EARTHQUAKE EARLY WARNING SYSTEM: SITE CLASSIFICATION, INTENSITY MAP AND ATTRIBUTES

Abstract

The Himalaya is one of the most seismically active regions of the world. Many Indian states are in the Himalayan region, and Uttarakhand is one of them. This region lies in seismic zones IV and V of the seismic zone map of India (IS 1893 (Part1), 2016) and is prone to seismic hazards. Seismic gap studies carried out of the Indian Himalayan region (Srivastava et al., 2015) identify a central seismic gap, namely Uttarakhand-Dharchula between Kaurik fault in Himachal-Pradesh and Main Central Thrust (MCT) near Dharchula, Nepal. The major part of the Uttarakhand falls in this seismic gap region. Many researchers have envisaged that a large earthquake is impending in this region. Therefore, an Earthquake Early Warning (EEW) System for this region can serve as a foremost tool to reduce losses due to future earthquakes. An EEW System for Uttarakhand has been developed by EEW System Laboratory, Centre of Excellence in Disaster Mitigation & Management (CoEDMM), Indian Institute of Technology (IIT) Roorkee. Now, this system is full-fledged operational. A further research study that needs to be addressed is required to be carried out. In the present thesis, an attempt has been made to fill the identified gaps. In this study, all the prevalent EEW attributes and their formulation are presented in tabular form. The empirical relationships to estimate magnitude using EEW parameters developed by different authors are also presented in a tabular form. Several authors have formulated GMPEs for the Indian Himalayan region, which are described in the literature review. Various site classification schemes used by different authors are described in the tabular form. Studies carried out by different authors in the preparation of PGA and intensity maps are explained. The developed regression relationships between Modified Mercalli Intensity (MMI) and PGA by various authors are presented in a tabular form. Finally, the research gaps are identified to address the objective to enhance the potential of existing EEW System and carried out unwinding of complexities of the earthquakes in general.