Systematic review on inverse GRA methodologies developed for the determination of dynamic soil properties using downhole seismic array records
- Vol.52(2), April
- New York Springer 2022
- 400-415p.
Effect of local soil in amplifying bedrock motion during earthquakes (EQs) is an important phenomenon, observed globally. As a result, even at larger distances from the epicentre, significant ground shaking and subsequent damages are witnessed. Understanding local soil effect (LSE) requires information about subsoil type as well as corresponding dynamic soil property curves (DSPCs). Though attempts have been made globally to understand local site effect, majority of such studies used DSPCs developed for other regions. In such cases, whether the outcomes represent actual surface seismic scenario for the region under study, is a matter of debate. It must be mentioned here that while the dynamic soil properties can be determined in laboratory, such findings are affected by sampling disturbance, equipment compliance etc. Downhole seismic array records on the other hand provide actual soil response during various EQs and thus are very useful in determining regional DSPCs through inverse ground response analysis (IGRA). To do IGRA, two main methodologies (based on time domain and frequency domain) exist. This work firstly presents a systematic review on existing IGRA methodologies (both time domain and frequency domain based). Later, in the light of the importance of IGRA to determine regional DSPC, few Research Questions (RQs) are framed. Answers to such RQs are then found in terms of Research Findings (RFs) from the systematic reviews highlighting the limitations of existing methodologies, importance of ground motion characteristics in different methodologies. Based on the present endevour, it is concluded that though frameworks to determine shear modulus (G) based on IGRA exist, no such framework to is available determine damping ratio (β).