Deep earthquakes are only a small fraction of seismic phenomena that take place throughout the world. They seldom cause substantial damage, and therefore, to some extent, they are outside the mainstream of interest. Further, the title of the book is somewhat misleading. Commonly earthquakes are divided into the categories of shallow, intermediate and deep. Seeing Deep Earthquakes on the shelf, I wondered what could be the use of a 573-page book about seismicity of Fiji and Tonga - as this is the region where most of the deep quakes happen. I have reached for it out of pure curiosity and surprisingly found a fascinating book on all earthquakes that take place below the crust. Actually, after some discussion, the author puts a 60-km minimum limit for what is considered a deep earthquake. The book has been written with great passion and presents the most comprehensive information on deep earthquakes that I have ever seen.

Written in a somewhat unusual tone, more common to popular science articles directed to the general public, and in popular rather, than literate, version of the English language, the book remains purely scientific. The problems covered reach from simple matters understandable to anyone who is interested in seismology, to deep down complicated concepts that are understood only by specialists. The book's unusual tone makes it easy to read, whether one is a seismological beginner, a graduate student or researcher, he (she) will always find the book interesting and useful. Even the world's leading seismologists may profit from the book since it systematizes the up-to-date findings and provides an extensive list of references. Collecting this list must have been a titanic work just by itself.

The book has no ambition to be a textbook on deep earthquakes. Instead the book presents comprehensive information on the phenomena, state-of-the-art 2006, more like a monograph. It does this job so well, and the information provided in the book is so thorough, that it falls short of the textbook objective only because of its style. As its content, the book contains what is required of a textbook - only at times directing the curious readers to some external material readily quoted.

Cliff Frohlich's book discusses all issues relevant to deep earthquakes, starting with a discussion of historical research, through earthquakes statistics, deep earthquake properties, physical mechanisms, and the importance of deep quakes to the understanding of the structure and physical processes in the deep Earth. The book is straightforward and calls things the way they are: In the case of historical papers it points out the errors if there have been any, in the discussion of earthquake properties it calls some parameters uncertain if evidence indeed proves they are so, even though those parameters are often routinely determined in earthquake research. Chapter 10 of the book discusses deep earthquakes region by region where they are known to occur, including also the few deep lunar earthquakes that have been recorded. Although for most of these regions there can hardly be any conclusion on the character of the particular zone of deep seismicity, the information in this chapter is extremely valuable to anyone who is about to study seismicity and/or seismic processes in that region.

Price of the book is considerable, USD 150.00. But taking into the account the fadct that it supplies information comparable to that of a one semester long college course, and howmuch is theper semester fee for a Geophysics course in a good college, the book is worth its price.

Pavel Wiejacz

Institute of Geophysics

Polish Academy of Sciences

Ksiecia Janusza 64

01-452 Warsaw

Poland