NEPAL QUAKE (Gorkha earthquake)
Major Quake Hits Nepal
A little before noon Saturday in Nepal, a chunk of rock about 9 miles below the earth’s surface shifted, unleashing a shock wave—described as being as powerful as the explosion of more than 20 thermonuclear weapons—that ripped through the Katmandu Valley.
In geological terms, the tremor occurred like clockwork, 81 years after the region’s last earthquake of such a magnitude, in 1934.
Records dating to 1255 indicate the region—known as the Indus-Yarlung suture zone—experiences a magnitude-8 earthquake approximately every 75 years, according to a report by Nepal’s National Society for Earthquake Technology.
The reason is the regular movement of the fault line that runs along Nepal’s southern border, where the Indian subcontinent collided with the Eurasia plate 40 million to 50 million years ago.
As the plates push against each other, friction generates stress and energy that builds until the crust ruptures, said Dr. Chan, who compared the quake to a thermonuclear weapons explosion. In the case of Saturday’s quake, the plate jumped forward about 2 meters, or 6.5 feet, said Hongfeng Yang, an earthquake expert at the Chinese University of Hong Kong.
Saturday’s quake was also relatively shallow, according to the U.S. Geological Survey. Such quakes tend to cause more damage and more aftershocks than those that occur deeper below the earth’s surface.
After an earthquake, the plates resume moving and the clock resets. “Earthquakes dissipate energy, like lifting the lid off a pot of boiling water,” said Dr. Chan. “But it builds back up after you put the lid back on.”
Nepal is prone to destructive earthquakes, not only because of the massive forces involved in the tectonic collision, but also because of the type of fault line the country sits on. Normal faults create space when the ground cracks and separates. Nepal lies on a so-called thrust fault, where one tectonic plate forces itself on top of another.
The most visible result of this is the Himalayan mountain range. The fault runs along the 1,400-mile range, and the constant collision of the India and Eurasia plates pushes up the height of the peaks by about a centimeter each year.
Despite the seeming regularity of severe earthquakes in Nepal, it isn’t possible to predict when one will happen. Historic records and modern measurements of tectonic plate movement show that if the pressure builds in the region in a way that is “generally consistent and homogenous,” the region should expect a severe earthquake every four to five decades, Dr. Yang said.
The complexity of the forces applying pressure at the fault means scientists are incapable of predicting more than an average number of earthquakes that a region will experience in a century, experts say.
Still, earthquakes in Nepal are more predictable than most, because of the regular movement of the plates. Scientists aren’t sure why this is.
The earth’s tectonics plates are constantly in motion. Some faults release built-up stress in the form of earthquakes. Others release that energy quietly. “Some areas, like Nepal, release energy as a large earthquake, once in a while,” said Dr. Chan. “These regions all have different natures for reasons geologists don’t really know.”
THE SCIENCE OF EARTHQUAKES
The April 25 quake measured 7.8 on the moment magnitude scale, the largest since the 1934 Bihar quake, which measured 8.2 and killed around 10,000 people. Another quake in Kashmir in 2005, measuring 7.6, killed around 80,000 people.
These quakes are a dramatic manifestation of the ongoing convergence between the Indo-Australian and Asian tectonic plates that has progressively built the Himalayas over the last 50 million years.
They are but one reminder of the hazards faced by the communities that live in these mountains.
Earthquakes occur when strain builds up in Earth’s crust until it gives way, usually along old fault lines. In this case the strain is built by the collision or convergence of two plates.
There are a number of factors made this quake a recipe for catastrophe.
It was shallow: an estimated 15km below the surface at the quake’s epicentre.
It saw a large movement of the earth (a maximum of 3m).
And the ruptured part of the fault plane extended under a densely populated area in Kathmandu.
From the preliminary analysis of the seismic records we already know that the rupture initiated in an area about 70km north west of Kathmandu, with slip on a shallow dipping fault that gets deeper as you move further north.
Over about a minute, the rupture propagated east by some 130km and south by around 60km, breaking a fault segment some 15,000 square kilometres in area, with as much as 3m slip in places.
The plates across this segment of the Himalaya are converging at a rate of about 2cm this year. This slip released the equivalent of about a century of built up strain.
The earthquake killed more than 7,500 and injured more than twice as many, as of 1 May 2015, Nepal's Prime Minister, Sushil Koirala, has said that the number could reach 10,000. The rural death toll may have been lower than it could have been as villagers were outdoors working when the quake hit.
The Himalayan Times reported that as many as 20,000 foreign nationals may have been visiting Nepal at the time of the earthquake, although reports of foreign deaths were relatively low. Hundreds of people are still considered missing and more than 450,000 are displaced.
A total of 78 deaths were reported in India - 58 in Bihar, 16 in Uttar Pradesh, 3 in West Bengal and 1 in Rajasthan.
People's Republic of China:
25 dead and 4 missing, all from Tibet.
Kathmandu: Bad weather has cut links with a remote village in Nepal where dozens of villagers and trekkers are believed to be buried under an avalanche set off by last month’s devastating earthquake, officials said on Tuesday.
The government said that more than 131,500 Nepalese military and police personnel were now taking part in the massive aid operation in the vast Himalayan nation, aided by more than 100 teams of foreign relief workers.
While the government has acknowledged being overwhelmed by the April 25 disaster and there have been complaints of delays to the relief effort, the home ministry indicated the situation was being brought under control.The National Emergency Operation Centre said the total number of dead had now reached 7,557 while 14,536 were injured in the 7.8-magnitude quake, Nepal’s deadliest in more than 80 years.
About 100 bodies were recovered on Saturday and Sunday at Langtang village, 60km (37 miles) north of Kathmandu, which is on a trekking route popular with Westerners. The entire village, which includes 55 guesthouses for trekkers, was wiped out by the avalanche and rescuers are digging in the snow for signs of about 120 others believed buried.
The government has begun asking foreign teams to wrap up search and rescue operations as hopes of finding people alive in the rubble receded.
A European Union source said only about 60 citizens from the 28-nation bloc were still unaccounted for. Last week a senior EU official had estimated around 1,000 EU citizens were missing after the quake.
The number is “going down by the hour” as rescue teams reach remoter areas, the EU source said.
A US State Department spokesman said helicopters chartered by the embassy in Kathmandu had rescued 17 US citizens in total from remote areas hit by the quake. The United States has provided $14.2 million in humanitarian aid since the quake.
The government has said it has not closed Mount Everest, the world’s highest peak, to climbers, although the route to the summit has been damaged by the earthquake. At least 18 people were killed on Everest when the earthquake struck.The United Nations has said 8 million of Nepal’s 28 million people were affected by the quake, with at least 2 million needing tents, water, food and medicines over the next three months.
The United Nations Children’s Fund said more than half a million children were being vaccinated to prevent measles outbreaks. Around 1.7 million children remain in urgent need of humanitarian aid in the worst-hit areas.
Mount Everest Shrank As Nepal Quake Lifted Kathmandu
One inch, that’s how much Mount Everest, the world’s highest mountain, has shrunk by following the massive earthquake that hit Nepal on April 25. Satellite data from the European Space Agency showed that the mountain subsided, making it about an inch shorter than it was before. The lowering occurred due to a relief of strain in the Earth’s crust.
The devastating quake of April 25, which displaced millions, has led to major topographical changes.
Researchers spotted the changes, including the rise of Nepal’s capital city of Kathmandu by approximately 3ft. The shift was detected by comparing before-and-after radar images using a technique that produces an image called an interferogram. “The altitude of the Kathmandu Valley increased by 80cm as the Indian tectonic plate moved further to the Tibetan plate during the quake,” Madhu Sudan Adhikari, director general of the survey department said on Thursday, according to reports by Xinhua News Agency. In addition to the vertical lift, researchers also found horizontal shifts of up to 7 feet. The satellite data has also been used to help direct relief efforts in areas that have suffered from landslides.
increasing difficulties and challenges
rescue teams battling to save lives
The relief operation has been troubled by bureaucratic bottlenecks, logistic difficulties and rough terrain. Aftershocks are also continuing, though bad weather that had grounded helicopters has cleared.
Police, soldiers and volunteers have launched a major search operation in the remote Langtang region of the Nepalese Himalayas to look for up to 600 trekkers and support staff who have been missing since an 7.8-magnitude earthquake hit the south Asian country nine days ago.
After the disaster, devastation assaults all of the rescue team's senses. The sights of collapsed buildings, of bodies and gore; the sounds of crying out in pain, or the distant crack of gunfire; the acrid smell of rotting vegetation or the indescribable scent of decomposing bodies; the taste of our own sweat as we exhaust ourselves trying to make a difference; and the feel of the elements, such as pouring rain or unyielding heat, urging them to give up and go home.
In the face of trying to assist people in such dire circumstances, too often, relief workers ignore their own body signals suggesting that we need to rest, to eat, to hydrate.
Up to 30% of aid workers returning home may experience anxiety symptoms so severe that they meet criteria for a diagnosis of Post-Traumatic Stress Disorder, a condition requiring professional mental health assistance to manage.
no time to lose - Global response gears up
The official death toll from Saturday's earthquake rose to 2,352 people, Nepal's Interior Ministry confirmed on Sunday, while Prime Minister Sushil Koirala called for strong international support. Koirala's cry for help was met with strong support
A team of 45 rescue experts from Belgium, Germany and Luxembourg left on a Belgian military plane on Sunday, bound for Nepal.
Japan's emergency services team, comprised of 70 experts, were also dispatched on Sunday. Sri Lanka sent a military C-130 aircraft carrying a 48-member medical and relief team with essential supplies. A second plane was also expected to carry more medical staff.
Rescue workers continue to search for bodies after buildings collapses in the wake of Saturday's earthquake
India, China, and Pakistan were the first to respond following news of the disaster. India deployed two military transport panes, while Pakistan sent two C-130 aircrafts carrying food and essential supplies, including a 30-bed hospital. A 62-member Chinese search and rescue team was also dispatched to Katmandu on Saturday.
The US committed $1 million along with rescue teams, the US Agency for International Development confirmed. Australia and New Zealand pledged more than $4.5 million, while South Korea promised $1 million in humanitarian aid.
Numerous aid groups launched appeals for funds with the charity Christian Aid describing an "urgent need" for emergency shelters, food, clean drinking water, and warm clothing.
What measures should be taken by the people if caught in an earthquake of large magnitude?
caught in an earthquake?? stay calm
-If you're indoors, stay there ,stand against an interior wall. Stay clear of exterior walls, glass, heavy furniture, fireplaces and appliances. The kitchen is a particularly dangerous spot. If you’re in an office building, stay away from windows and outside walls and do not use the elevator.
-If you're outside, get into the open. Stay clear of buildings, power lines or anything else that could fall on you.
-If you're driving, move the car out of traffic and stop. Avoid parking under or on bridges or overpasses. Try to get clear of trees, light posts, signs and power lines. When you resume driving, watch out for road hazards.
-If you're in a mountainous area, beware of the potential for landslides. Likewise, if you're near the ocean, be aware that tsunamis are associated with large earthquakes. Get to high ground. Don’t even think about going to watch tsunamis!!
-If you’re in a crowded public place, avoid panicking and do not rush for the exit. Stay low and cover your head and neck with your hands and arms.
Get an emergency kit
Make sure your kit is easy to carry. Keep it in a backpack, duffel bag or suitcase with wheels, in an easy-to-reach, accessible place.
Basic emergency kit
- Water – at least two litres of water per person per day. Include small bottles that can be carried easily in case of an evacuation order
- Food that won't spoil, such as canned food, energy bars and dried foods (remember to replace the food and water once a year)
- Manual can opener
- Wind-up or battery-powered flashlight (and extra batteries)
- Wind-up or battery-powered radio (and extra batteries)
- First aid kit
- Special items such as prescription medications, infant formula and equipment for people with disabilities
- Extra keys to your car and house
After an Earthquake
-Check for fire or fire hazards. If you smell gas, shut off the main gas valve. If there's evidence of damage to electrical wiring, shut off the power at the control box.
-If the phone is working, only use it in case of emergency. Likewise, avoid driving if possible to keep the streets clear for emergency vehicles.
-Be aware that items may fall out of cupboards or closets when the door is opened, and also that chimneys can be weakened and fall with a touch. Check for cracks and damage to the roof and foundation of your home.
-Listen to the radio for important information and instructions. Remember that aftershocks, sometimes large enough to cause damage in their own right, generally follow large quakes.
-If you leave home, leave a message telling friends and family your location.