No abstract

Ground motion models (GMMs) are an essential tool for seismic hazard analysis. They are used for developing predictive relationships to estimate the expected levels of seismic ground shaking through the ground motion parameters (GMPs). There is limited recorded data on the stable continental regions (SCR) such as Peninsular India (PI), and Central and North Eastern America (CENA), and GMMs are developed either by hybrid or stochastic methods. In this study, an effort has been made to develop a GMM for the PI region by compiling the recorded data from the CENA and PI regions, as well as from the Near Source Strong (NESS) data. An artificial neural network coupled with the genetic algorithm is considered to develop GMMs. So, the GMP-1 model is developed for various GMPs for both RotD50 and vertical components, while the GMP-2 model is developed for RotD50 components of peak ground acceleration (PGA), peak ground velocity (PGV), and the 5% damped pseudo-spectral acceleration (PSA) for periods between 0.01 and 3 s. The developed models are valid for magnitudes between 2–7.7 Mw and 0 to 1500 km Joyner–Boore distance. In addition, a parametric study is performed with the developed models for various combinations of predictor variables, and it is noticed that both the models capture the trend and attenuation pattern observed in the recorded data for all the GMPs. Moreover, the GMP-2 model predictions agree well with the recorded data compared with the candidate GMMs developed in the NGA-EAST project. A comparison of the GMP-2 models with the recorded data in the PI region indicates the robustness and effectiveness of the developed model in providing reasonable estimates of GMPs, implying its applicability to tectonic environments similar to the CENA region.

<p>In recent years, estimating the possible ground motion on the Moon became quite essential as various researchers are exploring safe extra-terrestrial habitats close to the Earth. From the high-resolution imageries, it is observed that seismic sources like lobate scarps and wrinkle ridges are identified representing that there is seismic activity on the Moon which is considered a hazard to the lunar base. Therefore, it is essential to include topographic amplification factors in the ground motion predictions on the Moon which are in turn used in the seismic hazard analysis. It is well known that there is a wide variation of topographical features in the lunar south pole region (LSPR). Hence in this study, the spectral element method is preferred to model the seismic wave propagation in such complex topographic regions. The main objective of this study is to estimate the ground motion amplification on the Artemis landing sites that are present in the LSPR region. The topography for the study region is extracted from the entire South-pole topographic map which is obtained from the LRO-LOLA. A grid elevation data is incorporated with a resolution of 30m. The shallow moonquake event that occurred on March 13, 1973, is considered a seismic source, located at [84⁰ S, 134⁰ W] and has a focal depth of 5 km. The seismic wave simulations can generate up to a frequency of up to 2Hz from the developed model. The simulations have been performed with and without topography. The amplification ratio i.e., Peak ground displacement with topography/ Peak ground displacement without topography is calculated for the considered landing sites. In addition, an amplification map of the shake intensity maps is also generated for the considered study region. Results show that there is amplification on ridges and de-amplification in the valleys.</p>