Duty : Report text About Natural Disaster

tsunami

By : Azizah Fitriani Class : XI IPA 8

2011 Tōhoku earthquake and tsunami The 2011 earthquake off the Pacific coast of Tohoku, also known as the 2011 Tōhoku earthquake or the Great East Japan Earthquake, (Japanese: "Eastern Japan Great Earthquake Disaster" (東日本大震災 , Higashi Nihon Daishinsai?)[fn 1]) was a magnitude 9.0 (Mw) undersea megathrust earthquake off the coast of Japan that occurred at 14:46 JST (05:46 UTC) on Friday, 11 March 2011, with the epicenter approximately 70 kilometres (43 mi) east of the Oshika Peninsula of Tōhoku and the hypocenter at an underwater depth of approximately 32 km (20 mi). It was the most powerful known earthquake to have hit Japan, and one of the five most powerful earthquakes in the world overall since modern record-keeping began in 1900. The earthquake triggered extremely destructive tsunami waves of up to 40.5 metres (133 ft) in Miyako, Iwate, Tōhoku. In some cases traveling up to 10 km (6 mi) inland. In addition to loss of life and destruction of infrastructure, the tsunami caused a number of nuclear accidents, primarily the ongoing level 7 meltdowns at three reactors in the Fukushima I Nuclear Power Plant complex, and the associated evacuation zones affecting hundreds of thousands of residents.

Japanese Prime Minister Naoto Kan said,

"In the 65 years after the end of World War II,

this is the toughest and the most difficult

crisis for Japan." The Japanese

National Police Agency has confirmed 15,780

deaths, 5,929 injured, and 4,122 people

missing across eighteen prefectures, as well as

over 125,000 buildings damaged or destroyed.

The earthquake and tsunami caused extensive

and severe structural damage in Japan,

including heavy damage to roads and railways

as well as fires in many areas, and a dam

collapse. Around 4.4 million households in

northeastern Japan were left without

electricity and 1.5 million without water.

Many electrical generators were taken

down, and at least three nuclear reactors

suffered explosions due to hydrogen gas that

had built up within their outer containment

buildings after cooling system failure.

Residents within a 20 km (12 mi) radius of

the Fukushima I Nuclear Power Plant and a

10 km (6.2 mi) radius of the

Fukushima II Nuclear Power Plant were

evacuated. In addition, the U.S. recommended

that its citizens evacuate up to 80 km (50 mi)

of the plant.

Early estimates placed insured losses from

the earthquake alone at US$14.5 to $34.6

billion. The Bank of Japan offered ¥15 trillion

(US$183 billion) to the banking system on 14

March in an effort to normalize market

conditions. The overall cost could exceed

US$300 billion, making it the most expensive

natural disaster on record.

The earthquake moved Honshu 2.4 m

(8 ft) east and shifted the Earth on its axis by

estimates of between 10 cm (4 in) and 25 cm

(10 in).

Earthquake

The 9.0-magnitude (MW) undersea megathrust

earthquake occurred on 11 March 2011 at

14:46 JST (05:46 UTC) in the western Pacific

Ocean at a relatively shallow depth of 32 km

(19.9 mi), with its epicenter approximately

72 km (45 mi) east of the Oshika Peninsula of

Tōhoku, Japan, lasting approximately six

minutes. The nearest major city to the quake

was Sendai, on the main island of Honshu,

130 km (81 mi) away. The quake occurred

373 km (232 mi) from Tokyo.

The main earthquake was preceded by a

number of large foreshocks, and hundreds of

aftershocks were reported. The first major

foreshock was a 7.2 MW event on 9 March,

approximately 40 km (25 mi) from the location

of the 11 March quake, with another three on

the same day in excess of 6.0 MW. Following the

quake, a 7.0 MW aftershock was reported at

15:06 JST, followed by a 7.4 at 15:15 JST and a

7.2 at 15:26 JST. Over eight hundred

aftershocks of magnitude 4.5 or greater have

occurred since the initial quake.

Aftershocks follow Omori's Law, which states

that the rate of aftershocks declines with the

reciprocal of the time since the main quake.

The aftershocks will thus taper off in time but

could continue for years. One minute before

the earthquake was felt in Tokyo, the

Earthquake Early Warning system, which

includes more than 1,000 seismometers in

Japan, sent out warnings of impending strong

shaking to millions. It is believed that the early

warning by the Japan Meteorological Agency

(JMA) saved many lives.

The warning for the general public was

delivered about 8 seconds after the first P wave

was detected, or about 31 seconds after the

earthquake occurred. However, the estimated

intensities were smaller than the actual ones in

some places in Kanto and Tohoku regions. This

was thought to be because of smaller estimated

earthquake magnitude, smaller estimated fault

plane, shorter estimated fault length, not

having considered the shape of the fault, etc.

Initially reported as 7.9 MW by the USGS,

the magnitude was quickly upgraded to 8.8,

then again to 8.9, and then finally to 9.0.

Tsunami The earthquake which was caused by 5 to

8 meters upthrust on a 180-km wide seabed at

60 km offshore from the east coast of Tōhoku

resulted in a major tsunami which brought

destruction along the Pacific coastline of Japan's

northern islands and resulted in the loss of

thousands of lives and devastated entire towns.

The tsunami propagated across the Pacific, and

warnings were issued and evacuations carried out.

In many countries bordering the Pacific, including

the entire Pacific coast of North and South

America from Alaska to Chile; however, while the

tsunami was felt in many of these places, it

caused only relatively minor effects.

.

Chile's section of Pacific coast is one of

the furthest from Japan, at about 17,000 km

(11,000 mi) away, but still was struck by

tsunami waves 2 m (6.6 ft) high. A wave

height of 38.9 meters (128 ft) was estimated

at Omoe peninsula, Miyako city, Iwate

prefecture.

That'S all And Thank you.