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The 11th March 2011 great mega-thrust Japan Earthquake (Mw 9.0)

A tsunamigenic mega-thrust earthquake of magnitude Mw 8.9 rocked the east coast of Honshu (38.32N; 142.37E), Japan on 11th March, 2011 at 05:46:23.7 UTC at a depth of about 24.5 km beneath the ocean (USGS). The earthquake was located about 130 km east of the Sendai and about 430 km northeast of Tokyo (USGS, IRIS). The earthquake was so powerful that a killer tsunamis wave generated at a height of about 30 – 35 ft, which caused a huge devastation in the entire coastal belts of Miyagi, Fukusima and Sendai city of Northeast Japan. This is the greatest earthquake so far recorded in the history of Japan seismology. Maximum damage was reported by several agencies of Japan and overseas to show the damage in the coastal belt of NE Japan was mainly due to tsunamis and the subsequent fire that broke out due to strong shaking and tsunamis. There is a report on nuclear emission and leakage after the mega-thrust earthquake. This earthquake was associated with tremendously high seismic moment that was capable to displace the original location of the northeast part of the Honshu Island.

It is worth to mention that the occurrence of such great devastating earthquakes is confined to the Forearc region of Northeast (NE) Japan for which a detailed 3-D seismic tomography outside the seismic network, for the first time, has already been assimilated from the Pacific coast to the Japan Trench using a large number of high-quality arrival times from sub-oceanic earthquakes that were well relocated with sP-depth phase data, a novel technique by a scientist of Geological Survey of India under his research endeavour in Japan that led to an ward of Doctor of Science (D.Sc.) to Dr. O. P. Mishra from the Geodynamics Research Centre, Ehime University, Japan, which is evident from the outstanding publications by Mishra et al. (2003) and Mishra and Zhao (2004). This detailed study on NE Japan forearc region demonstrated why and how the great mega-thrust tsunamigenic, and other past non-tsunamigenic earthquakes occur beneath the ocean. The study demarcated several high velocity zones and zones between low and high-velocity anomalies in the NE Japan Forearc, suggesting probable locations for great megathrust earthquakes of magnitude greater than 7.0 beneath the forearc (Mishra et al., 2003). The region has already been associated with several past damaging interplate earthquakes having heterogeneous rupture dimensions that overlap one after another (Nagai et al., 2001; Mishra et al., 2003). The study revealed that varying degree of interplate seismic coupling; strong heterogeneities; dehydration embrittlement, and continuous weakening of the subducting Pacific Sea slab due to its serpentinization are the plausible cause of occurrence of such great devastating mega-thrust earthquakes in past (Mishra et al., 2003; Mishra and Zhao, 2004) as well the cause of the greatest mega-thrust earthquake (Mw 8.9) that rocked the NE Japan forearc on the 11th March 2011.



Head on Crash Leaves Nuclear Fuel Truck in Flames

On December 16, 1991, at about 3.15 am in Springfield, MA, USA, a drunken car driver entered the Interstate Lane 91 on wrong way. After traveling 4 km his car crashed head on into the truck trailer. Both vehicles careened off each other. Truck crashed into a concrete abutment and burst into flames shooting 2030 feet in air. Lane 91 and nearby lanes were closed.

After about 2 hours dwarfed flames were extinguished using dry chemicals. Consignment was allowed to cool. The area was monitored by Health physicist and cleaned. After ascertaining that there is no contamination lane was allowed to operate.



Candle Caused Nuclear Emergency

On March 22, 1975, at noon, the sealing of air leak was attempted using spongy foam rubber, in the cable spreading room situated below the control room of Unit 1 & 2 of Brown's Ferry Nuclear Power Plants, Albama, USA producing 2200 megawatts of electricity. As a routine practice the observation of candle flame movement was carried out In doing so, the candle was brought too close to .foam rubber. It burst into flames. The resulting fire disabled many safety systems including emergency core cooling system. It caused almost boil-off I meltdown. The fire knocked off radiation monitors, electric sequence printer, aircraft warning lights placed on 600 feet radioactive gas release stack. 50-75 employees gathered in control room having capacity to accommodate 6 persons causing chaos. Luckily, reactor water level, temperature and pressure indicators continued to function and both plants were safely shut down, otherwise it would have been a major accident. It demonstrated the vulnerability of nuclear power plants to 'single failure' and human fallibility.



The COSMOS 954 Accident

On 24 January 1978, COSMOS 954, a Soviet nuclear powered surveillance satellite crashed in Northwest Territories of Canada. The large amount of radioactivity was scattered over a 124,000 square kilometer. Canada and USA jointly carried out "Operation Morning Light" until October 1978. The exercise included aerial and ground reconnaissance and additionally working of decontamination team on foot. The estimated recovery was about 0.1 %. This lead to study nuclear-powered satellites by a special group under the aegis of United Nations.



The Three Mile Inland Accident

On March 28, 1979, a nuclear power plant, Three Mile Island (Harrisburg, Pennsylvania, USA), had a near meltdown (over heating of fuel rods and release of radioactivity). A malfunction in the secondary cooling circuit caused temperature rise in primary coolant. Following reactor closed automatically but relief valve failed to close. Also the instrumentation failed to reveal and primary coolant drained away.

The residual heat in the reactor was not removed and the core damaged severely. Fission products, namely nobel gases (1 %) and radioiodine (0.00003 %) were released into the environment. There were no injuries or adverse health effects. Pennsylvania Governor recommended that pregnant women leave the area, and tens of thousands tied the area on their own. 100 mrem was maximum dose to people living near by and average community dose was 1 mrem. A couple of days after the. accident the dose was non-significant above regular background. Immediate administration of potassium iodide (KI) was recommended to the nearby people but it was not available. The significant psychological sequelae occurred. Accident was rated at level 4 on the International Nuclear Event Scale (lNES).



The Windscale Accident

At Wind scale in UK, during routine servicing in 1957 some uranium and graphite caught fire in plutonium production unit. An estimated 20,000 ci of 1-131, were released to the environment. There was no evacuation but milk supply was contaminated and prohibited for 25 to 44 days. The accident is rated at level 4 of the INES. UK vetoed the details.



The Tokaimura Accident

On Sept. 30, 1999 at Uranium Conversion Facility in Tokaimura, Japan human error and departure from approved guide lines caused nuclear criticality / chain reaction. Radiations and radioactive materials were released in the environment. Three workers were over exposed to radiations and two of them died of acute radiation syndrome. 667, persons were exposed to radiations. However there was no report of adverse health effect and accident rated at level 4 on the INES.



The Chernobyl Accident

On 26th April 1986, the world's most severe nuclear accident, rated at level 7 on the INES had occurred at Chernobyl, USSR (now Ukraine). When operators tested the capability of the plant's electrical back-up system. At that time part of the plant was shut down for routine maintenance. There was no exchange of communication and coordination between the Testing Team and Team responsible for operation and safety.

In addition, the enormity of the accident was compounded by reactor design drawbacks. Soon the sudden and uncontrollable power surge was triggered, it resulted into violent explosion and almost destruction of the reactor. Graphite moderator burnt, building caught fire, prolonged wide spread of radioactive material in the environment occurred. About 120 million curies of radioactivity and about 6-7 tons of materials were released contaminating more than 210,000 square kilometer area of Ukraine, Belarus and Russian Federation. Within 2 hours and 45 minutes, 40,000 persons were evacuated from when radiation dose was about 1 rad/hr. As on 1.1.95145,000 km2 has more than 1 Ci/km2 on which 7 million people live. 800,000 people were involved in the accident, 116,000 persons were evacuated until mid August 1986 and additionally 52,000 in Ukraine, 106,00 in Belarus and 47,500 in Russian Federation were resettled. 237 persons were hospitalize due to over exposure and first degree burns. 134 persons were diagnosed for Acute Radiation Syndrome (ARS), 56 got radiation burn injuries including 2 with additional skin injuries. Of the 31 deaths, 28 persons died of over exposure, 2 persons due to explosion and 1 person due to prospective coronary thrombosis. 5 persons died between 1987 -90 and nine from 1992-96 due to ARS. A total of almost 17 million people, including 2.5 million younger than 5 years of age, were exposed to excess radiation. The delayed effect, beginning 4 years after exposure was a great excess of cases of thyroid cancers in children and adolescents especially those who were younger that 4 years at the time of accident. Allogenic bone marrow transplants (13) and liver cell from fetus transplants (6) were carried out. But many transplants were not successful except of two where the donor was very close relative. The massive decontamination exercise consisted aerial survey, monitoring food and disposal of contaminated food, removal of equipments, 5-10 cm soil layer, decontamination of buildings, laying concrete 'slabs and their coating, protection of river. The estimated excess cancers are 125,400 against 6.99.17 million normal cancers in Chernobyl, USSR, Europe and Northern Hemisphere where a total estimated population is 3568.135 million. The severe excess mental retardation may be 20 against spontaneous estimate of 13, showing 140 % increase. The severe genetic abnormality may be 100 against spontaneous estimate of 7000 indicating 1.5 % increase. The other estimate quotes in next 30 years there may be 0.12 - 0.40 million thyroid cancers (due to 1-131 inhalation but few percent fatal), 0.1 -0.25 million thyroid cancers (1-131 in milk) and 0.085 -0.70 million cancers due to Csl-'137 and half may be fatal.



Kyshtym Accident

The USA Congress brief of July 1, 1986 states that major accident had occurred at Kyshtym in Ural mountains (USSR), the first Soviet plutonium production site in 1957/1958. It claimed many lives and contamination of wide area dangerously. The accident involved significant release of radioactive material and likely involving lull implementation of countermeasures but less severe than a major accident like Chernobyl. The accident is rated at level 6 of the INES.



Wrong Estimate

"Castle/Bravo' was the largest nuclear weapon ever detonated by USA', on February 28, 1954 in Marshal Island, Bikini Atoll. Against expected yield of 8 MT of TNT it produced 15 MT power. The fallout consisted of coral rocks, soil and other debris sucked up in the fireball. It contaminated about 11,000 km2 of the Pacific Ocean. At about 6 hours fine sandy ash sprinkled over the Japanese fishing vessel lucky Dragon located at about 145 km downwind. At Rongelap Atoll 200 km in the down wind, the fall out reached after 7 hours. At one place the dose rate was 150 rads/hr and total dose in first 4 days was 2000 rads and at 450 km the dose was a 100 rads. Of the 32 Marshallese exposed to fallout before 20 years of age, 4 persons developed thyroid cancer and one person developed leukemia.



Radiation Accidents
  • Juarez, Mexico: In 1977 a cobalt radiotherapy machine having activity of 3000 Ci Go-60 manufactured by Picker Corporation was supplied to Centro Medico, Juarez. The Machine was not installed until 1983 and was stolen in December 1983. It was dismantled and found its way in scrap metal yard. The scrap reached to three steel foundries and was processed. Contaminated steel rods were detected by radiation sensors in the road outside the Los Alamos National Laboratory, New Mexico and the was revealed in January 1984. But by this time 5000 tons of the contaminated steel had been used in construction in Mexico and making restaurant table legs in St. Louis Missouri. The remaining steel was stopped from using. The truck was haevily contaminated but children played for a month. It is suspected that some radio cobalt became air and water born. Counter actions are pending and also difficult to contain the radioactivity.
  • On Sept" 13, 1987, in Goiania, Brazil, an abandoned radiotherapy. Machine having 1,400 Ci Cs-137 was looted and dismantled. Over the following two weeks, the children played and distributed the luminous blue CsCI. The daughter of the scrap vendor, reported that she had covered herself with CsCI powder and even eaten some of it. 4000 persons were monitored, 30 families evacuated, 20 persons were hospitalized. An .estimated 250 persons were exposed with some receiving dose more than 1000 rads. 4 persons including daughter of the scrap dealer died. Skin burns and acute radiation sicknesses were reported. 'Rradiogardase-Cs' (prussian blue) was administered for more than 150 days in the doses 1-20 9 daily under temporary clearance from FDA. Thousands of people rushed to emergency and 6000 tons of clothing, furniture, dirt and other


The Second World War

The atomic bomb explosion in Hiroshima and Nagasaki in Japan on 6 and 8 August 1945 remained the most defining evidences of the consequence of nuclear war. At Hiroshima the bomb exploded in air at 1670 feet height over Shima Hospital at 8.15 a.m. The estimated yield was equivalent to 15 kiloton of TNT. The 50 % energy was consumed in high pressure blast, 35 % in heat and remaining in radiations (5 % immediate nuclear radiations (INR) and 10 % delayed radiations due to fallout). Beneath the hypocenter or ground zero or explosion center the temperature was 7000° F and wind velocity was 980 miles/hr (- 1600 km/hr). Gray stones changed to whit and ceramic tiles of roof melted (0.33 miles), and the clothes which people wore burnt (1.25 miles). The wind velocity was 620 miles/hr at 0.33miles with pressure of 460.0 pounds per square feet resulting into destruction of most of the concrete buildings in the range. At 1 mile the wind velocity was 190 miles/hr and pressure of 1180 pounds per square feet resulting into destruction of all brick buildings. Most of the people who happened to be within 0.1 km radius died within few hours and those within half a mile in 30 days. Of the 255,000 exposed to bomb effects, 68,000 died and 76,000 injured. 67% deaths occurred in the first day, of which 50% burn deaths and 30 % due to radiations. In Nagasaki (height of burst 1640 ft), the bomb yield was 22 KT of TNT that killed 38,100 and injured 21,000 among the 195,000 persons exposed. The hilly terrain of Nagasaki shielded the bomb effects.

By the end of 1945, the death toll due to bombing of Hiroshima was 69,000 as a direct result. In absence of the statistical data it is estimated that cumulative deaths were 145,000 upto 1952, and subsequent collection of data by the Hiroshima City Government revealed total death of 200,000 persons as a direct result of the bombing upto 2000. Fortunately, no genetic damages have been noticed so far. The studies clearly showed that exposure to low radiation doses is also of great concern when health of human being is the consideration.



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