April 23, 2010 - Present
  • Hugh Roy and Lillie Cranz Cullen Distinguished University Chair in Physics
  • Professor, Dept. of Physics
  • Professor, Dept. of Earth and Atmospheric Sciences
  • University of Houston, Houston, Texas.
September 1, 2002 – April 23, 2010
  • Hugh Roy and Lillie Cranz Cullen Distinguished Professor in Physics
  • Professor, Dept. of Physics
  • Professor, Dept. of Earth and Atmospheric Sciences
  • University of Houston, Houston, Texas.
January 1, 2001 - Present
  • Director
  • Mission-Oriented Seismic Research Program
  • University of Houston, Houston, Texas.
February 1999 – January 2000
  • Visiting Professor and Member, Board of Directors.
  • DELPHI Project, Applied Physics Dept., Delft University of Technology, Delft, The Netherlands.
June 1982 – 1992
  • Adjunct Associate Professor
  • Columbia University, Aldridge Laboratory New York City, New York.
August 1989 – July 1990
  • Visiting Professor at PPPG/UFBA
  • Graduate Program
  • Federal University of Bahia, Salvador, Brazil.
June 1982 – December 1992
  • Lecturer and Adjunct Research Professor
  • University of Texas at Dallas, Programs in Mathematical Sciences.