Analysis of ground motion in Delhi from earthquakes recorded by strong motion network
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ORIGINAL PAPER
Analysis of ground motion in Delhi from earthquakes recorded by strong motion network Himanshu Mittal & Ashok Kumar & Arjun Kumar & Rohtash Kumar
Received: 24 September 2013 / Accepted: 5 March 2014 # Saudi Society for Geosciences 2014
Abstract In the present study, ground motions for Mw5.0, 5.5, and 6.0 scenario earthquakes are estimated at one hard rock site Delhi Jal Board (DJB) in Delhi using the empirical Green’s function technique. The recordings of the 7th September 2011 earthquake of Mw3.9 at the DJB site are used as an element earthquake. Our computations show that an Mw5.0 earthquake would give rise to peak ground acceleration (PGA) of ∼50 to 250 cm/s2, the smaller values occurring at hard sites. The corresponding estimated PGV range is ∼3 to 10 cm/s. Mw5.5 earthquake would give rise to PGA of ∼80 to 350 cm/s2, while during Mw6.0 PGA of ∼150 to 670 cm/s2 may occur at different sites. The estimated response spectra are compared with earlier studies in the same region by different researchers and it is found that the results are comparable. The obtained spectral acceleration values can be used in identifying the vulnerable areas in Delhi, thereby facilitating the planning, design, and construction of new structures and strengthening of the existing structures in the region.
Keywords Delhi . DJB . NDI (IMD) . 7th September . SSR
H. Mittal (*) Centre of Excellence in Disaster Mitigation and Management, Indian Institute of Technology, Roorkee, India e-mail: [email protected] A. Kumar : A. Kumar : R. Kumar Department of Earthquake Engineering, Indian Institute of Technology, Roorkee, India A. Kumar e-mail: [email protected] A. Kumar e-mail: [email protected] R. Kumar e-mail: [email protected]
Introduction Studies conducted on strong motion records of several earthquakes in and around India have adequately confirmed the presence of large concentrations of pockets of high amplification due to site-dependent factors related to local ground conditions (Aki 1988). Brutal damage even at large epicentral distances have taken place due to the local site effects during past earthquakes. The number of persons affected by earthquake catastrophes around the world has been increasing and calls for the integrated planning of cities and in selecting the location of new structures that are more suited to an area, along with information on the relative damage potential of the existing structures in a region to neutralize and diminish the terrible effects of earthquakes. The observation of strong motion and the investigation of the destruction from these earthquakes provide the disciplines of seismology and earthquake engineering with informative and valuable data, experiences, and lessons, and raise a number of important scientific challenges. The Himalayas are among the most seismically active regions in the world, and has experienced several earthquake disasters during historical times. In the last 50 years, the population of India has doubled and resulted in a very rapid growth of settleme
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