Seismic Ground Motion Amplification in a 3D Sedimentary Basin: Source Mechanism and Intensity Measures

In this study, a probabilistic seismic hazard analysis (PSHA) using a traditional approach with a simple logic tree that handles a single-site sigma is developed to present a site-specific ground motion hazard. The analysis relies on the accelerometer data collected from the I-Lan Plain, a deep sedimentary basin in Northeastern Taiwan where hundreds of earthquake sequences (with [Formula: see text] = 4.0–7.6) were recorded by the Taiwan Strong Motion Instrument Program (TSMIP) network between 1992 and 2016. The performance of PSHA on soil and hard sites is evaluated from two representative instrumented sites (ILA048 and ILA025), using residual measures available from a ground motion model (GMM) developed by Phung et al. [ 2023 ] (referred to as Ph23), from which the uncertainties in site terms ([Formula: see text] and single-site sigma ([Formula: see text] are estimated. We address key conceptual issues in the current PSHA approach and introduce a new region- and site-specific PSHA approach in which (1) site-to-site variability ([Formula: see text] is estimated as a random variance in a mixed effects GMM regression and (2) the GMM site-specific single-site sigma ([Formula: see text] is replaced with a generic site-corrected aleatory variability ([Formula: see text]). Comparison of the region- and site-specific hazard curves from our method against the traditional method estimates at two well-recorded sites in the I-Lan region shows an approximate 50% difference in prediction ground motion values considering for 2% and 10% probability of exceedance in 50 years.

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Spatial Variation of Earthquake Hazard for Amaravati City of Peninsular India: A Probabilistic Approach

Satyannarayana,

Rajesh

2024

J. Earthquake and Tsunami

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Earthquakes begin with abrupt shifts along the faults. These movements release seismic waves that propagate through the Earth, shaking the ground as a result of the stored “elastic strain” energy being released. Property loss and human deaths occur due to improper design of structures under the earthquake loading conditions. It is observed that Peninsular India witnessed steady-to-serious earthquakes in the last 50 years. Amaravati is the prospective capital city of Andhra Pradesh State, which is situated on the Coromandel Coast of Peninsular India. The upcoming capital city, Amaravati, requires an earthquake hazard analysis because important engineering structures and infrastructure systems will be constructed in the near future. In this study, a probabilistic approach is used to assess the earthquake hazard for Amaravati City (latitudes: 16∘24[Formula: see text]36[Formula: see text]–16∘35[Formula: see text]24[Formula: see text][Formula: see text]N and longitudes: 80∘24[Formula: see text]25[Formula: see text]–80∘36[Formula: see text]18[Formula: see text][Formula: see text]E), India. The seismic risks of Amaravati City presented in terms of the configuration of ground motion parameters, peak ground acceleration (PGA), and spectral response acceleration ([Formula: see text]) at 0.05[Formula: see text]s and 1[Formula: see text]s for 2% and 10% Risks of Exceedance in 50 years, are produced. The uncertainties involved in seismic risk prediction are accounted for by selecting different attenuation relations developed for globally shallow crustal intraplate earthquakes with a logic tree approach. Additionally, the seismic risk values are disaggregated for Amaravati City (16∘31[Formula: see text]37[Formula: see text][Formula: see text]N and 80∘29[Formula: see text]46[Formula: see text][Formula: see text]E) to understand the individual contributions of seismic sources in terms of earthquake magnitude and site distance. The uniform hazard spectra are developed for the important places of the Amaravati Capital City and are compared with the Indian seismic code [IS 1893 (Part 1): Criteria for earthquake-resistant design of structures — Part 1: General provisions and buildings] for the rocky site. It is found that the estimated PGA values for Amaravati City are higher than the values recommended by IS 1893 (Part 1) for the rocky site. The results of this study will be very helpful for the composition of earthquake-resistant infrastructures in Amaravati City.

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Seismic Ground Motion Amplification in a 3D Sedimentary Basin: Source Mechanism and Intensity Measures

Cited by 7 publications

References 58 publications

3D high-density ambient noise imaging of the Nankou-Sunhe buried active fault in Beijing

3D high-density ambient noise imaging of the Nankou-Sunhe buried active fault in Beijing

Regional and Site-Specific Ground Motion Model for Probabilistic Seismic Hazard Analysis in Taiwan: A Case Study of I-Lan

Spatial Variation of Earthquake Hazard for Amaravati City of Peninsular India: A Probabilistic Approach

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