The seismicity of Egypt, Arabia, and the Red Sea

orites, siliceous rocks, phosphorites and carbonaceous rocks. The Atlas des Roches Skdimentaires constitutes an excellent working tool for PhD students and researchers who want to accurately identify the microfacies of the uncredibly various sedimentary rocks, and use them in order to characterize the sedimentary and diagenetic environments. 217 high-quality color photographs are provided and precisely commented. The presentation is clear and didactic, permitting a daily use in the laboratory. Although comprising essentially english examples, the choice of the photographs is perfectly adequate, the comments are detailed and cover the different aspects of a given thin section: texture, structure, particle size, mineral and organic components, cements, other optical characteristics, sedimentary and diagenetic implications, insertion of the different rocks described within the classification of the sedimentary rocks. A few appendices provide information on the technical ways classically used to prepare high-quality thin sections of sedimentary rocks and to apply some special treatments to the recognition of carbonate microfacies. To summarize the Atlas des Roches Skdimentaires offers to the french-reading students and researcher an excellent opportunity to understand the significance of sedimentary rocks from their multiple characters investigated under the microscope. H. Charnley, Villeneuve d’Ascq SSDI 0012-8252(95)00034-S

Seismology

N.N. Ambraseys, C.P. Melville and R.D. Adams, 1994. The Seismic& of Egypt, Arabia, and the Red Sea. Cambridge Univ. Press, U.K. xix + 181 pp. Price: & 60.00. ISBN o-521-39120-2 This book evolved from a research project of the Civil Engineering Department of the Imperial College, London on the “seismicity of Saudi Ara-

bia and adjacent areas”. Since large parts of Saudi Arabia are almost aseismic the region was broadened considerably and covers now a wide area centred in the Red Sea including Libya, Egypt, Sudan, Ethiopia, Jemen, Saudi Arabia with Hejaz, Persian Gulf, Southern Iraq, Dead Sea Region, Sinai, Eastern Mediterranian. It contains documented events from the earliest history up to 1983, but is also updated to 1992 for some important events. The book can geographically be considered complementary to the very comprehensive volume on A History of Persian Earthquakes by Ambraseys and Melville published in 1982 by Cambridge University Press. According to the authors the present book is less ambitious concerning completeness but was much more difficult to compile because of the large numbers of sources from different cultural environments, histories, languages and calendars. It was the chief objective of the authors to critically check the reliability of the data and to avoid multiple entries of the same events in the catalogues. It was therefore necessary for them to go back to the original sources. Critical analysis of the historical but also of the instrumental evidence made it possible to discover false reports and resolving conflicting information. It is perhaps unique and shows a high degree of care and responsibility that unidentified and false or mislocated events are described individually in a special catalogue together with the respective argumentation. All those who have been involved in seismic hazard assessment know how severe the results may depend on the reality and reliability of even a single event. By discussing the methodical background of hunting for historical earthquakes the authors display a fascinating story which goes deep into many aspects of the cultural history of the different countries. Obviously the uniform translation from different languages of the Arabic World in different centuries requires high expertise and decisions to be made. A particular problem which is far from the usual comprehension of a seismologist is the chronology. The Muslim calendar begins 620 AD and has 354 days per year. The day begins at sunset. There are two Muslim calendars, a Coptic calendar in Egypt and Ethiopia

Book Reviews

and there are the Julian and Gregorian Christian calendars. In the present catalogue all earthquakes are dated according to the Julian calendar up to 1582 and to the Gregorian calendar thereafter. The main part of the book are, of course, the earthquake catalogues. A descriptive catalogue of 184 BC-AD 1899 contains in chronologic order 245 events with a narrative but condensed description of observed effects. This catalogue is followed by a listing of the same earthquakes where it has been attempted to assign to each event the most reasonable epicenter coordinates and focal time, quality characteristics, intensity classes (related to MSK), associated phenomena such as tsunamies etc., and in some cases estimates of macroseismic magnitudes. Almost one thousand events, mainly based on instrumental data are, after description of the methods, listed in a catalogue of 1899 to 1992 which contains, in addition to location and time, MS, m, and, if possible, the epicentral intensity. The book closes with statistical considerations on the completeness of the data and apparent time variations of seismicity which, in part, finds its explanation in population geography, cultural rises and declines, religions and political situation. The authors deserve highest appreciation for having carried out this difficult and time consuming work. The book will certainly be an indispensible source of information for seismologists and urban planners but also for historical studies in which natural catastrophies may play a role. The book should not only be available in libraries of seismological institutes but also in historical libraries and those of national and international authorities concerned with natural hazards. H. Berckhemer,

Frankfurt

SSDI 0012-8252(95)00035-6

Fractals C.C. Barton and P.R. La Pointe (Editors), 1995. Fractals in Petroleum Geology and Earth Pro-

273

cesses. Plenum, New York. Hardcover. xxiii + 317 pp. Price: $85.00. ISBN o-306-44868-8 I am often asked the question: “What are fractals really good for?” In the future I will refer the questioner to this volume. The papers in this volume present excellent examples of how fractal concepts are extremely useful in petroleum exploration. The volume opens up with an extremely interesting paper by Benoit Mandelbrot on the application of fractal statistics to distributions of natural resources and other applications. This paper is an updated version of his 1962 IBM Research Note that had never been published in the open literature. One of the major controversies in terms of geostatistics is the relative applicability of fractal (power-law or Poreto) statistics versus log-normal statistics. Mandelbrot addresses this question directly. The second paper by Chris Barton and Chris Scholz applies fractal statistics to the sizefrequency distribution of oil fields and the spatial distribution of hydrocarbons. It is generally accepted that earthquakes obey the fractal relation N mADI where N is the number of earthquakes with a rupture area greater than A and D is the fractal dimension; this is one form of the Guttenberg-Richter frequency-magnitude relation for earthquakes. These authors argue that fractal statistics are also applicable to petroleum reserve estimation; the fractal relation N _ VD13 is applicable where N is the number of oil fields with a volume of oil greater than V, they argue that any estimates of undiscovered petroleum reserves should be based on fractal statistics. These authors also apply fractal statistics to the spatial distribution of petroleum. They divided the Denver basin and the Powder River basin into a series of square regions of size r. They then relate the number of these regions in which there are producing and showing wells N to the size of the region r by the fractal relation N N rD. They find D = 1.43 for the Denver basin and D = 1.49 for the Powder River basin. This is the well known box counting technique for determining the fractal dimension of a distribution. These authors also apply this technique to all