Mar-12: The Wonders of Science and Man Made Disasters

March 12th demonstrates what happens when scientific achievement, mother nature and hubris collide.

1928

St. Francis Dam Collapse

The St. Francis Dam was a curved concrete gravity dam, built to create a large regulating and storage reservoir for the City of Los Angeles, California. The reservoir was an integral part of the city’s Los Angeles Aqueduct water supply infrastructure. It was located in San Francisquito Canyon of the Sierra Pelona Mountains, about 40 miles (64 km) northwest of Downtown Los Angeles, and approximately 10 miles (16 km) north of the present day city of Santa Clarita.

The dam was designed and built between 1924 and 1926 by the Los Angeles Department of Water and Power, then named the Bureau of Water Works and Supply. The department was under the direction of its General Manager and Chief Engineer, William Mulholland.

At two and a half minutes before midnight on March 12, 1928, the dam catastrophically failed, and the resulting flood took the lives of as many as 600 people.The collapse of the St. Francis Dam is considered to be one of the worst American civil engineering disasters of the 20th century and remains the second-greatest loss of life in California’s history, after the 1906 San Francisco Earthquake and fire. The disaster marked the end of Mulholland’s career.

From the Los Angeles Times

Mulholland’s distinguished career was over. He resigned seven months later at age 72, depressed and ill from Parkinson’s disease, and died sad and broken in 1935. New inquiries in the 1990s shifted the blame for the St. Francis to an ancient landslide, undetectable even by the most accomplished geologists of the 1920s.

 

2011

Fukushima Meltdown

The Fukushima Daiichi Nuclear Power Plant sits 288.1 km north of Tokyo and suffered major damage following a magnitude 9.0 earthquake and tsunami that hit Japan on March 11, 2011.

Part 1:  The Earthquake

From Popular Mechanics:

A powerful earthquake caused a massive tsunami that crashed into Fukushima Daiichi Nuclear Power Plant and caused multiple nuclear reactor meltdowns. . . . At the site of the earthquake, stress had been building up in the Earth’s crust for decades. When it released, that stress caused one of the most damaging quakes on record. The earth moved more than 20 meters over a 500-mile zone and the resulting earthquake released as much energy as a 45-megaton hydrogen bomb (to put this in perspective, this is 30,000 times more powerful as the bomb that leveled Hiroshima). It was the fourth-strongest earthquake recorded since 1900 and the strongest earthquake to strike Japan in recorded history. The quake shifted the Earth’s axis by somewhere between 4 and 10 inches, altering the length of a day by nearly 2 microseconds.

Part 1:  The Tsunami

While the reactors automatically shut down due to the earthquake, the tsunami disabled emergency generators needed to power the pumps needed to cool the reactor.

From Wikipedia:

The insufficient cooling led to three nuclear meltdowns, hydrogen-air explosions, and the release of radioactive material in Units 1, 2, and 3 from 12 March to 15 March. Loss of cooling also caused the pool for storing spent fuel from Reactor 4 to overheat on 15 March due to the decay heat from the fuel rods.

. . . .The Fukushima disaster was the most significant nuclear incident since the April 26, 1986 Chernobyl disaster and the second disaster to be given the Level 7 event classification of the International Nuclear Event Scale. Though there have been no fatalities linked to radiation due to the accident, the eventual number of cancer deaths, according to the linear no-threshold theory of radiation safety, that will be caused by the accident is expected to be around 130–640 people in the years and decades ahead

 

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