Building damage survey and microtremor measurements for the source region of the 2015 Gorkha, Nepal, earthquake

Yamada, Masumi; Hayashida, Takumi; Mori, Jim; Mooney, Walter D.

doi:10.1186/s40623-016-0483-4

Cited by 11 publications

(5 citation statements)

References 20 publications

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“…The epicenter was located in the eastern area of the Gorkha District at Barpak, Gorkha, and the hypocenter was at a depth of approximately 8.2 km (USGS, 2015). Many masonry buildings were seriously damaged in historic cities and towns in the Kathmandu Valley (Ohsumi et al, 2016;Yamada et al, 2016;Bhagat et al, 2018). The Nepal Disaster Risk Reduction Portal has reported the aggregate number of disaster victims (Nepal Disaster Risk Reduction Portal; as of 2022) to be 8,962 people killed, 22,302 injured, and 195 missing in all regions of Nepal.…”

Section: Introductionmentioning

confidence: 99%

Investigation of microtremors observed at historic masonry townhouse buildings after Nepal earthquake

Mukai

Hoshino²,

Yamamoto

et al. 2022

Front. Built Environ.

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The Gorkha earthquake in 2015 was a recent large-scale earthquake that caused severe damage to many historic masonry buildings in the Kathmandu Valley, Nepal. The authors conducted a visual inspection survey of seismically damaged buildings after the earthquake in the historic town district of Bhaktapur in the Kathmandu Valley. The first part of this paper reports the distribution of the historic masonry buildings for each damage level in the surveyed area. A concentrating zone of severely-damaged buildings was explicitly found in the damage-level distribution map. Almost half of all the surveyed buildings were severely damaged during the earthquake, and most of these were historic masonry townhouse buildings. In the second part, the ambient vibration characteristics of the conventional historic masonry buildings in Bhaktapur are investigated. Typical dwelling houses in a historic town district in Nepal, which generally formed terraced houses built around a courtyard, were targeted for the measurement. Thus, the influence of adjacent buildings, which makes it difficult to identify the predominant natural frequencies from building vibration measurements, was also observed. Microtremor measurements using two accelerometers were conducted at 11 historic masonry buildings to investigate the discrimination degree for identifying the predominant natural frequency of conventional townhouse buildings. The estimated primary natural frequencies of these buildings were compared with the results of the screening model analysis. The advantages of using the proposed screening model analysis to improve the uncertainty of the first natural frequency identification by the microtremor measurement are discussed. Additional measurements of the microtremors at 4 of the 11 measured buildings were conducted using a different location combination of the two acceleration sensors. The sensors were placed between two different floors, and the transfer functions of each floor were investigated to observe the predominant vibration components on the floors in the entire building. Moreover, the coherence values observing the in-plane correlation of the floor responses were also analyzed for the dataset measured at two points separated on the same floor. Finally, an effective method for measuring the microtremors is discussed to improve the assessment of the vibration characteristics of conventional historic masonry buildings in Nepal.

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Section: Introductionmentioning

confidence: 99%

Investigation of microtremors observed at historic masonry townhouse buildings after Nepal earthquake

Mukai

Hoshino²,

Yamamoto

et al. 2022

Front. Built Environ.

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“…When the authors executed research of damage of civil/architectural structures caused by Nepal Gorkha Earthquake in 2015, it was confirmed that the retaining walls using gabions are widely used in Nepal [2]. Araniko Highway, objective of the research, is located about 10km west of the place where the biggest aftershock occurred (Dolakha county), and at Barhabise along the Highway 42% of houses were completely destroyed [3]. Almost all of the retaining walls using gabions were gravity type that gabions were straightly piled up, and some of them suffered from stick out or fall forward that are considered to be affected by external factor such as earthquake (Nepal Gorkha Earthquake) and rainfall.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Numerical Analysis for Earthquake Resistance of Retaining Wall Using Gabions

Nishi¹,

Hara

Nakazawa

et al. 2019

EPI-IJE

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In developing countries, gabions are widely used in several construction works, like road, river, countermeasures against slope failure and so on, because of their easy operation and low cost. In 2015 Nepal Gorkha Earthquake, a lot of retaining walls using gabions were not damaged against the strong earthquake because of their high flexibility. However, some deformation or declination were reported dpending on retaining wall types and ground conditions behind retaining walls. Therefore, in order to evaluate the earthquake resistance and residual deformations of retaining walls using gabions widely observed in Nepal, full-scale shake table tests and laboratory tests were conducted in previous studies. In this study, elemental simulations for determination of the analysis parameters based on the results of triaxial compression tests were carried out to check the validity of parameters. Then, a series of numerical analysis using proposed model was performed to reproduce the dynamic behaviors of full-scale shake table tests and evaluate the earthquake resistance of retaining wall using gabions. According to the results of these numerical analysis, it was confirmed that proposal model adequately could simulate the dynamic response of retaining walls in the full-scale shake table tests. and it was also cleared that the stepwise type retaining wall was superior to that of vertical type from the standpoint of earthquake stability against sliding and overturning.

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“…The strong motion station at Tumaco, Colombia which is located 350 km from the damaged cities was the closest station. In the 2015 Gorkha (Nepal) M w 7.8 earthquake, many buildings were damaged in the densely populated Chautara region (Yamada et al 2016). The nearest station (i.e., KATNP) was located 28 km away from this region.…”

Section: Introductionmentioning

confidence: 99%

Aftershock Hazard Assessment Based on Utilization of Observed Main Shock Demand

Muderrisoglu

Yazgan

2018

Earthquake Spectra

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This paper presents an aftershock hazard assessment method that is based on taking into account the macroseismic indicators of the main shock observed at the site. The proposed method is referred to as conditional aftershock hazard assessment (CAHA). The essence of the CAHA method is to estimate the aftershock hazard at the site conditioned on the main shock intensity exhibited at that location. This is achieved by exploiting the correlation between the ground motion intensities exhibited during the main shock and the aftershock events. Specifically, the correlation of the epsilons registered for the two events, is utilized. Investigation of the epsilon correlation indicates that highest correlation occurs at the range of periods between 0.8 and 1.0 s. Based on the estimated epsilon correlation, the mean and the dispersion of the aftershock ground motion intensity, are estimated. An application of the proposed method to a set of sites affected by the 2011 Van (Turkey) M w7.2 earthquake sequence is illustrated. The performance of the method is assessed in comparison with the conventional approaches. For the considered example application, the hazard estimated using the proposed method shows a better agreement with the actual aftershock recordings, compared to the existing approaches.

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Building damage survey and microtremor measurements for the source region of the 2015 Gorkha, Nepal, earthquake

Cited by 11 publications

References 20 publications

Investigation of microtremors observed at historic masonry townhouse buildings after Nepal earthquake

Investigation of microtremors observed at historic masonry townhouse buildings after Nepal earthquake

Evaluation of Numerical Analysis for Earthquake Resistance of Retaining Wall Using Gabions

Aftershock Hazard Assessment Based on Utilization of Observed Main Shock Demand

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