2015 Nepal Earthquake

The April 2015 Nepal earthquake (also known as the Gorkha earthquake) killed 8,962 people and injured 21,952 across the countries of Nepal, India, China and Bangladesh. It occurred at on Saturday 25 April 2015, with a magnitude of M_w 7.8–7.9 or M_s 8.1 and a maximum Mercalli Intensity of X (''Extreme''). Its epicenter was east of Gorkha District at Barpak, Gorkha, roughly northwest of central Kathmandu, and its hypocenter was at a depth of approximately . It was the worst natural disaster to strike Nepal since the 1934 Nepal–India earthquake. The ground motion recorded in Kathmandu, the capital of Nepal, was of low frequency, which, along with its occurrence at an hour when many people in rural areas were working outdoors, decreased the loss of human lives.

The earthquake triggered an avalanche on Mount Everest, killing 22 people, the deadliest incident on the mountain on record. The earthquake triggered another huge avalanche in the Langtang valley, where 250 people were reported missing.

Hundreds of thousands of Nepalese were made homeless with entire villages flattened across many districts of the country. Centuries-old buildings were destroyed at UNESCO World Heritage Sites in the Kathmandu Valley, including some at the Kathmandu Durbar Square, the Patan Durbar Square, the Bhaktapur Durbar Square, the Changu Narayan Temple, the Boudhanath stupa, and the Swayambhunath stupa. Geophysicists and other experts had warned for decades that Nepal was vulnerable to a deadly earthquake, particularly because of its geology, urbanization, and architecture. Dharahara, also called Bhimsen Tower, a nine-storey tall tower, was destroyed. It was a part of the architecture of Kathmandu recognized by UNESCO.

Continued aftershocks occurred throughout Nepal at intervals of 15–20 minutes, with one shock reaching a magnitude of 6.7 on 26 April at 12:54:08 NST. The country also had a continued risk of landslides.

A major aftershock occurred on 12 May 2015 at with a moment magnitude (M_w) of 7.3. The epicenter was near the Chinese border between the capital of Kathmandu and Mount Everest. More than 200 people were killed and over 2,500 were injured by this aftershock, and many were left homeless.

Earthquake

The earthquake occurred on 25 April 2015 at 11:56 am NST (06:11:25 UTC) at a depth of approximately (which is considered shallow and therefore more damaging than quakes that originate deeper in the ground), with its epicentre approximately southeast of Lamjung, Nepal, lasting approximately 50 seconds. The earthquake was initially reported as 7.5 by the United States Geological Survey (USGS) before it was quickly upgraded to 7.8, while the Global Centroid Moment Tensor (GCMT) reported a magnitude of 7.9. The China Earthquake Networks Center (CENC) reported the earthquake's magnitude to be 8.1 . The India Meteorological Department (IMD) said two powerful quakes were registered in Nepal at 06:11 UTC and 06:45 UTC. The first quake had its epicenter was identified at a distance of 80 km to the northwest of Kathmandu, the capital of Nepal. Bharatpur was the nearest major city to the main earthquake, as the crow flies from the epicenter. The second earthquake was somewhat less powerful at 6.6 . It occurred east of Kathmandu and its seismic focus lay at a depth of below the earth's surface. Over 38 aftershocks of magnitude 4.5 or greater occurred in the day following the initial earthquake, including one of 6.8 .

According to the USGS, the earthquake was caused by a sudden thrust, a short sharp thrust that caught many unsuspected and dies to this thrust only, along the major fault line where the Indian plate, carrying India, is slowly diving underneath the Eurasian plate, carrying much of Europe and Asia. Kathmandu, situated on a block of crust approximately 120 km (74 miles) wide and 60 km (37 miles) long, rapidly shifted 3 m (10 ft) to the south in a matter of just 30 seconds.

The risk of a large earthquake was well known beforehand. In 2013, in an interview with seismologist Vinod Kumar Gaur, ''The Hindu'' quoted him as saying, "Calculations show that there is sufficient accumulated energy n the Main Frontal Thrust">Main_Frontal_Thrust.html" ;"title="n the Main Frontal Thrust">n the Main Frontal Thrust now to produce an 8-magnitude earthquake. I cannot say when. It may not happen tomorrow, but it could possibly happen sometime this century, or wait longer to produce a much larger one." According to Brian Tucker, founder of a nonprofit organization devoted to reducing casualties from natural disasters, some government officials had expressed confidence that such an earthquake would not occur again. Tucker recounted a conversation he had with a government official in the 1990s who said, "We don't have to worry about earthquakes anymore, because we already had an earthquake." The previous earthquake to which he referred occurred in 1934. In fact, the 600-km-long Central Himalayan Gap hadn't ruptured 1505 Lo Mustang earthquake">since 1505.

Geology

Nepal lies towards the southern limit of the diffuse continental collision">collisional boundary where the Indian plate underthrusts the Eurasian plate, occupying the central sector of the Himalayan arc, nearly one-third of the long Himalayas. Geologically, the Nepal Himalayas are subdivided into five tectonic zones from north to south, east to west, and almost parallel to sub-parallel. These five distinct morpho-geotectonic zones are: (1) Terai Plain; (2) Sub Himalaya (Siwalik Hills, Shivalik Range); (3) Lesser Himalaya (Mahabharat Range and mid valleys); (4) Higher Himalaya; and (5) Inner Himalaya (Tibetan Tethys). Each of these zones is clearly identified by its morphological, geological, and tectonic features.

The convergence rate between the plates in central Nepal is about per year. The location, magnitude, and focal mechanism of the earthquake suggest that it was caused by a slip along the Main Frontal Thrust.

The earthquake's effects were amplified in Kathmandu as it sits on the Kathmandu Basin, which contains up to of sedimentary rocks, representing the infilling of a lake.

Based on a study published in 2014, of the Main Frontal Thrust, on average a great earthquake occurs every 750 ± 140 and 870 ± 350 years in the east Nepal region. A study from 2015 found a 700-year delay between earthquakes in the region. The study also suggests that because of tectonic stress buildup, the 1934 earthquake and the 2015 quake are connected, following a historic earthquake pattern. A 2016 study on historical great (M ≥ 8) earthquake pairs and cycles found that associated great earthquakes are likely to occur in the West China region through the 2020s.

Intensity

According to the USGS website, the maximum intensity was VIII (''Severe''), however certain reports state an intensity of X (''Extreme'') or higher. In most of Kathmandu the intensity was VIII-IX, as evidenced by the numerous undamaged water towers installed on top of undamaged multi story buildings. Tremors were felt in the neighboring Indian states of Bihar, Uttar Pradesh, Assam, West Bengal, Odisha, Sikkim, Jharkhand, Uttarakhand, Gujarat, in the National Capital Region around New Delhi and as far south as Karnataka. Damage was extensive in northern Bihar and minor damage was also reported from parts of Odisha. Shaking was felt in high-rise buildings as far as Kochi in the southern state of Kerala. The intensity in Patna was V (''Moderate''). The intensity was IV (''Light'') in Dhaka, Bangladesh. The earthquake was also experienced across southwest China, ranging from the Tibet Autonomous Region to Chengdu, which is away from the epicenter. Tremors were felt in Pakistan and Bhutan.

Aftershocks

A series of aftershocks began immediately after the mainshock, at intervals of 15–30 minutes, with one aftershock reaching 6.6M_w within 34 minutes of the initial quake. A major aftershock of magnitude 6.9 M_w occurred on 26 April 2015 in the same region at 12:54 NST (07:08 UTC), with an epicenter located about south of Kodari, Nepal. The aftershock caused fresh avalanches on Mount Everest and was felt in many places in northern India including Kolkata, Siliguri, Jalpaiguri, and Assam. The aftershock caused a landslide on the Koshi Highway, which blocked the section of the road between Bhedetar and Mulghat.

A model of GeoGateway, based on a United States Geological Survey mechanism of a near-horizontal fault as well as the location of aftershocks showed that the fault had an 11° dip towards the north, striking at 295°, was wide, long, and had a dip slip of . The USGS says the aftershock registered at a shallow depth of .

As of 24 May 2016, 459 aftershocks had occurred with different epicenters and magnitudes equal to or above 4 M_w (out of which 51 aftershocks are equal to or above 5 M_w and 5 aftershocks above 6 M_w) and more than 20,000 aftershocks less than 4 M_w.

12 May 2015 earthquake

A second major earthquake occurred on 12 May 2015 at 12:50 NST with a moment magnitude (M_w) of 7.3M_w 18 km (11 mi) southeast of Kodari. The epicenter was near the Chinese border between the capital city of Kathmandu and Mount Everest. It struck at a depth of 18.5 km (11.5 miles). This earthquake occurred along the same fault as the original magnitude 7.8 earthquake of 25 April but further to the east. As such, it is considered an aftershock of the 25 April quake. Tremors were also felt in northern parts of India including Bihar, Uttar Pradesh, West Bengal and other North-Indian States. At least 153 people died in Nepal as a result of the aftershock and about 2,500 were injured. 62 others died in India, two in Bangladesh, and one in China.

Aftermath

Disastrous events in very poor and politically paralyzed nations such as Nepal often become a long drawn out chain of events, in that one disaster feeds into another for years or even decades on end. The aftereffects of the earthquake had subsequent effects on a myriad of things: human trafficking, labour cost and availability, rental and property cost burdens, urbanization, private and public debt burdens, mental health, politics, tourism, disease, and damage to the healthcare system. A surve
some 30 months later
found only 12% of the reconstruction money had been distributed, and those without land were locked out of financial support, exacerbating the social divide and feeding marginalization.

More direct effects

Some disasters that came with the monsoon season were suspected to be related to the earthquake. There was a landslip on 11 June, killing 53 people. Meanwhile, a glacial lake had burst in the particularly hard-hit Solukhumbhu district. Whether or not the quake contributed to such events is often unknown and unresearched, but it is certainly possible.

Casualties

Nepal

The earthquake killed at least 8,857 people in Nepal and injured nearly three times as many. The rural death toll may have been minimized by the fact that most villagers were outdoors working when the quake hit. As of 15 May, 6,271 people, including 1,700 from the 12 May aftershock, were still receiving treatment for their injuries. Nearly 3.5 million people were left homeless, causing around 2.6 million internal displacements.

The example of this earthquake shows that loss calculations for hypothetical likely future earthquakes can be reasonably reliable. In 2005, the expected numbers of fatalities due to a hypothetical scenario earthquake near Kathmandu for M8.1 was published. The fatalities at that time were estimated between 21,000 and 42,000. The M7.8 earthquake of 25 April 2015 killed about 8,800 people because it occurred on a Saturday and so many buildings that collapsed, such as schools and municipal buildings, were empty, reducing the death toll. In addition, the epicentre of the earthquake was in a rural setting, so the worst hit districts had low population densities and most of the population was outside when the earthquake hit. Had the earthquake occurred at night or during the working week, when many more people were inside vulnerable buildings, the death toll would have likely been much closer to the modelled estimate.

After the rupture area of the Kathmandu 2015 earthquake had been derived and the intensities of shaking had been mapped, a line source model for losses could be constructed with energy being radiated along the entire rupture. The fatalities estimated in this way by QLARM agree with those reported in the end. The figure shows reports of fatalities as a function of time. News reports significantly underestimated the actual numbers of fatalities for several days.

''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.

India

A total of 78 deaths were reported in India – including 58 in Bihar, 16 in Uttar Pradesh, 3 in West Bengal and 1 in Rajasthan.

China

Twenty-seven people were confirmed dead, 383 were injured and 4 were missing, all from the Tibet Autonomous Region.
The quake destroyed 2,500 houses and damaged 24,700 others across 19 counties in Tibet, affecting nearly 300,000 people, among whom 47,500 were displaced, while A total of 82 temples were also damaged. The counties of Gyirong, Nyalam and Tingri in Xigazê were worst hit, where nearly 80 percent of the houses in the three counties collapsed.

Bangladesh

Four people were killed and 18 districts were affected by the earthquake in Bangladesh. A six-story building partially collapsed and two garment factories tilted in Dhaka. A 22-year-old man died when trying to flee the Dhaka Medical College in a panic. In Tangail, a woman died trying to escape a building. Another woman was crushed to death by a collapsed wall while a teacher died of a heart attack during the earthquake.

Avalanches on Mount Everest

This earthquake caused avalanches on Mount Everest. At least 19 died, with at least 120 others injured or missing.

Landslides in the Langtang Valley

In the Langtang valley located in Langtang National Park, 329 people were reported missing after an avalanche hit the village of Ghodatabela and the village of Langtang. The avalanche was estimated to have been two to three kilometres wide. Ghodatabela was an area popular on the Langtang trekking route. The village of Langtang was destroyed by the avalanche. Smaller settlements on the outskirts of Langtang were buried during the earthquake, such as Chyamki, Thangsyap, and Mundu. Twelve locals and two foreigners were believed to have survived. Smaller landslides occurred in the Trishuli River Valley with reports of significant damage at Mailung, Simle, and Archale. On 4 May it was announced that 52 bodies had been found in the Langtang area, of which seven were of foreigners.

According to geological models, the frequency and intensity of future landslides in the Langtang Valley is due to increase in the coming decades. This is attributable directly to the effect of the earthquake, which caused widespread fracturing in the grounds of the Langtang area.

Damage

Thousands of houses were destroyed across many districts of the country, with entire villages flattened, especially those near the epicenter.

The Tribhuvan International Airport serving Kathmandu was closed immediately after the earthquake, but was re-opened later in the day for relief operations and, later, for some commercial flights. It subsequently shut down operations sporadically due to aftershocks, and on 3 May was closed temporarily to the largest planes for fear of runway damage. During strong aftershocks, the airport opened all boarding-lounge exit doors onto the tarmac, allowing people who were waiting post security and immigration to flee to the open spaces of the runway tarmac. Many remained outside as planes were delayed and the airport swelled to capacity. The airport facilities suffered damage and there was no running water or operating toilets in the airport lounges. Few airport workers were at their posts; most were killed in the earthquake or had to deal with its aftereffects.

Flights resumed from Pokhara, to the west of the epicentre, on 27 April.

Several of the churches in the Kathmandu valley were destroyed. As Saturday is the principal day of Christian worship in Nepal, 500 people were reported to have died in the collapses.

Several temples on Kathmandu Durbar Square, a UNESCO World Heritage Site, collapsed, as did the Dharahara tower, built in 1832; the collapse of the latter structure killed at least 180 people, Manakamana Temple in Gorkha, previously damaged in an earlier quake, tilted several inches further. The northern side of Janaki Mandir in Janakpur was reported to have been damaged. Several temples, including Kasthamandap, Panchtale temple, the top levels of the nine-story Basantapur Durbar, the Dasa Avtar temple and two shrines located behind the Shiva Parvati temple were demolished by the quake. Some other monuments including the Taleju Bhawani Temple partially collapsed.

The top of the Jaya Bageshwari Temple in Gaushala and some parts of the Pashupatinath Temple, Swyambhunath, Boudhanath Stupa, Ratna Mandir, inside Rani Pokhari, and Durbar High School have been destroyed.

In Patan, the Char Narayan Mandir, the statue of Yog Narendra Malla, a pati inside Patan Durbar Square, the Taleju Temple, the Hari Shankar, Uma Maheshwar Temple and the Machhindranath Temple in Bungamati were destroyed. In Tripureshwar, the Kal Mochan Ghat, a temple inspired by Mughal architecture, was completely destroyed and the nearby Tripura Sundari also suffered significant damage. In Bhaktapur, several monuments, including the Phasi Deva temple, the Chardham temple and the 17th century Vatsala Durga Temple were fully or partially destroyed.

Outside the Valley, the Manakamana Temple in Gorkha, the Gorkha Durbar, the Palanchok Bhagwati, in Kabhrepalanchok District, the Rani Mahal in Palpa District, the Churiyamai in Makwanpur District, the Dolakha Bhimsensthan in Dolakha District, and the Nuwakot Durbar suffered varying degrees of damage. Historian Prushottam Lochan Shrestha stated, "We have lost most of the monuments that had been designated as World Heritage Sites in Kathmandu, Bhaktapur and Lalitpur District, Nepal. They cannot be restored to their original states." The northeastern parts of India also received major damage. Heavy shocks were felt in the states of Uttrakhand, Uttar Pradesh, West Bengal and others. Huge damage was caused to the property and the lives of the people.

File:Nepal Earthquake 2015 01.jpg, Building damage as a result of the earthquake
File:Gorkha Earthquake Effect.jpg, Damaged building in Balaju area

Economic loss

Concern was expressed that harvests could be reduced or lost this season as people affected by the earthquake would have only a short time to plant crops before the onset of the Monsoon rains.

Nepal, with a total Gross Domestic Product of US$19.921 billion (according to a 2012 estimate), is one of Asia's poorest countries, and has little ability to fund a major reconstruction effort on its own. Even before the quake, the Asian Development Bank estimated that it would need to spend about four times more than it currently does annually on infrastructure through to 2020 to attract investment. The U.S. Geological Survey initially estimated economic losses from the tremor at 9 per cent to 50 per cent of gross domestic product, with a best guess of 35 per cent. "It's too hard for now to tell the extent of the damage and the effect on Nepal's GDP", according to Hun Kim, an Asian Development Bank (ADB) official. The ADB said on the 28th that it would provide a US$3 million grant to Nepal for immediate relief efforts, and up to US$200 million for the first phase of rehabilitation.

Rajiv Biswas, an economist at a Colorado-based consultancy, said that rebuilding the economy will need international effort over the next few years as it could "easily exceed" US$5 billion.

More recent studies estimate the damage from the earthquake to be closer to US$10 billion (which would be around 50% of Nepals GDP at the time).

Social effects

It was reported that the survivors were preyed upon by human traffickers involved in the supply of girls and women to the brothels of South Asia. These traffickers took advantage of the chaos that resulted from the aftermath of the earthquake. The most affected were women from poor communities who lost their homes. In response to the unsafe conditions of the temporary campsites, international organizations implemented Safety Committees which were provided cash grants for necessities like additional toilets and bathrooms.

Most affected

Single women had very little access to relief, according to a report by the Inter-party Women's Alliance (IPWA). The report also found that violence and rapes against women and minors have increased after the earthquake. Additionally, the earthquake has significantly affected certain groups of people. Tibeto-Burman peoples were hardest hit as they tend to inhabit the higher slopes of mountains as opposed to the central valleys and are less educated and connected. All of these factors make them harder to access. According to a government survey, malnutrition in children has worsened considerably some 3 months after the quake, with the most undernourished being Tamang and Chepang peoples.http://www.ekantipur.com/2015/07/30/national/malnutrition-stalks-quake-hit-kids/408642.html The Kathmandu Post: Malnutrition stalks quake-hit kids Before the quake, 41 percent of children under five were stunted, 29 percent were underweight and 11 percent were emaciated, according to the World Food Programme.

Disease

Though a feared mass cholera outbreak failed to materialize (there were sporadic reports), other outbreaks were reported. At least 13 people died of scrub typhus