scenario First documented submarine landslide The first recorded sub oceanic landslide was recorded in 1929 near Newfoundland. The landslide created a tsunami and killed nearly 30 people in Nova Scotia and Newfoundland. 100 m/s and retaining 20m height Grand Banks, Newfoundland, 1929 1929 Grand Banks, Newfoundland, C anada - 7.2 magnitude. Earthquake tsunami run- up extended 480 m inland to an elevation of more than 8.5 m above sea level. Broke Trans-Atlantic Cables TransAtlantic cable Damages http://www.usgs.gov/faq/list_faq_by_category/get_answer.asp?id=970 The tsunamis killed 28 people Left 10,000 more homeless The submarine landslide destroyed 12 transatlantic telegraph cables. Geologic Findings The first recognition of submarine landslides ability to cause a tsunami. The first recognition of turbidity currents in a natural environment. This event created a Turbidity Current – a current of rapidly moving, sediment-laden water moving down a slope through air, water, or another fluid. http:en.wikipedia.org/wiki/Turbidity_current Geological Evidence Photographs of 1929 tsunami deposits at Taylor's Bay on Newfoundland's southern coast. Photograph shows three sandy units deposited by consecutive waves. http://earthquakescanada.nrcan.gc.ca/histor/20th-eme/1929/1929-eng.php 1918 - Puerto Rican Submarine Landslide A 7.5 magnitude earthquake off of the Puerto Rican Trench. The deepest point in the W. Atlantic, produced waves and run- up on the order of 4-6 m. It killed 40 people. Caused surges in water levels at tide gauges: Atlantic City, NJ. Pending Disaster San Pedro Landslide & tsunami Submarine slope failures and active faults, all of which can generate tsunamis, are known on the shelf and slope of San Pedro. Large slope failures are present on the San Pedro Escarpment and on the basin slope. The escarpment has a long history of slope failures. San Pedro Landslide & tsunami The San Pedro Bay is home to the largest container ports in the United States. A large earthquake or tsunami would seriously impact California’s economy and the nations. The major earthquake could cause seafloor uplift of eight feet or more. San Pedro Landslide & tsunami These areas of restraining bends created uplift on the sea floor. During an earthquake, these bends can push the seafloor up and generate a tsunami. Submarine landslide complex in the Santa Barbara Channel in the vicinity of Goleta, California The Goleta Submarine Landslide Complex is located in the Santa Barbara Channel near Coal Oil Point near Goleta and Santa Barbara. The image was generated from a multibeam-bathametric data. It shows large tongues of sediment created by undersea landslides that extend in some places more than 6 miles (10 kilometers) onto the seafloor in the Santa Barbara Channel from their source of failure along the margin near the break in slope of the continental shelf edge. Past Submarine landslide in the Santa Barbara Channel Research shows that record submarine landslide failures in the Santa Barbara area began about 200,000 years ago, with two of the large landslide slope having formed about 10,000 and 8,000 years ago. Scientists are concerned that such offshore landslides could cause tsunamis that affect the Santa Barbara coast with little advanced warning. Past Submarine landslide in the Santa Barbara Channel Scientist Gary Greene, head of the research notes: "This slide evidently moved in three different events. Each event displaced enough sediment to be capable of generating a tsunami, if the displacements occurred rapidly.“ Resulting maps revealed submarine landslides along the northern flank of the basin. Greene was able to map in detail a large, 130 km slump off Coal Oil Point near Goleta. This prominent slump is 14.6 km long by 10.5 km wide and extends from 90 meters to a depth of 570 meters. Algunas Submarine Landslide, So. Africa The largest documented slope failure. Distance landslide traveled is 140 km The Agulhas submarine Landslide occurred after the Pliocene Epoch which ended nearly 1.8 million years ago. Volcanic Eruption Krakatoa, Indonesia 1883 Sunset in England, 1883 It caused a drop in global temperatures for 5 years. The airborne particles led to spectacular sunsets for years. The eruption produced a black cloud of volcanic debris that blocked out all sunlight in the region for 3 days. It reduced incoming solar radiation worldwide by 10%. Krakatoa, Indonesia 1883 Krakatau eruption (1883) in The explosion destroyed the Indonesia - killed more than entire island. 36,000 people It created a huge tsunami that killed thousands of people that were trying to seek shelter from the ash, rock and debris that was raining down on them. In it’s place , “The son of Krakatoa” is now growing up from the ocean floor. Every bit as dangerous as it’s father, today it violently spits out gas, ash and pyroclastic rock. Sumatran Undersea Mega Thrust Earthquake December 26, 2004 at 7:58AM Magnitude 9.1 – 9.3 Epicenter was off the west coast of Sumatra, Indonesia Undersea mega thrust earthquake Occurred at subduction zone at convergent plate boundry Estimated 994 mile long fault line ruptured about 50 feet On the morning of 12/26/04 at 7:58:49 am, M 9.0 earthquake ~100 km (60 mi) off W. Coast Northern Sumatra, Indonesia. A huge landslide of the West coast caused by a underwater earthquake is how the Tsunami began. Sumatran Undersea Mega Thrust Earthquake Set off massive waves 1200 km section of (“tsunami”) that raced earth’s crust shifted towards the west and east. ~10-20 mi beneath the Over a period of 10 Indian Ocean. hours, tsunami struck Quake released stored coasts of over 12 countries. elastic energy equal to Major damage and deaths ~23,000 Hiroshima around the Indian atomic bombs. Ocean, from Southeast Asia Uplifted the sea floor to Africa. several meters, One of the most displacing billions of devastating disasters in modern human history. gallons of seawater. The Earthquake Second largest earthquake ever recorded Energy released similar to 9,560 gigatons of TNT Aftershocks felt for up to 3 to 4 months after the quake Largest aftershock Registered a magnitude of 8.7 Produced its own aftershock The Earthquake Felt as far away as Bangladesh, Malaysia, Myanmar, Thailand, Singapore, M aldives Earthquake lasted 8.3 to 10 minutes long Longest earthquake ever observed Entire planet vibrated ~1cm The Tsunami Earthquake triggered a series of tsunami waves Hardest hit were Indonesia, Sri Lanka, India and Thailand Waves Reached nearly 100 feet in height Traveled ~1.24 miles inland Sea receded as far as 1.6 miles Took 15 minutes to 7 hours to reach various coastlines The Tsunami The tsunami wave reached as far as South Africa Approx. 5,300 miles away 16 hours later Resulted in the death of ~225,000 people across 11 countries 1/3 were children 4x more women died than men US Military Helicopter takes this shot of a town near the coast of Sumatra that lies in ruin, on January 2, 2005. DEATH TOLLS FROM TSUINAMI 2004 As of February 22, 2005 the Thailand – 5,395 dead w/ death toll stood at 169,752 2,993 missing. people dead with, 127,294 Somalia – 82 dead w/ 26 people listed as missing. missing. The death tool stood as Malaysia – 68 dead. follows: Myanmar – 59 dead. Indonesia – 122,232 dead Tanzania – 10 dead with 113,937 missing. according to the UN. Sri Lanka – 30,974 dead Seychelles – 3 dead still missing 4,697 w/ according to the UN. 100,000 families displaced. Bangladesh - 2 dead India – 10,766 dead with according to the UN. 5,640 missing. Kenya – 1 dead according to Kenya Media. Photo taken by Henrvk Kotowski on December 26, 2004, showing the aftermath. There was ample time to issue warning, HOWEVER, no warning system existed for this part of the world! Effects of Earthquakes Before & After Impact Dampening Coral reefs Destroyed by inhabitants to make way for fisherman and shrimp farmers Tsunamis would have rushed against the reef, lessening power Mangrove Trees Removed along the coastline for residences Could have blocked much of the incoming force The significance of coral reefs and mangrove swamps and dunes Many countries across Asia have played a significant role in the destruction caused by the Tsunami, by destroying the coral surroundings of their beaches to make way for economics- shrimp farming. On Surin Island Chain of Thailand's coast many people were saved as the tsunami rushed against the coral reefs protecting the islands. The removal of coastal mangrove trees has also intensified the effect of tsunami waves in some locations. Another factor relating to an increase in damage is the removal of coastal sand dunes. EARTHQUAKE The only recorded earthquakes with larger Mw than the Sumatran earthquake, were the 1960 Chilean and the 1964 Alaskan earthquakes. The shock waves of the earthquake was felt across the planet, as far away as Oklahoma where vertical movements of 3mm was recorded. The sudden vertical rise of the seabed by several meters during the earthquake, displaced massive volumes of water, resulting in a Tsunami that struck the coasts of the Indian Ocean. A Wake-up Call We as people contribute to our own environments natural breakdown of resilience. Nothing could have prevented this phenomena, but the manner in which we choose to use our resources could have lessen the impact of this natural disaster. References http://www.wikipedia.com http://www.ess.washington.edu/tsunami/sumatra.htm http://www.csupomona.edu/~marshall/ind_oc_tsunami_lec.v4.htm www.geo.arizona.edu images.google.com http://www.mbari.org/news/news_releases/2000/dec15_greene.html www.es.ucsc.edu/~ward/papers/ward&day.pdf www.tsunamis.com Real pictures of tsunami www.wsspc.org.com Western States Seismic Policy Council en.wikipedia.org Tsunami News.nationalgeographic.com/news/2004/12/1227_041226_tsunami.htm Tsunami Sumatra 2004 References http://walrus.wr.usgs.gov/tsunami/itst.html http://www.drgeorgepc.com/tsunami1998PNG.html http://walrus.wr.usgs.gov/tsunami/png.html http://www.sfgate.com •1929 Grand Banks Earthquake: http:en.wikipedia.org/wiki/1929_Grand_Banks_earthquake; •The 1929 Grand Banks Landslide and Tsunami Revisited: http://adsabs.harvard.edu /abs/2006AGUFMOS33E..05M;. •The 1929 Grand Banks Tsunami: http://www.geophys.washingtion.edu/tsunamis /general/historic/grandbanks29. html;. Grand Banks: http://www.aquatic.uoguelph.ca/oceans/atlanticoceanweb /AOFloor/Grandbanks.htm;. •Grand Banks: http://earthquakescanada.nrcan.gc.ca/histor/20th-eme/1929/1929- •How Do Landslides Create Tsunamis?: http://www.usgs.gov/faq/list_faq_by_category /get_answer.asp?id=970;. •Turbidity Current: http:en.wikipedia.org/wiki/Turbidity_current;.