Magnitude calibration of north Indian earthquakes

N. N. Ambraseys, J. Douglas

Research output: Contribution to journalArticle

269 Citations (Scopus)

Abstract

This article is concerned primarily with the evaluation of the size and location of northern Indian and southern Tibetan earthquakes during the last 200 yr. It draws attention to the problems of assessing intensity of early and more recent earthquakes in a built environment, which is different from that for which the intensity scale has been constructed and to the way in which isoseismals are drawn. Through a re-evaluation of intensities and a reassessment of isoseismals, a formula for the estimation of surface wave magnitude using isoseismal radii is derived. This formula is used to estimate the surface wave magnitudes of 16 earthquakes that occurred in the region between 1803 and 1900. This study shows that it is possible to calculate accurate surface wave magnitudes for earthquakes that occurred before the advent of the scale and that there is no need to resort to empirical formulae for the assessment of the size and seismic moment release of pre-20th-century earthquakes. Also derived are formulae for the conversion of Ms to M0. In total, locations, surface wave magnitudes and M0 estimates are presented for 43 important events that occurred in the region between 1803 and 1974, eight of which were in the lower crust or were subcrustal. We find that the M0-Ms scaling for India yields smaller Ms than the global relation and that the methodology used can help to evaluate more realistic slip rates as well as to address other issues related to earthquake hazard in northern India.

Original languageEnglish
Pages (from-to)165-206
Number of pages42
JournalGeophysical Journal International
Volume159
Issue number1
DOIs
Publication statusPublished - Oct 2004

Keywords

  • earthquakes
  • Himalayas
  • intensity
  • magnitude
  • north India

Fingerprint Dive into the research topics of 'Magnitude calibration of north Indian earthquakes'. Together they form a unique fingerprint.

  • Datasets

    Intensity data points from "Magnitude calibration of north Indian earthquakes"

    Ambraseys, N. N. (Creator) & Douglas, J. (Creator), University of Strathclyde, 1 May 2018

    Dataset

    Research Output

    • 269 Citations
    • 1 Article

    Do French macroseismic intensity observations agree with expectations from the European Seismic Hazard Model 2013?

    Rey, J., Beauval, C. & Douglas, J., 9 May 2018, In : Journal of Seismology. 22, 3, p. 589-604 16 p.

    Research output: Contribution to journalArticle

    Open Access
    File
  • 5 Citations (Scopus)
    13 Downloads (Pure)

    Cite this