Mapping the crustal thickness in southwest Japan using Moho-reflected waves

Mohamed K. Salah, Dapeng Zhao

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


In this work we have tried to detect and collect later phases associated with the Moho discontinuity and use them to study the lateral variations of the crustal thickness in southwest (SW) Japan. We first compute synthetic seismograms for local earthquakes taking into account the focal mechanism solutions estimated from first motion polarity data. Then we compare the synthetics with the observed waveforms to detect the major later phases in seismograms of shallow crustal earthquakes in SW Japan. Taking the advantage of the high quality and great quantity of Hi-net waveform data now available throughout the entire Japan Islands, we have detected 1659 Moho-reflected phases (PmP and SmS) from shallow events in SW Japan. We estimated the crustal thickness in the study area using travel time differences between these later phases and the first P and S arrivals. Our results show that the Moho is deep in Chubu district and becomes shallower along the coastlines of the Japan Sea and the Pacific Ocean. A thinner crust appears in Osaka Bay and Awajii Island where the 1995 Kobe earthquake (M7.2) occurred.

Original languageEnglish
Pages (from-to)79-94
Number of pages16
JournalPhysics of the Earth and Planetary Interiors
Issue number2
Publication statusPublished - 2004 Feb 16


  • Crustal thickness
  • Moho discontinuity
  • Reflected waves
  • Southwest Japan


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