Eos,Vol. 81, No. 32, August 8,2000

SECTION NEWS V O L C A N O L O G Y G E O C H E M I S T R Y & P E T R O L O G Y

Editor: Johan C.Varekamp, Department of Earth and Environmental Sciences, Wesleyan University, Middletown CT 06459-0139 USA Tel: +1-860-685-2248; Fax: +1-860-685-3651; Section President, Frederick A. Frey; Section Secretary, Donald B. Dingwell

Outstanding Student Paper Awards PAGE 364

The Volcanology, Geochemistry & Petrology Section presented three outstanding student paper awards at the 2000 AGU Spring Meeting in Washington, D. C., last June.

Darren R. Locke presented a paper titled "Experimental Determination of H 2 0

Solubility in Mantle Clinopyroxene at 5 and 7.5 Gpa." Darren received his B.S. in geology from Norwich University, Vermont, in 1997, and earned an M.S. in geology from the University of Cincinnati in

1999, under Attila Kilinc. He recently com­pleted his first year of the Ph.D. program in geology at Arizona State University under the direction of John Holloway. Darren s research interests include thermodynamic modeling of various aspects of subduction zones, including thermal structure and the genera­tion of partial melts, and in coordination with Jim Tyburczy measurement of electrical conductivity of hydrated mantle materials.

Lesley A. Rose presented a poster titled "Wetting Properties of Fe-Cu-Ni-Co-O-S Melts against Olivine: Implications for Sulfide Melt Mobility" Lesley received her B.Sc. in Earth

science at the Uni­versity of Western Ontario, Canada. She is currently complet­ing an M.Sc.in experimental igneous petrology under the supervision of James Brenan at the Univer­sity of Toronto,

Canada. Lesley's research focuses on the dis­tribution of sulfide liquid within the crust and upper mantle environments.

Martin O. Saar presented a paper titled "Determining Onset of Minimum Yield Strength

in Crystal-Melt Suspensions Using a Percolation Theory Approach ."Martin re­ceived hisVordiplom in geology from Freiburg University, Germany, in 1995, and an M.Sc. in geology from the University of Oregon in 1998. He is

now in his second year as a Ph.D. student at the University of Oregon working with Michael Manga and Katharine Cashman. Martins research interests include volcanological fluid mechan­ics, transport properties of porous media, and coupled temperature-groundwater modeling.

BOOK REVIEWS Seismic Inversion and Deconvolution: Dual-sensor Technology PAGE 368

ENDERS A . ROBINSON Pergamon Press, New York, 348 pp.,

ISBN 0-08-043627-7,1999, $129.50.

Ocean bottom cables and dual-sensor record­ings at the sea floor are becoming increasingly popular tools for marine seismic exploration. They offer several advantages for seismic data processing, including multiple attenuation, ghost reflection removal, and direct measurement of converted shear waves at the sea floor. New tech­niques for processing these unconventional data are actively being developed.A book that specifi­cally addresses the dual-sensor technology writ­ten by Enders A. Robinson—one of the pioneers of seismic data processing—is therefore a welcome addition to the geophysical literature.

Seismic energy undergoes multiple reflections between the sea floor and the sea surface.These free surface multiples and the internal multiple reflections through sediment contaminate the recorded signal. As Robinson correctly points out in this book,"It is remarkable that the seismic

reflection method based on primary reflections works as well as it does."

Most commonly used multiple attenuation methods employ some form of wave equation to predict the multiples and subtract them from the data.The alternative approach is to obtain sepa­rate estimates of the upgoing and downgoing energy and to carry out the deconvolution pro­cess on the upgoing signal. Since it is extremely difficult, if not impossible, to separate upgoing and downgoing waves from data measured at a single depth level, measurements at two or more depth levels recorded on a vertical cable or at two different types of sensors (hydrophone and geophone-called dual sensor) are needed. Robinson describes the historical details, the theoretical developments, and processing tech­niques of dual-sensor data.

Much of the theoretical development in the book is based on the authors well-known work on digital filter theory Chapters 2 through 5 describe the concepts of convolution, correlation, least squares filter,and other related topics in great detail.Though these discussions can be found in the authors earlier textbooks,

these chapters are welcome, as they make the book self-contained.The author introduces the dual sensors in chapter 6.This is, to my knowledge, the first document to describe the history of this technology and would prove use­ful to everyone working in this area.

The remaining chapters are devoted to one-dimensional reflection seismograms, multiple gener­ation, predictive deconvolution, Einstein decon­volution, and other methods of deconvolution, including Homomorphic deconvolution—all that you would ever want to learn about deconvolution.

Many of the deconvolution methods are well established and used commonly in seis­mic data processing.They include spiking deconvolution and predictive deconvolution pioneered by the author and his colleague, Sven Treitel.The deconvolution of dual sensor data is becoming more popular.The authors' use of the term "Einstein deconvolution" to describe the deconvolution of dual sensor data is rather intriguing and is based on clear physics. I found the explanation of Newton's and Einstein's addition formula in this context truly enlightening. Robinson continues to be the excellent teacher that he always has been.

To quote Robinson,"Predictive deconvolution is robust and stable in the presence of noise... Einstein deconvolution is more general. However, Einstein deconvolution is more sensitive to noise."

These statements clearly describe the limitations of the two techniques. I completely agree with these statements. In many situa­tions, I was able to obtain a more stable result with predictive deconvolution of plane wave