Simulation-based PSHA for the Kathmandu Valley: sensitivity to hypocentre randomisation

Raffaele De Risi; Shaoqing Wang; Max Werner; Flavia De Luca; Paul J Vardanega; Rama Pokhrel; Prem Maskey; Anastasios Sextos

Simulation-based PSHA for the Kathmandu Valley: sensitivity to hypocentre randomisation

Raffaele De Risi, Shaoqing Wang, Max Werner, Flavia De Luca, Paul J Vardanega, Rama Pokhrel, Prem Maskey, Anastasios Sextos

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Abstract

This paper presents a sensitivity study of simulation-based Probabilistic Seismic Hazard Analysis (PSHA) for Kathmandu, Nepal. Two aspects are investigated in detail: (i) the technique for simulating fault ruptures compatible with scaling laws and fitting into the Main Himalayan Trust (MHT) and (ii) the choice of different Ground Motion Prediction Equations (GMPEs). Since the 2015 Gorkha earthquake, a number of new studies have provided new approaches to model the MHT as a single seismic source. This more realistic characterization of the MHT has resulted in higher peak ground acceleration (PGA) for all of Nepal and in particular for the Kathmandu Valley. Here, the results of a new simulation-based code are compared with those by the software OpenQuake. It is specifically assessed how different source simulation methods influence the hazard calculations. Furthermore, the influence of different GMPEs assumed for subduction earthquakes is assessed for the specific case of Kathmandu, which is only 11 km above the MHT. Results show that because of the proximity to the megathrust, the estimated hazard is very sensitive to different choices.
The results of this study may be useful for informing ongoing efforts in Nepal to update the building code with a new seismic hazard map. Understanding the sensitivity and robustness of PSHA is critical from a policy and preparedness perspective.

Original language	English
Number of pages	9
Publication status	Published - 18 Sept 2020
Event	The 17th World Conference on Earthquake Engineering - Sendai, Japan Duration: 27 Sept 2021 → 2 Oct 2021

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Conference	The 17th World Conference on Earthquake Engineering
Country/Territory	Japan
Period	27/09/21 → 2/10/21

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SAFER Seismic safety and resilience of schools in Nepal
Sextos, A. (Principal Investigator), De Luca, F. (Co-Investigator), Vardanega, P. J. (Co-Investigator), Agarwal, J. (Co-Investigator), Alexander, N. A. (Co-Investigator) & Werner, M. (Co-Investigator)
1/05/17 → 30/06/21
Project: Research, Parent

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@conference{7e0fdc6b18694cfd9a68edaed6581c41,

title = "Simulation-based PSHA for the Kathmandu Valley: sensitivity to hypocentre randomisation ",

abstract = "This paper presents a sensitivity study of simulation-based Probabilistic Seismic Hazard Analysis (PSHA) for Kathmandu, Nepal. Two aspects are investigated in detail: (i) the technique for simulating fault ruptures compatible with scaling laws and fitting into the Main Himalayan Trust (MHT) and (ii) the choice of different Ground Motion Prediction Equations (GMPEs). Since the 2015 Gorkha earthquake, a number of new studies have provided new approaches to model the MHT as a single seismic source. This more realistic characterization of the MHT has resulted in higher peak ground acceleration (PGA) for all of Nepal and in particular for the Kathmandu Valley. Here, the results of a new simulation-based code are compared with those by the software OpenQuake. It is specifically assessed how different source simulation methods influence the hazard calculations. Furthermore, the influence of different GMPEs assumed for subduction earthquakes is assessed for the specific case of Kathmandu, which is only 11 km above the MHT. Results show that because of the proximity to the megathrust, the estimated hazard is very sensitive to different choices.The results of this study may be useful for informing ongoing efforts in Nepal to update the building code with a new seismic hazard map. Understanding the sensitivity and robustness of PSHA is critical from a policy and preparedness perspective.",

author = "{De Risi}, Raffaele and Shaoqing Wang and Max Werner and {De Luca}, Flavia and Vardanega, {Paul J} and Rama Pokhrel and Prem Maskey and Anastasios Sextos",

year = "2020",

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day = "18",

language = "English",

note = "The 17th World Conference on Earthquake Engineering ; Conference date: 27-09-2021 Through 02-10-2021",

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TY - CONF

T1 - Simulation-based PSHA for the Kathmandu Valley

T2 - The 17th World Conference on Earthquake Engineering

AU - De Risi, Raffaele

AU - Wang, Shaoqing

AU - Werner, Max

AU - De Luca, Flavia

AU - Vardanega, Paul J

AU - Pokhrel, Rama

AU - Maskey, Prem

AU - Sextos, Anastasios

PY - 2020/9/18

Y1 - 2020/9/18

N2 - This paper presents a sensitivity study of simulation-based Probabilistic Seismic Hazard Analysis (PSHA) for Kathmandu, Nepal. Two aspects are investigated in detail: (i) the technique for simulating fault ruptures compatible with scaling laws and fitting into the Main Himalayan Trust (MHT) and (ii) the choice of different Ground Motion Prediction Equations (GMPEs). Since the 2015 Gorkha earthquake, a number of new studies have provided new approaches to model the MHT as a single seismic source. This more realistic characterization of the MHT has resulted in higher peak ground acceleration (PGA) for all of Nepal and in particular for the Kathmandu Valley. Here, the results of a new simulation-based code are compared with those by the software OpenQuake. It is specifically assessed how different source simulation methods influence the hazard calculations. Furthermore, the influence of different GMPEs assumed for subduction earthquakes is assessed for the specific case of Kathmandu, which is only 11 km above the MHT. Results show that because of the proximity to the megathrust, the estimated hazard is very sensitive to different choices.The results of this study may be useful for informing ongoing efforts in Nepal to update the building code with a new seismic hazard map. Understanding the sensitivity and robustness of PSHA is critical from a policy and preparedness perspective.

AB - This paper presents a sensitivity study of simulation-based Probabilistic Seismic Hazard Analysis (PSHA) for Kathmandu, Nepal. Two aspects are investigated in detail: (i) the technique for simulating fault ruptures compatible with scaling laws and fitting into the Main Himalayan Trust (MHT) and (ii) the choice of different Ground Motion Prediction Equations (GMPEs). Since the 2015 Gorkha earthquake, a number of new studies have provided new approaches to model the MHT as a single seismic source. This more realistic characterization of the MHT has resulted in higher peak ground acceleration (PGA) for all of Nepal and in particular for the Kathmandu Valley. Here, the results of a new simulation-based code are compared with those by the software OpenQuake. It is specifically assessed how different source simulation methods influence the hazard calculations. Furthermore, the influence of different GMPEs assumed for subduction earthquakes is assessed for the specific case of Kathmandu, which is only 11 km above the MHT. Results show that because of the proximity to the megathrust, the estimated hazard is very sensitive to different choices.The results of this study may be useful for informing ongoing efforts in Nepal to update the building code with a new seismic hazard map. Understanding the sensitivity and robustness of PSHA is critical from a policy and preparedness perspective.

M3 - Conference Paper

Y2 - 27 September 2021 through 2 October 2021

ER -

Simulation-based PSHA for the Kathmandu Valley: sensitivity to hypocentre randomisation

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SAFER Seismic safety and resilience of schools in Nepal

Cite this