Advances in Geophysics (eBook)

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2009 | 1. Auflage
192 Seiten
Elsevier Science (Verlag)
978-0-08-095700-5 (ISBN)

Infos

The critically acclaimed serialized review journal for over 50 years, Advances in Geophysics is a highly respected publication in the field of geophysics. Since 1952, each volume has been eagerly awaited, frequently consulted, and praised by researchers and reviewers alike. Now in itsÿ51st volume, it contains much material still relevant today--truly an essential publication for researchers in all fields of geophysics.

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The critically acclaimed serialized review journal for over 50 years, Advances in Geophysics is a highly respected publication in the field of geophysics. Since 1952, each volume has been eagerly awaited, frequently consulted, and praised by researchers and reviewers alike. Now in its 51st volume, it contains much material still relevant today--truly an essential publication for researchers in all fields of geophysics.

Inhalt

Front cover 1
Half title page 2
Title page 4
Copyright page 5
Contents 6
Contributors 8
Chapter 1. Seismicity Induced by Mining: Recent Research 10
1. Introduction 10
2. Seismic Monitoring 12
3. Mining Operations and Seismicity 24
4. Source Mechanisms 31
5. Source Time Function 36
6. Source Parameters and Their Scaling Relations 41
7. Precursory Phenomena and Prediction of Large Seismic Events 49
8. Summary 52
Acknowledgments 54
References 54
Chapter 2. Induced Seismicity in Hydrocarbon Fields 64
1. Introduction 64
2. Case Studies, Common Observations and Regional Occurrence 66
3. Seismic Monitoring 78
4. Seismicity Induced by Fluid Injection 82
5. Seismicity Induced by Fluid Extraction 87
6. The Controversy Surrounding Major Midcrustal Earthquakes 96
7. Conclusions and Outlook 103
Acknowledgments 109
References 109
Chapter 3. Phenomenology of Tsunamis: Statistical Properties from Generation to Runup 116
1. Introduction 116
2. General Description of Tsunami Generation Physics 118
3. Near-field Regimes: Broadside and Oblique 129
4. Far-field Regime 147
5. Summary and Discussion 165
Acknowledgments 167
References 168
Index 180

Textauszug

Seismicity Induced by Mining: Recent Research

Slawomir J. Gibowicz

Institute of Geophysics, Polish Academy of Sciences, Ul. Ks. Janusza 64, 01-452 Warsaw, Poland

Abstract

The present review of seismicity induced by mining is a continuation of the previous reviews, published in 1990 and 2001 in Advances in Geophysics, describing the problems involved and the state-of-the-art of relevant research in this field at the end of 1980s and 1990s. During the last decade, seismic monitoring has been expanded in several mining districts, a number of new techniques have been introduced, and new significant results have been obtained in studies of seismic events induced by mining. This review is organized similarly to some extent to the previous ones. New techniques in seismic monitoring in mines, mining factors affecting seismicity, source mechanisms and source time functions, source parameters and their scaling relations are briefly discussed. Precursory phenomena observed in mines and some attempts at prediction of larger events are reviewed. The new results obtained so far by the Japanese research group in South African gold mines, the concepts of stress diffusion and of “critical earthquakes” applied to seismicity in mines, and numerical modeling of rock mass response to mining are also briefly discussed.

Key Words: Induced seismicity; Seismicity induced by mining; Seismic monitoring in mines; Seismic source mechanisms; Source time function; Source parameters; Seismic scaling relation in mines; Precursory phenomena in mines

1. Introduction

In the previous reviews of seismicity induced by mining (Gibowicz, 1990 and Gibowicz and Lasocki, 2001), the general description of the problems involved and the state-of-the-art of relevant research in this field at the end of 1980s and 1990s, respectively, was given. During the last eight years, seismic monitoring has been expanded in several mining districts, especially in Australia, Russia and China, a number of new techniques have been introduced, and new significant results have been obtained in studies of seismic events induced by mining. I was invited therefore once again by Dr. Renata Dmowska, coeditor of Advances in Geophysics, to contribute a new review, describing in some detail the latest achievements in the field.

The first International Symposium on Rockbursts and Seismicity in Mines (RaSiM) held in Johannesburg, South Africa, in 1982 was followed by the second Symposium held in Minneapolis, Minnesota, in 1988, the third Symposium held in Kingston, Ontario, in 1993, the fourth Symposium held in Krakow, Poland, in 1997, the fifth Symposium held again in South Africa in 2001, and by the sixth Symposium held in Perth, Western Australia, in 2005. The proceedings of these last two symposia (van Aswegen et al., 2001 and Potvin and Hudyma, 2005) contain some 160 technical papers on the subject, written by experts from over 15 countries. The RaSiM symposia helped us to understand some fundamental ideas about the nature and causes of seismic events in mines. Most important is the recognition that seismicity is the response of the rock mass to stress and strain changes induced by mining, implying that the mine design can influence the level of seismicity. A review of the RaSiM meetings’ contribution to the understanding and control of mine seismicity has been published by Ortlepp (2005).

Over the last eight years, a book and a special issue of Pure and Applied Geophysics devoted entirely to induced seismicity in a very broad sense have been published. The book, Induced Earthquakes by Guha, published in 2000 (Guha, 2000), covers a very wide range of man-made and natural phenomena defined by the author as induced earthquakes, ranging from seismicity induced by water reservoirs and fluid injection into deep wells to underground nuclear explosions and tidal stresses. Seismicity induced by mining is described in a separate chapter that contains interesting information, especially that related to seismicity in the Kolar gold fields of India. The special issue of Pure and Applied Geophysics, edited by Trifu, was published in 2002 (Trifu, 2002) and reprinted as a separate topic volume. This volume also covers a very wide range of topics, from mining-induced seismicity to geotechnical applications, from the monitoring of petroleum reservoirs to fluid injections in geothermal areas, and to seismicity associated with water reservoirs. Seven contributions are related to seismicity induced by mining or associated with the presence of mines. A third book, Seismogenic Process Monitoring, which is partly devoted to induced seismicity and covers several topics related to seismicity induced by mining, was published in 2002 (Ogasawara et al., 2002a). The book was edited by Ogasawara, Yanagidani and Ando, and presents the outcome of a Joint Japan-Poland Symposium on Mining and Experimental Seismology held in Kyoto in November 1999. It contains 29 papers divided into four parts. The first part, called the near-source monitoring, is composed of 14 contributions, all but one related to seismicity induced by mining in Poland (8 papers) and in South Africa (5 papers).

Two large seismic research projects have been carried out on an unprecedented scale for several years in gold mines in South Africa. Firstly, from 1993 the research on rockbursts and seismicity there is coordinated by the Safety in Mines Research Advisory Committee (SIMRAC). The scope of 94 projects supported by SIMRAC up to 2000 covers assessment of seismic issues, fundamental research into seismic prediction and possible prevention of large events, determination of criteria for mine design to reduce seismicity and rockburst damage, transfer of new technology into the mining industry, and others. Before 1993, rockbursts were either the single greatest or the second-greatest contributor to the fatality rate from accidents in gold mine, while between 1994 and 2000 the fatality rate decreased to half, though it is acknowledged that the SIMRAC research could be just one of the many factors that have contributed to the fatality decline (Adams and van der Heever, 2001).

Secondly, the Japanese research group has initiated semi-controlled seismogenic experiments in South African deep gold mines, where mining takes place at depths of 2000-3600 m, inducing seismic events in the close vicinity of stopes. Thus seismogenic processes can be monitored at very short distances with sensors installed in seismogenic areas. The first experimental field without dykes and faults was established in 1996 at a depth of 2700 m at a mine near Carletonville, in cooperation with the ISS International, where the pilot, first and second experimental phases were carried out (Ogasawara et al., 2001). They have monitored more than 20,000 seismic events with borehole triaxial accelerometers, using a data acquisition system with 15 kHz sampling and a 120 dB dynamic range. Later several experimental fields was established in other mines, one of them near a strong dyke at a depth of 1700 m, and in 2000 the Japanese research group began continuous monitoring of normal and shear strains on a fault, where larger events were expected (Ogasawara et al., 2002b).

This review is organized similarly to some extent to the previous ones. New techniques in seismic monitoring in mines, mining factors affecting seismicity, source mechanisms and source time functions, source parameters and their scaling relations are briefly discussed. Statistical methods and seismic hazard assessment in mines are only touched upon; they were described in some detail in the previous review (Gibowicz and Lasocki, 2001). The other topic not discussed here is the seismic discrimination between underground explosions and seismic events originating in deep mines. Large seismic events in mines are of interest to seismologists monitoring compliance with the Comprehensive Test Ban Treaty (CTBT) prohibiting nuclear explosion testing. There are a few new results related to this topic that have been recently published (see, e.g. Baumgardt and Leith, 2001, Bowers and Walter, 2002, Koch, 2002, Roth and Bungum, 2003 and Goforth et al., 2006).

Precursory phenomena observed in mines and some attempts at prediction of larger events are briefly reviewed. The new results obtained so far by the Japanese research group in South African gold mines, the concepts of stress diffusion and of “critical earthquakes” applied to seismicity in mines and numerical modeling of rock mass response to mining are briefly discussed.

2. Seismic Monitoring

Seismicity induced by mining is commonly described as the occurrence of earthquakes caused by rock failures, a result of stress changes in the rock mass near mining excavations. Mining-induced events are caused by increases in the shear stress or decreases in the normal stress acting on the fault planes. Seismic events therefore are induced only in those regions where the ambient stress has been modified substantially by the mine excavations. It is well known that seismic monitoring can provide direct observations related to the occurrence of local instabilities in the rock mass, but a better understanding of the mechanism of induced seismicity is needed to achieve the desired level of control. Deep mines provide unique natural laboratories for studies of seismic source processes and fault properties. The...

Produkt-Details

• Erscheint lt. Verlag: 19.11.2009
• Mitarbeit: Herausgeber (Serie): Renata Dmowska
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Geowissenschaften ► Geologie
• Themenwelt: Naturwissenschaften ► Geowissenschaften ► Geophysik
• Themenwelt: Naturwissenschaften ► Physik / Astronomie
• Themenwelt: Technik
• ISBN-10: 0-08-095700-5 / 0080957005
• ISBN-13: 978-0-08-095700-5 / 9780080957005