T-SUNAMI AND IT'S

DAMAGESBy Sarthak HatwarClass XIth a

What is tsunami

Tsunamis are giant waves, initiated by a sudden change (usually in relative position of underwater tectonic plates). The sudden change is typically enough to propagate the wave; however, its power can be enhanced and fed by lunar positioning and boundaries that focus its energy.

1st April, 1946, Aleutian Earthquake and Tsunami The Aleutian Islands Earthquake occurred near Unimak

Island in Alaska's Aleutian Island Chain and was followed by a Pacific-wide tsunami. This earthquake had a magnitude of 7.8 on the Richter scale, with its epicenter at 52.8 degree N, 163.5 degree W, and focal depth of 25 km. A gigantic wave of 35 meters destroyed completely the U.S. Coast Guard's Scotch Cap lighthouse on Unimak and killed all five of its occupants. The lighthouse was a steel-reinforced concrete structure standing about 30 meters above sea level. The tsunami caused 165 casualties and about 26 million dollar in damages. The tsunami is known as the April Fools Day Tsunami in Hawaii as people took the tsunami warning as an April Fool prank.

he 4 November, 1952, Kamchatka Earthquake and Tsunami

A strong earthquake (magnitude 8.2) off the coast of Kamchatka Peninsula generated a great destructive Pacific-wide tsunami. Its waves struck the Kamchatka Peninsula, the Kuril Islands and other areas of Russia's Far East, causing considerable damage and loss of life. The tsunami was widely observed and recorded in Japan, but there was no loss of life or damage there. There was considerable damage in the Hawaiian Islands and some damage in Peru and Chile. The tsunami was recorded or observed throughout the islands of the Pacific. In New Zealand waves reached height of 1m, and in Alaska, in the Aleutian Islands and in California waves of up to 1.4 meters were observed. The largest waves outside the generating area were observed in the Hawaiian Islands. Fortunately, no human lives were lost in Hawaii from this tsunami, but damages were extensive, ranging from $800,000- $1,000,000. In the Hawaiian island chain, the tsunami waves destroyed boats and piers, knocked down telephone lines, and caused extensive beach erosion

The north shore of the Island of Oahu experienced higher waves of up to 4.5 meters. On the south shore of the island, tsunamis waves were powerful enough to throw a cement barge in the Honolulu Harbor into a freighter. The island of Hawaii experienced drag up to 6.1 meters. In Hilo, a small bridge connecting Coconut Island to the shore was destroyed by one of the tsunami waves lifting it off its foundation, then smashing it down. The effects of the tsunami in the generating area in Kamchatka, varied significantly. From Kamchatka Peninsula to Kronotsky Peninsula, the wave heights ranged from 0 to 5 meters. From Kronotsky Peninsula to Cape Shipursky the heights ranged from 4-13 meters. The highest wave of 13 meters was the third as observed at Olga Bay, where it caused considerable damage. Travel time of the first tsunami wave to Olga Bay was approximately 42 minutes after the earthquake. From Cape Shipursky to Cape Povorotny, the tsunami waves ranged from 1 to 10 meters and caused considerable loss of life and damage. At Avachinskaia Bay the tsunami height was 1.2 meters and its travel time was about 30 minutes. From Cape Povorotny to Cape Lopatkka the waves ranged from 5 to 15 meters

At Khodutka Bay a cutter was thrown 500 meters back from shore. On the West coast of Kamchatka Peninsula, the maximum tsunami run up at Ozernoe was 5 meters. At Alaid Island of the Kuril Island group, run up was 1.5 meters, while at Shumshu Island it ranged from 7-9 meters. At Paramushir Island, the waves ranged from 4-18.4 meters. At Severo - Kurilsk on Paramushir Island, the second wave was the highest reaching maximum run up of 15 meters. It destroyed most of the town and caused considerable loss of life. At Onekotan Island tsunami run up was 9 meters, while at Shiashkoton Island it was 8 meters and at Iturup Island 2.5 meters. Waves of up to 2 meters were observed at the Komandorsk Islands and at Okhotsk. At Sakhalin - Korsakov a 1-meter tsunami wave was observed.

13 January 2001 tsunami Although the earthquake of 13 January 2001 occurred

along a subduction area known for its tsunamigenic potential, the reason that a destructive tsunami was not generated may be that the depth of focus of this particular event was rather deep at 39 km. The focal depth and epicenter location indicate that this earthquake was probably along the Beniof Zone rather than along the subducting boundary where shallow focus events cause large vertical displacements of the ocean floor. As more seismic data becomes available, a source mechanism study will be undertaken to determine why a significant tsunami was not generated and to understand better the seismotectonic coupling and tsunamigenesis of the Cocos tectonic plate in this particular region of Central America.

Tsunami of October 10, 2002 in Irian Jaya, Indonesia

A local tsunami was generated. The waves ranged in height from 3-5 meters along the coast of Manokwari, Oranbari and Ransiki.

The 2003 Hokkaido tsunami

On September 25, 2003, a magnitude (M) 8.3 offshore earthquake struck Hokkaido, Japan. The earthquake and ensuing tsunami injured 589 people and resulted in significant damage to port and coastal communities. In 1952, a similar earthquake in terms of epicentral location and magnitude (M 8.1) occurred along this part of the Kuril subduction zone.

These two earthquakes are referred to as the 1952 and 2003 Tokachi-Oki earthquakes. Their similarity allows scientists to determine:

how the rupture mechanics of an earthquake affects a subsequent earthquake in the same location

how details of nearly identical earthquakes affect tsunami runup and inundation, and

how quantitative assessments of ground failure perform during a major earthquake.

During his time at the USGS, Kenji worked with scientists from both the CMG team and the Earthquake Hazards team to examine the rupture mechanics of the 1952 Tokachi-Oki earthquake, as determined from tide-gauge records of the tsunami.

The 2004 Indian Ocean earthquake Waves of up to 10.5 meters in height

struck Northern Sumatra, the Nicobar and Andaman Islands, Thailand, Sri Lanka, India. Destructive waves also struck the Maldives, Somalia, Kenya and the islands off the African coast. The tsunami was recorded by tide gauge stations not only in the Indian Ocean, but in the Pacific as well. In Manzanillo, Mexico, the tide gauge recorded a wave of 2.6 meters.

Eighteen (18) countries bordering the Indian Ocean were

affected by the tsunami. These were: Indonesia, Thailand, India, Sri-Lanka, Malaysia, Myanmar, Bangladesh, Maldives, Reunion Island (French), Seychelles, Madagascar, Mauritius, Somalia, Tanzania, Kenya, Oman, South Africa and Australia.

Tsunami of 2005  quick succession, a magnitude-9.0 earthquake struck

offshore of Sumatra on Dec. 26, followed by tsunami waves that traveled across the Indian Ocean to overwhelm villages and beaches in Thailand, Malaysia, Somalia, India and elsewhere. As of Jan. 14, more than 155,000 people had been reported dead, with thousands of people still missing, and disease threatening to kill thousands more.

NASA scientists measured a 2.5-centimeter shift of the North Pole. The total vertical and horizontal displacement on the thrust fault probably was at least 15 meters.

The tsunami of 17 July 2006

The tsunami which hit the island of Java (Indonesia) on 17 July 2006 was caused by an earthquake of a magnitude of Mw=7.7. It occurred at 8:19:25 (UTC, Coordinated Universal Time). The coordinates of the epicentre are 9.311° S, 107.284° E (USGS), located to the south of Java. The calculated depth of the hypocenter is 48.6 km.

ust like the Sumatra earthquake of 26 December 2004, this earthquake occurred in a sector of the subduction zone along which the Australian plate is sliding under the Sunda plate at a rate of 59 mm/year. The first reasonable estimates of the size of the fault could be: length=100 km, width=50 km, slip along fault =2.5 m. The tsunami affected an area of approximately 150 km along the south coast in this tsunami

 525 are dead and 383 injured

2007 Solomon Islands At least fifty-two people were reported to have been killed

and sixty reported missing when a tsunami triggered by the earthquake struck the Solomon Islands, wiping out thirteen or more villages.[2][3] Thousands were left homeless, and damages are estimated in millions. The largest waves were reported on the northern tip of Simbo Island, where maximum tsunami run-ups were 12 m, completely washing away two villages, Tapurai and Riquru, and killing 10 people.[4] In South Choiseul, waves 10 meters high swept away villages, gardens and a hospital.[5] About 900 homes were destroyed.[6]

September 29, 2009 Somoa Quake and Tsunami

the Samoa Islands were hit by a 7.9 M earthquake at 17:48 UTC (6:48 AM local time) on September 29, 2009. The epicenter was 139 miles SW of Pago Pago, American Somoa. The resulting tsunami caused considerable damage in both Somoa and in American Somoa. Over 150 people are estimated to have been killed as the coastal areas of all the Samoan islands were inundated. Casualties were reported from Somoa, American Somoa and Tonga. American Somoa is a US territory and has been declared a disaster area by President Obama.

October 2010 Sumatra earthquake and tsunami

The October 2010 Sumatra earthquake was a magnitude 7.7 Mw

[1] earthquake, which occurred on 25 October 2010 off the western coast of Sumatra Indonesia at 21:42 local time (14:42 UTC).[4] The earthquake occurred on the same fault that produced the 2004 Indian Ocean earthquake. It was widely felt across the provinces of Bengkulu and West Sumatra and resulted in a substantial localized tsunami that struck the Mentawai Islands.[5]

Many villages on the islands were affected by the tsunami, which reached a height of 3 m (9 ft) and swept as far as 600 m (1800 ft) inland. The tsunami caused widespread destruction that displaced more than 20,000 people and affected about 4,000 households. 435 people were reported to have been killed, with over 100 more still missing.[3] The subsequent relief effort was hampered by bad weather[6] and the remoteness of the islands, which led to delays in the reporting of casualties.[7]

Daybreak was expected to reveal the full extent of the death and damage from Friday's 8.9 magnitude earthquake and the 10-meter high tsunami it sent surging into cities and villages, sweeping away everything in its path.In one of the worst-hit residential areas, people buried under rubble could be heard calling out "help" and "when are we going to be rescued," Kyodo news agency reported.

The government warned there could be a small radiation leak from a nuclear reactor whose cooling system was knocked out by the quake. Prime Minister Naoto Kan ordered an evacuation zone around the plant be expanded to 10 km (6 miles) from 3 km. Some 3,000 people had earlier been moved out of harm's way.

 huge devastation in tsunami-hit Japan

Underscoring concerns about the Fukushima plant, 240 km (150 miles) north of Tokyo, U.S. officials said Japan had asked for coolant to avert a rise in the temperature of its nuclear rods, but ultimately handled the matter on its own. Officials said a leak was still possible because pressure would have to be released.The unfolding natural disaster prompted offers of search and rescue help from 45 countries.China said rescuers were ready to help with quake relief while President Barack Obama told Japanese Prime Minister Naoto Kan the United States would assist in any way."This is likely to be a humanitarian relief operation of epic proportions," Japan expert Sheila Smith of the U.S.-based Council on Foreign Relations wrote in a commentary.

The northeastern Japanese city of Kesennuma, with a population of 74,000, was hit by widespread fires and one-third of the city was under water, Jiji news agency said on Saturday.The airport in the city of Sendai, home to one million people, was on fire, it added.TV footage from Friday showed a muddy torrent of water carrying cars and wrecked homes at high speed across farmland near Sendai, 300 km (180 miles) northeast of Tokyo. Ships had been flung onto a harbor wharf, where they lay helplessly on their side.Boats, cars and trucks were tossed around like toys in the water after a small tsunami hit the town of Kamaichi in northern Japan. Kyodo news agency reported that contact had been lost with four trains in the coastal area.Japanese politicians pushed for an emergency budget to fund relief efforts after K