A major magnitude earthquake struck central Nepal on April 25, , The overall economic cost of the Nepal earthquake(s) – including damage in Nepal. NEPAL. NEPAL EARTHQUAKE. April – September peypredkoefritlec.gq FLASH APPEAL It was first issued on 29 April and revised on 29 May. PDF | The Gorkha Nepal earthquake caused tremendous damage and loss. To gain valuable lessons from this tragic event.
|Language:||English, Spanish, Hindi|
|Genre:||Health & Fitness|
|Distribution:||Free* [*Register to download]|
conduct this study ―Nepal Earthquake A Socio-demographic Impact Study more: peypredkoefritlec.gq%peypredkoefritlec.gq signatures of the April 25, Nepal earthquake and the relative role of High-resolution figures should be provided in the following format; PDF ( preferred. NEPAL EARTHQUAKE Country Update and Funding Request. May Contact: Country Office: Frank Paulin [email protected]
To share the gathered damage data widely, the collected damage data geo-tagged photos and observation comments are organized using Google Earth and the kmz file is made publicly available. Introduction An intense ground shaking struck Central Nepal on 25 April local time a. The moment magnitude of the earthquake was Mw7.
The earthquake occurred at the subduction interface along the Himalayan arc between the Indian plate and the Eurasian plate Avouac, ; Ader et al. The earthquake rupture propagated from west to east and from deep to shallow parts of the shallowly dipping fault plane [ United States Geological Survey USGS , ], and consequently, strong shaking was experienced in Kathmandu and the surrounding municipalities. This was the largest event since , Mw8.
Moreover, aftershock occurrence has been active since the mainshock; several major aftershocks e. As of 26 May , the earthquake damage statistics for Nepal from the 25 April mainshock stand at the total number of 8, deaths and missing 1.
Earthquake field observations provide raw damage data of existing built environments and are useful for developing empirical correlation between ground motion intensity and damage severity for earthquake impact assessment of future events. To gain valuable lessons from this tragic event, an earthquake damage investigation team was jointly organized by the Japan Society of Civil Engineers and the Japan Geotechnical Society, and was dispatched to Nepal from 1 May to 7 May The survey trip was planned in such away that relatively large geographical areas that were affected by the earthquakes were covered to grasp spatial features of the damage in the earthquake-hit regions.
A unique aspect of this damage investigation is that the data were collected at the early stage of disaster response and recovery 6—11 days after the mainshock , and thus first-hand earthquake damage observations were obtained before major repair work. The collected damage data, in the form of geo-tagged photos and some measurements e. To achieve this goal, damage photos that were taken during the survey trip are organized using Google Earth and are made publicly available; the kmz file is provided as supplementary resource of this paper.
Viewers can download the photos directly and can use them for research and educational purposes; all photos are geo-tagged and are accompanied by brief comments. This paper summarizes key findings of ground shaking damage in Nepal, and is organized as follows.
To link building damage observations with available seismological data, seismotectonic setting of Nepal is reviewed, and earthquake rupture process and aftershock data, which are available from the U.
Geological Survey USGS , are analyzed to gain scientific insights into ground motions that were experienced during the mainshock and major aftershocks.
It is important to note that strong motion observation networks in Nepal are not well developed and data are not publicly accessible.
This means that the estimation of observed ground motions at building damage sites is highly uncertain. Currently, recorded time-history data of strong motion are only available at the KATNP station, which is located in the city center of Kathmandu.
In this study, strong motion data at KATNP are analyzed and the results, in the form of elastic response spectra, are discussed by comparing with relevant ground motion prediction models [e. Furthermore, issues related to ground motion estimation for prompt earthquake impact assessment [e. Such investigations provide new insights for improvements in producing more reliable scenario shake maps and prompt earthquake impact assessments Goda and Atkinson, Subsequently, building typology in Nepal is reviewed briefly, followed by earthquake damage observations in Kathmandu, Melamchi, Trishuli, and Baluwa.
Finally, key lessons from the Nepal earthquake are summarized. Regional Seismicity and Ground Motion This section aims at providing with relevant seismological information for interpreting earthquake damage survey observations in Nepal which are discussed in the following section.
First, seismotectonic and seismological aspects of the on-going mainshock—aftershock sequence are reviewed by analyzing available earthquake catalog data and source rupture models of the mainshock. Subsequently, scenario shake maps are generated by considering different source-to-site distance measures to highlight the influence of finite-fault source representation for a large earthquake in applications to prompt earthquake impact assessment.
Seismotectonic Setting and Seismic Hazard in Nepal Nepal is located along the active Main Himalayan Thrust arc, where the subducting Indian plate and the overriding Eurasian plate interact. This region accommodates approximately a half of the tectonic convergence between these two plates, i.
Historically, Nepal hosted several large earthquakes Ambraseys and Douglas, ; Bilham, A map of Nepal and locations of major historical seismic events are shown in Figure 1. Western Nepal experienced a Mw8. This event occurred west of the rupture zone of the earthquake and accumulated strain in this seismic gap region has not been released since then; thus, there is high potential for future large earthquakes in the western region.
In Eastern Nepal, two known major earthquakes occurred in and In particular, the Mw8. The Gorkha—Kodari earthquakes have ruptured a fault section that overlaps with the fault rupture plane of the earthquake see Figure 1. It is noted that the rupture planes of the and earthquakes are directly beneath Kathmandu, although the locations of their hypocenters are east and west of Kathmandu, respectively. Major historical earthquakes in Nepal along the Himalayan arc.
The locations of three historical earthquakes , , and are approximate.
For the Mw7. Recently, several probabilistic seismic hazard studies have been conducted for Nepal by employing updated seismic source zone models based on improved earthquake catalogs and modern ground motion models [e.
These hazard estimates are obtained for rock sites, therefore, when typical soil sites are considered e. Fault Rupture Model of the 25 April Mainshock Several earthquake rupture models for the mainshock have been developed [e. A common feature of the estimated slip distributions is that large slips occurred north and north—east of Kathmandu, and the rupture propagated from the hypocenter north—west of Kathmandu toward east as well as south deeper to shallower depth.
Figure 3 overlays the route of the survey trip over the USGS source model to put visited locations i. The USGS source model has its maximum slip of 3.
It is also interesting to observe that the estimated slip near the hypocenter is 1. By analyzing numerous earthquake rupture models statistically, Mai et al. The rupture nucleation of the mainshock i. A Aftershock distribution of the earthquake sequence; an earthquake source model by the USGS is shown. B Gutenberg—Richter relationship of the earthquake sequence. C Modified Omori law of the earthquake sequence.
Earthquake damage survey locations. Aftershocks In post-earthquake situations, one of the major concerns for evacuees and emergency response teams is the occurrence of major aftershocks, triggering secondary hazards.
Generally, a larger earthquake is followed by more aftershocks, and returning to a background level of seismic activities takes longer. Figure 2 A shows the spatial distribution of aftershocks that occurred before 25 May 30 days since the mainshock. Immediately after the mainshock, a moderate Mw6.
On the other hand, the majority of aftershocks occurred in the Kodari region north—east of Kathmandu ; a notable event was the 12 May Mw7. Comparison of the aftershock distribution with respect to the slip distribution of the mainshock indicates that the major aftershocks do not occur very near to the mainshock asperity with large slip but they occur in the surrounding areas of the mainshock asperity.
This is because the spatial and temporal characteristics of aftershocks are the manifestation of internal crustal dynamics involving the redistribution of stress and displacement fields Stern, ; Heuret et al. To gain further insights into the aftershock occurrence process of the mainshock—aftershock sequence, statistical analysis of aftershock data is carried out by applying the Gutenberg—Richter law and the modified Omori law Shcherbakov et al.
The Gutenberg—Richter law describes the frequency—magnitude characteristics of an aftershock sequence, whereas the modified Omori law models a temporal decay of an aftershock occurrence rate. The fitting of the Nepal aftershock data to the Gutenberg—Richter relationship is satisfactory Figure 2 B ; the estimated slope parameter i. This slope is slightly gentler i. The obtained parameters are typical for global subduction earthquakes Shcherbakov et al.
For example, the temporal decay parameter i. The above results support the applicability of well-established empirical laws for characterizing the Nepal aftershock data. This is a useful confirmation from seismic risk management viewpoints because initial estimates of aftershock-related hazard can be obtained from the empirical aftershock models immediately after the mainshock before real-time data are collected and analyzed.
In light of poor strong motion network in Nepal, the recorded ground motion data at KATNP are invaluable and serve as a benchmark in estimating ground motion intensity at unobserved locations in Kathmandu. Figure 4 shows the location of the KATNP station; the map also shows the locations of the earthquake damage survey sites in Kathmandu.
Prior to ground motion data analysis and estimation, it is important to review typical site conditions in Kathmandu, as they affect ground motion intensity significantly. Kathmandu is located in the Kathmandu Basin, where thick lacustrine and fluvio-lacustrine sediments are deposited Sakai et al.
The thickness of sediments i. A seismic microzonation study in Kathmandu, conducted by Paudyal et al. Another useful source of information in assessing site amplification potential of near-surface soil deposits in Kathmandu is the USGS global VS30 server Wald and Allen, 4. VS30 is the average shear-wave velocity in the uppermost 30 m and is often employed as a proxy site parameter in ground motion models [e.
Wald and Allen correlated VS30 data with topographic slope to derive the first-order estimate of the site amplification for two tectonic regimes, active and stable continental regions. Figure 4 shows the VS30 contour map in Kathmandu. In Bhaktapur, several monuments, including the Phasi Deva temple, the Chardham temple and the 17th century Vatsala Durga Temple were fully or partially destroyed.
They cannot be restored to their original states. Huge damage was caused to the property and the lives of the people. Economic loss[ edit ] Road damage in Nepal 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.
Geological Survey initially estimated economic losses from the tremor at 9 percent to 50 percent of gross domestic product, with a best guess of 35 percent.
These traffickers took advantage of the chaos that resulted from the aftermath of the earthquake. The report also found that violence and rapes against women and minors has increased after the earthquake. 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.
The people of Nepal acknowledged the aid and effort put by the Indian armed forces, yet, at the same time, accused Indian news networks of carrying out "a public relations exercise" on behalf of the Indian government, of overemphasizing the role of the Indian Army, and of hogging space on relief planes where aid material or rescue or medical personnel could have been sent instead.
BMJ Nepali earthquakes and the risk of an epidemic of hepatitis E. Lancet Infectious diseases following natural disasters: Expert Rev Anti Infect Ther 10 1: Nayak N. Earthquake aftermath-myth or reality? Nepal J Epidemiol 5 2: Negligible risk for epidemics after geophysical disasters.
Emerg Infect Dis 12 4: Health education and promotion at the site of an emergency: Glob Health Promot 23 1: Prepared for what? Addressing the disaster readiness gap beyond preparedness for survival. BMC Public Health 15 1: Building resiliency: Health Qual Life Outcomes J Adv Med Educ Prof 3 2: United Nations. Pun SB. Stay Alert. Republica; Central Bureau of Statistics, Government of Nepal. Post-earthquake Nepal: Lancet Glob Health 3 Prevention of communicable diseases after disaster: J Res Med Sci 16 7: Chan M.
Ebola virus disease in West Africa — no early end to the outbreak. N Engl J Med Communicable diseases in complex emergencies: Challenges and future perspective for dengue vector control in the Western Pacific Region.
Western Pac Surveill Response J 2 2: Communitywide shigellosis: Am J Public Health 85 6: Community-based hygiene education to reduce diarrhoeal disease in rural Zaire: Int J Epidemiol 23 5: Nepal Disaster Management Reference Handbook. Government of Nepal. National Strategy for Disaster Management in Nepal. Lee ACK. Barriers to evidence-based disaster management in Nepal: Public Health World Health Organization.
Community Engagement and Social Mobilization. Community Engagement in Disaster Planning and Response. Boston, MA: Community-directed interventions for priority health problems in Africa: