April 2, 2014

A magnitude-8.2 earthquake slammed northern Chile last night, setting off a tsunami that forced tens of thousands of people to evacuate the country’s 2,650-mile- (4,260-kilometer-) long coastline. Waves as high as 6 feet (2.1 meters) were reported in some areas as well as along the Peruvian coast. The coasts of Peru, Ecuador, Colombia, Panama, Costa Rica, and Nicaragua were put on alert, and an advisory was issued for Hawaii. However, no major damage was reported. Electric power failed across much of Arica, a port city of about 200,000 people. The death toll across the region remains uncertain.

The quake was felt as far away as Bolivia’s capital, La Paz, some 300 miles (480 kilometers) from the earthquake’s epicenter off the coast near the Chilean copper mining city of Iquique, which is also a major port. During an evacuation in that city, some 300 prisoners escaped from a woman’s prison.

An earthquake occurs when Earth’s rock suddenly breaks and shifts, releasing energy in vibrations called seismic waves. The point on Earth where the rock first breaks is called the focus. The point on the surface above is known as the epicenter. (World Book illustration)

A tsunami can occur when an underwater earthquake displaces a large part of the sea floor. In this illustration, a tsunami wave spreads from a fast-rising section of ocean floor. The rising plate lifts the water above it, raising a hump of water that quickly ripples outward. As the ripple enters shallow water, it slows and grows in height. (World Book illustration by Matt Carrington)

Chile lies in one of the world’s most earthquake-prone zones. In 2010, a magnitude-8.8 earthquake off the coast of central Chile left more than 500 people dead. In 1960, a magnitude-9.5 earthquake hit off Chile’s coast near the city of Valdivia. More than 1,600 people were killed, largely from a subsequent tsunami. Seismologists believe the 1960 quake was the largest of the 20th century.

Additional World Book articles:

• Plate tectonics
• Big Waves: Tracking Deadly Tsunamis (a special report)
• When the Earth Moves (a special report)
• Chile 1960 (a Back in Time article)
• Chile 2010 (a Back in Time article)

September 4, 2013

Radiation levels around tanks in which contaminated water is stored at Japan’s crippled Fukushima nuclear power plant have risen to a new high. Ground readings near one set of tanks hit 2,200 millisieverts (mSv) yesterday, up from 1,800 mSv on August 31. (The sievert is the International System of Units [SI] unit that measures the dosage of absorbed radiation that produces biological effect.) Nuclear scientists believe that the 2,200 mSV reading is high enough to provide a lethal radiation dose within hours of exposure.

Tokyo Electric Power Company, which operates the plant, reported in early August that highly contaminated water was leaking from a storage tank. Other leaks have since been reported. Yesterday, the Japanese government announced that it would spend $473 million to build a wall of frozen earth around the damaged nuclear reactors using pipes filled with coolant.

A huge wave strikes Japan's coast on March 11, 2011. An earthquake that day caused a tsunami (series of powerful ocean waves) that caused widespread destruction on Honshu, Japan's largest island (Mainichi Shimbun, Reuters).

A massive earthquake and subsequent tsunami in March 2011 damaged the cooling systems to three Fukushima plant reactors, which went into meltdown. To cool these reactors, water is constantly being pumped over them. However, storing the resulting large quantities of radioactive water has proved a difficult challenge.

Additional World Book articles:

• Radiation sickness
• Japan 2011 (a Back in Time article)
• Reconsidering Nuclear Power (a special report)

August 23, 2013

The discovery that highly radioactive water is leaking from a storage tank at Japan’s crippled Fukushima Daiichi Nuclear Power Station has further alarmed scientists already gravely concerned about conditions at the site. The tank is 1 of 1,000 built to store the massive amounts of water being used to cool the fuel rods from nuclear reactors damaged by a magnitude-9 earthquake and subsequent tsunami that hit Japan’s main island, Honshu, on March 11, 2011. Three of the six reactors at Fukushima went into full meltdown after the plant’s cooling system was knocked out.

The storage tanks at Fukushima, which are about 85 percent filled, currently hold a total of about 80 million gallons (300 million liters) of contaminated water. The leaking tank has released about 80,000 gallons (300,000 liters), most of which has seeped into the ground. Inspectors said the leak resulted from deteriorating plastic seams on the tanks. The leaking tank is one of 350 temporary steel-plated vessels constructed to expand the storage capacity for contaminated water. The other tanks are welded steel vessels. The problem with the storage tank led Japan’s nuclear energy watchdog agency to raise the threat level at the plant from one to three on the International Nuclear and Radiological Event Scale. Conditions at the plant were rated seven–the highest rating–after the tsunami.

A huge wave strikes Japan's coast on March 11, 2011. An earthquake that day caused a tsunami (series of powerful ocean waves) that crippled the Fukushima Daiichi nuclear plant. (© Mainichi Shimbun, Reuters)

News of the leak has strengthened the belief of many scientists that conditions at the plant are much worse than the Japanese government and and Tokyo Electric Power Company (TEPCO), the plant’s operator, are admitting. The leak has also intensified criticism of TEPCO for failing to contain leaks from the plant.

The tanks are only one focus of concern. One nuclear safety expert was quoted by the BBC as saying that contaminated water was leaking everywhere at the site, “not just from the tanks. It is leaking out from the basements, it is leaking out from the cracks all over the place.” According to a Japanese government official, as much as 75,000 gallons (284,000 liters) of groundwater is believed to be flowing daily downhill through the ruined plant and into a containment pond. Despite efforts to hold the contaminated water in the pond, some appears to be flowing into the Pacific Ocean. At a recent news conference, the head of Japan’s nuclear regulation agency expressed concerns about future leaks. Shunichi Tanaka told reporters, “We should assume that what has happened once could happen again, and prepare for more.”

Additional World Book articles:

• Japan 2011 (a Back in Time article)
• Reconsidering Nuclear Power (a special report)

August 9, 2013

Prime Minister Shinzo Abe of Japan has directed his government to step in and do whatever is necessary to stabilize the damaged Fukushima Daiichi nuclear plant. His move throws a glaring light on the fact that the plant’s operator, Tokyo Electric Power Company (TEPCO), has failed to contain nuclear radiation leaks more than two years after a catastrophic triple meltdown caused by an earthquake and tsunami. A magnitude-9 earthquake and subsequent tsunami that hit Japan’s main island, Honshu, on March 11, 2011, knocked out the plant’s cooling systems, triggering blasts at three of six reactors. The earthquake and disaster also left 15,800 people dead and more than 2,600 others missing. Hundreds of thousands of people were left homeless.

A huge wave strikes Japan's coast on March 11, 2011. An earthquake that day caused a tsunami (series of powerful ocean waves) that crippled the Fukushima Daiichi nuclear plant. (© Mainichi Shimbun, Reuters)

According to a government official, as much as 75,000 gallons (284 cubic meters) of  groundwater is believed to be flowing daily downhill through the ruined plant and into a containment pond. In June, TEPCO created a “chemical wall” to line the pond by treating the soil to make it impermeable to water. For a time, the pond contained the contaminated water, but now the water has filled the pond and appears to be flowing over the top of the barrier and into the Pacific Ocean. Nuclear scientists suggest that one solution would be to build a wall of ice around the damaged reactor buildings. This would freeze the surrounding soil, shutting off the flow of groundwater into the plant.

Additional World Book articles:

• Japan 2011 (a Back in Time article)
• Reconsidering Nuclear Power (a special report)

June 19, 2013

Dangerously high levels of toxic radioactive isotopes have been found in groundwater at Japan’s Fukushima nuclear plant, according to the Tokyo Electric Power Company (Tepco) that operates the utility. Tests have shown that strontium 90 is present at 30 times the legal limit and that the radioactive isotope tritium is at 8 times an acceptable level. Tepco officials informed the Japanese media that levels of strontium in groundwater at the Fukushima plant had increased 100-fold since the end of last year.

Three of six nuclear reactors at Fukushima went into full meltdown after a massive earthquake and tsunami on March 11, 2011, crippled the plant’s cooling system. More recently, Fukushima has undergone a series of water leaks and power failures. Radioactive water was found leaking from a storage tank earlier this month. Scientists note that the detection of increasing levels of highly radioactive strontium 90 indicates that Tepco has yet to fully contain the Fukushima reactors.

The tsunami (series of powerful ocean waves) that struck Japan's coast on March 11, 2011, flooded the Fukushima nuclear power plant, causing the meltdown of three of the six reactors. (© Mainichi Shimbun, Reuters)

At the current levels found in the groundwater at Fukushima, strontium 90 has a half-life of 29 years. In humans, this means that the element will continue to irradiate them for years to come. It concentrates in human bone, where it is believed to cause cancer. Tritium, once used on glow-in-the-dark watch and clock faces, is also known to cause cancer.

Additional World Book articles:

• Alkaline earth metal
• Earthquake
• Nuclear energy
• Tsunami
• Japan 2011 (a Back in Time article)
• Reconsidering Nuclear Power (a special report)

December 7, 2012

A 7.3-magnitude earthquake centered off northeastern Japan shook buildings as far away as Tokyo, the capital, and triggered a small 3-foot (1-meter) tsunami. The tsunami occured in the same area that was devastated in March 2011 by a massive earthquake, tsunami, and nuclear disaster. There were, however, no reports of deaths or serious damage in today’s quake.

The March 2011 earthquake and subsequent tsunami left nearly 20,000 people dead and resulted in a series of meltdowns at the Fukushima-Daiichi nuclear power plant, leaking radiation into the sea and air and contaminating the land. Much of the area is still a deserted wasteland.

A huge wave strikes Japan's coast on March 11, 2011. An earthquake that day caused a tsunami (series of powerful ocean waves) that caused widespread destruction on Honshu, Japan's largest island. (© Mainichi Shimbun, Reuters)

Additional World Book articles:

• Fallout
• Big waves: Tracking Deadly Tsunamis (a special report)
• When the Earth Moves ( a special report)
• Japan 1923 (a Back in Time article)
• Japan 2011 (a Back in Time article)

April 11, 2012

Indonesia’s Aceh province was shaken this morning by two major earthquakes–one with a magnitude of 8.6, the other measuring 8.3. The earthquakes were centered below the Indian Ocean at a depth of 20 miles (33 kilometers), some 300 miles (495 kilometers) off the coast of Banda Aceh, the provincial capital. Fearing a tsunami like the disastrous one in 2004, the Pacific Tsunami Warning Center issued a tsunami warning. The warning was cancelled after no massive waves developed from the quake. The Indian Ocean tsunami of 2004 killed some 250,000 people in coastal areas of Southeast Asia, South Asia, and East Africa.

An earthquake under the ocean may cause a tsunami, a series of ocean waves that can cause tremendous destruction along coastlines. (World Book illustration by Matt Carrington)

Indonesia is regularly struck by earthquakes. The country’s island of Sumatra is close to an active subduction zone, where the Indian-Australian tectonic plate presses into and under the Eurasian plate. The collision of the plates has created a huge depression on the ocean floor known as the Sunda Trench. Strain between the plates at this depression is eventually released in the form of an earthquake.

Additional World Book articles

• Big Waves: Tracking Deadly Tsunamis (a special report)
• When the Earth Moves (a special report)
• Indonesia 2004 (Back in Time article)
• Indonesia 2005 (Back in Time article)

March 28, 2012

Damage to one of the reactors at Japan’s crippled Fukushima Daiichi nuclear power plant is much worse than previously thought, Tokyo Electric Power Co. announced today. On March 27, workers were able to insert a probe into reactor #2. Radiation was found to be 10 times as great as a fatal dose, the highest level yet recorded at the plant. The probe also revealed that cooling water in the reactor vessel was only 24 inches (60 centimeters) from the bottom, far below the level estimated when the government declared the plant stable in December. The instrument used to assess damage inside the reactor chamber was equipped with a tiny video camera, a thermometer, a water gauge, and a dosimeter (a small device for measuring the doses of atomic radiation).

The Fukushima Daiichi plant was severely damaged on March 9, 2011, by one of the worst natural disaster in Japanese history–a magnitude 9 earthquake off Honshu, Japan’s main island. The earthquake, in turn, triggered a massive tsunami that resulted in the deaths of thousands of people.

Nuclear energy experts suggest that the other two reactors at Fukushima that underwent meltdowns could be in even more serious states. Because of extreme radiation levels, neither has been examined closely. Before the disaster, the Fukushima plant generated one-third of Japan’s electric power.

Public reaction to the meltdown at Fukushima has persuaded the Japanese government to shut down all but 1 of the nation’s 54 nuclear reactors in operation before the disaster. The last is to be switched off in May.

Additional World Book articles

• Energy supply
• Japan earthquake and tsunami of 2011
• Three Mile Island
• Japan 1923 (Back in Time article)
• Japan 2011 (Back in Time article)
• Big Waves: Tracking Deadly Tsunamis (a special report)
• When the Earth Moves (a special report)

Dec. 16, 2011

The crippled nuclear reactors at the Fukushima Daiichi power plant have been stabilized, declared Japanese Prime Minister Yoshihiko Noda in a televised address to the nation. The magnitude-9 earthquake and subsequent tsunami that hit Japan’s main island, Honshu, on March 11 knocked out cooling systems, triggering blasts at four of the plant’s six reactors. Using seawater, workers at the plant have cooled the reactors to “cold shutdown” level, meaning the water that cools the nuclear fuel rods remains below the boiling point.

The core is the heart of a nuclear reactor. Nuclear fuel in the core of this boiling water reactor produces heat that converts water to steam. The steam runs machinery outside the reactor. A pressure vessel encloses the core and various other equipment. General Electric (World Book diagram)

For many, however, the crisis is hardly over. More than 160,000 people had to leave the area, and radiation levels in some places remain too high for people to return. A 12-mile (20-kilometer) exclusion zone remains in effect around the plant. Tokyo Electric Power Company, which operates Fukushima, acknowledges that the uranium fuel in three reactors has probably melted through their containments (holding tanks). Some nuclear experts suggest that the fuel is probably threatening ground water. The Japanese government announced earlier this week that it could take up to 40 years to fully decommission the plant and clean up surrounding areas.

The Fukushima Daiichi disaster was the world’s worst nuclear crisis since Chernobyl. The Chernobyl nuclear power plant disaster took place in Ukraine in 1986.

Dec, 5, 2011

The tsunami that ravaged Japan in March 2011 was powered by earthquake that shifted the seafloor more than 100 times farther than previous quakes in the region. The 9.0-magnitude earthquake was the strongest to hit Japan in more than 130 years. At least 15,800 people died in the resulting tsunami. The disaster also triggered at least one meltdown of a reactor core at a nuclear power plant.

New measurements made off the coast of Honshu, Japan’s main island, have revealed that the quake thrust the seafloor upward by 33 feet (10 meters) and pushed it horizontally 164 feet (50 meters) toward the island. The measurements were made by scientists from the Japan Agency for Marine-Earth Science and Technology using devices that direct sound waves at the seafloor. The returning echoes enabled the scientists to create a map of the area, which they compared with maps made in 1999 and 2004. The violent movement of the seafloor caused the column of water above it to explode upward, setting off waves that traveled outward in all directions. The waves, which built up as they entered shallow water along the coastline, reached heights of at least 30 feet (9 meters). The 2011 quake occured along the border between two of the tectonic plates that make up Earth’s outer shell.

A tsunami can occur when an underwater earthquake displaces a large part of the sea floor. In this illustration, a tsunami wave spreads from a fast-rising section of ocean floor. The rising plate lifts the water above it, raising a hump of water that quickly ripples outward. As the ripple enters shallow water, it slows and grows in height. World Book illustration by Matt Carrington.

Additional World Book articles:

• Japan earthquake and tsunami of 2011
• Richter magnitude
• Tsunami of 2004