Time Series Analysis & Geophysical Data Modelling

Dr.Kirti Srivastava, Chief Scientist & Divisional Head Project Leader: MLP-6401-28(KSV)

Theoretical Modelling Group

Project Title: MLP-6401-28(KSV)

INDEX Project: Analysis and Modelling of extreme events using the multiple spectral and nonlinear approaches.

Complexity in the earthquake mechanism is manifested in different forms such as fractal distribution, clustering of seismicity, etc., and characterized as critical phenomenon. Occurrences of earthquakes generally represent the state of metastable equilibrium. The Andaman–Sumatra subduction zone is one of the most seismically active corridors (possibly in metastable state) in the world. Recently, the region faced three major earthquakes of magnitude more than 8.5 (M* 9.1 on December 26, 2004; M* 8.6 on March 28, 2005;M* 8.6on April 11,2012). Researchers have suggested multiple causes of earthquake generation in this region including the one with possible correlation of tidal stresses with earthquake occurrences. The latter issue, however, has been hotly debated in view of the fact that a small stress generated due to tidal forcing cannot cause such a bigger magnitude earthquake. We study here the impact of tidal forcing on critically generated earthquake phenomena. We examined the statistical behavior of recurrence time interval of earthquakes using the available data for period of about 40 years from 1973 to 2013. We constrain the simple empirical toy model using the concept of catastrophe theory to evaluate the impact of small tidal forcing on the critical state of earthquakes occurrences. In addition to the major role of Helmholtz free energy during the plate motion, our analysis suggests that the stability and critical behavior of the earthquake in Sumatra region could be associated with tidal forcing, however, only for triggering of some of the ‘‘Catastrophic–Chaotic’’ earthquake phenomenon.

  1. Time series analysis and geophysical data modeling
  2. Tidal Triggering of Earthquake Process
  3. T-X frequency filtering of seismic data using SSA
  4. Imprints of solar signals in groundwater recharge
  5. Nonlinear coupling of Solar and ENSO signals in Indian temperature
  6. Bouguer gravity data processing and interpretation

 

Bouguer gravity data of the Mahanadi Basin has been reprocessed as the previous attempts to estimate the sediment thickness in Mahanadi Basin had been inconclusive. The results obtained by modeling the residual gravity anomaly are published in the Journal of Geophysics.The Bouguer gravity data of the Koyna-warna region has been reprocessed in order to know the possible reasons for the high-order conspicuous gravity low beneath this region, seismicity,  isostatic compensation, basement geometry and Deccan trap thickness. Present study reveals the presence of two thick low-density/low-velocity crustal zones below the Koyna-Warna region. Processed and modeled the Bouguer gravity data of well known Manicouagan impact structure in order to know the accurate tectonic framework and mass deficiency.

a) Pure Synthetic trace b) Noisy synthetic trace (with 30% correlated noise) c) Output of SSA frequency filtering and d) Fourier Filtering. 

  3

Seismic reflection trace and its SSA and MSSA filtered Outputs.

  Comparision of SSA_MSSA_filterings.jpg

Staff :-

Name Designation

Dr.Abhay Ram Bansal

Principal Scientist

Mr.M.Tirupathi

Sr.Technical Officer-3

Dr.A.Vasanthi

Scientist

Mr.A.Sailu

Lab Assistant