Tsunamiites - Features and Implications

Tsunemasa Shiki,Yoshinobu Tsuji,K. Minoura,Teiji Yamazaki

• Editore: Elsevier Science
• Anno: 2011
• ISBN:
  9780080558912
• Argomento: Ciencias físicas
• Categoria: Oceanografía

This book is an overview of the state-of-the art developments in sedimentology of tsunami-induced and tsunami-affected deposits, namely tsunamiites. It also highlights new problems and issues calling for additional investigation, and provides insight into the direction for future tsunamiite researches.

• Provides a comprehensive overview of developments in tsunamiites
• Investigates future trends and development needs
• Cutting edge research articles from leading experts aimed at researchers and scientists

CHAPTER ONE INTRODUCTION: WHY A BOOK ON TSUNAMIITES

T. Shiki^*, K. Minoura^†, Y. Tsuji^‡, T. Yamazaki^§,

^*15-8, Kitabatake Kohata, Uji-city, Kyoto 611-0002, Japan

^†Department of Earth Sciences, Division of Geoenvironmental Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan

^‡Institute of Seismology, University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan

^§2-1-16-1009, Kita-midorigaoka, Toyonaka, Osaka 560-0001, Japan

Key Words

• Tsunamiites, • Tsunami deposits, • Tsunami, • Sediments, • Sedimentology

The purpose of the present volume is to overview the state-of-the art in tsunamiite sedimentology and to point out any problems and subjects that need additional investigation, as well as to provide an insight into the direction and potential for future researches.

Tsunamiite sedimentation has found its way into the area of modern coastal tsunami research so as to provide information about tsunami run-up for use in disaster prevention. In addition, the study of recent tsunami deposits has induced research in tsunami-induced or -related sediments from the geological past. This volume deals with both topics and tries to place them in the framework of the entire field of geosciences.

How terrible the December 2004 Indian Ocean tsunami disaster was! Everybody now realizes the importance of the study of tsunamis and tsunami disasters. The need to study about tsunamiites and the need to publish reports of the recent progress in tsunamiite studies have also been recognized. Most pre-1990 researches on tsunami deposits were focused on the recognition of run-up height, inundation limit and particularly finding recurrent interval times of coastal on-surge tsunamis. Now, however, tsunamiite sedimentology has developed a much wider interest as is demonstrated in this volume.

As stressed by Shiki et al. (2000), catastrophic events as well as various other patterns of time-series changes in nature, including gentle evolution and rhythmic change, are important subjects in the geosciences for understanding the whole truth of natural phenomena and history of the Globe (Earth). In fact, the analysis of tsunamis and their sediments, resulting from meteorite impact, has raised general interest in the past 10 years. Earthquakes and the resulting tsunamis are also remarkable examples of chaotic events that occurred in the geological past, as has been brought into light in the past several years.

It seems that the study of tsunamiites is more difficult than that of other event deposits. Many people want to be informed about criteria for recognizing tsunamiites from the remote geological past and from the prehistoric times. However, such criteria have not yet been established. This is the most important reason for publishing this book.

In this volume, we intend to provide and discuss some instances of new information about how to create a systematic procedure for reading the sedimentary records of tsunamis induced by earthquakes, submarine slide, volcanic eruption and meteorite impact. For the purpose of this discussion, however, general characteristics of tsunamis must first be sufficiently understood. Some important characteristics of tsunamis that cause particular features in tsunami-induced and -reworked sediments are explained first in the chapter presented by Sugawara and others.

Next, several papers follow concerning sedimentary records of onshore and/or inundated inland tsunamis also discussing their significances. Among the contributions, a few report on the sediments generated by the 2004 Indian Ocean tsunami.

Studies of shallow sea tsunami deposits are represented by only a few papers written with the contribution of Fujiwara and Kamataki, but the importance of these studies is emphasized in the review chapters by Shiki and Tachibana and by Keating and others. All the above contributions are primarily concerned with seismic tsunamiites. The significance of studies of bedforms and sedimentary structures in tsunamiites is discussed by Fujiwara. Tsunamis and tsunamiites induced by submarine or coastal slumps are mentioned very briefly in a few contributions. A tsunamiite directly generated by volcanic eruption is dealt with one contribution (by Nishimura) only. However, the Mediterranean homogenites that were induced by the collapse of continental-shelf sediments due to a gigantic volcanic eruption in the Minoan age are examined in two contributions. These sediments provide an interesting example of some special features of deep-sea tsunamiites. Deep-sea tsunami deposits are also dealt in another contribution which reports on the K/T boundary tsunamiite. In addition, there are two more contributions that discuss the K/T boundary meteorite impact-induced tsunamiites.

Several contributions, including a few of the above, discuss and present ideas concerning the characteristic sedimentary records of tsunamis. Dawson and Stwart point out the forgotten important role of offshore current deposition for tsunamiite deposition. Scheffers supplies new information on tsunami-derived boulder deposits. The significance of studies on tsunamiites in the geological past is illustrated in one chapter (by Shiki and Tachibana). Shiki and others describe and discuss the characteristic features of various tsunamiites that are helpful in establishing criteria for distinguishing between the various genetic types of tsunamiites. Finally, the serial papers, the ‘Tsunami Deposits Data Base’ from Hawaii University is kindly presented.

In addition, a bibliography with books, articles and reports on tsunamiites, is presented which can facilitate tsunamiite studies by both students and researchers.

We hope that the information and discussions provided in this volume will help those who wish to answer the question of ‘what are the characteristic sedimentological features of the many kinds of tsunamiites that need to be observed and described’. We also hope that it will encourage new developments in the study of tsunamiites and other event deposits.

We are aware that much more research is needed to significantly increase our understanding of the processes that lead to the formation of various types of tsunamiites in different environments. While browsing through the bibliography on tsunamiites, the readers may get the impression that tsunamiites have neither yet been studied from every possible point of view nor they have been studied in the remote areas of our planet. This holds certainly if the tsunamiite studies are compared with those of turbidites, as described and analysed by Bouma and many others (Bouma, 1962; Bouma and Brouwer, 1964). In addition, our interpretation and discussion may be challenged. The illustrations and discussions provided in this volume should, however, be considered as a stimulus and a starting point for future field and laboratory researches.

This volume was first planned in 2003. Most of the manuscripts were submitted first earlier than the end of 2005. The completion of this volume, however, has caused wear and tear to the editors and some contributors. Many of the manuscripts were revised several times and some were even more times. And it took more than four years to accomplish writing, compiling and editing the manuscripts. Unexpected problems including the ‘university crisis’ in Japan were found to be considerable obstacles to our work. In addition, the terrible December 2004 Indian Ocean tsunami kept editors and some contributors dreadfully busy for a long time.

On the other hand, tsunamiite sedimentology spread widely and made remarkable progress and development during these period. The Indian Ocean tsunami particularly provided a lot of research objects, subjects and new information for tsunamiite sedimentology. Thus, the resulting delay in the publication of this volume should not be seen as a negative aspect only. On the contrary, we actually had more chance and time to obtain and include a lot of new insights, knowledge, and results of discussions in our book. Nevertheless, it is clear that some of the contributors who submitted their views and research results early were victims. We owe them an apology.

Each paper has been critically evaluated by at least two scientists as well as by the editors. Many valuable improvements resulted from their comments. The reviewers are listed below.

K. Chinzei, J. Clague, K. Giles, C. Goldfinger, D. S. Gorsline, C. B. Jaffe, G. Jones, D. King, S. Kiyokawa, F. Kumon, W. Maejima, F. Masuda, H. Okada, G. Prasetya, J. Schnyder, K. Suzuki and R. Walker. Several other reviewers preferred to remain anonymous. In addition, some contributors of this volume were asked to review manuscripts for the volume. We, the editors, would like to thank all those reviewers of the manuscripts whole heartedly.

We are thankful to Hatsuko Shiki, to our colleagues in tsunamiite sedimentology, F. Nanayama, O. Fujiwara, K. Goto, T. Tachibana and to our friends R. Doba, J. Ross, D. Mcmillian for their help and cooperation. We, the volume editors, are greatly indebted to A. J. van Loon, the series editor of Developments in Sedimentology for his ever-abounding enthusiasm in critical reading of the manuscripts and his many helpful suggestions throughout the task. We would also thank F. Wallien, J. Bakker, L. Versteeg-buschman and others of Elsevier Publication Co., for their patience and support.

REFERENCES

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