Geological Records of Tsunamis and Other Extreme Waves

Max Engel, Jessica Pilarczyk, Simon Matthias May, Dominik Brill, Ed Garrett

• Publisher: Elsevier
• Year: 2020
• ISBN:
  9780128156872
• Topic: Physical Sciences
• Subtopic: Geology & Earth Sciences

Geological Records of Tsunamis and Other Extreme Waves provides a systematic compendium with concise chapters on the concept and history of paleotsunami research, sediment types and sediment sources, field methods, sedimentary and geomorphological characteristics, as well as dating and modeling approaches. By contrasting tsunami deposits with those of competing mechanisms in the coastal zone such as storm waves and surges, and by embedding this field of research into the wider context of tsunami science, the book is also relevant to readers interested in paleotempestology, coastal sedimentary environments, or sea-level changes, and coastal hazard management.

The effectiveness of paleotsunami records in coastal hazard-mitigation strategies strongly depends on the appropriate selection of research approaches and methods that are tailored to the site-specific environment and age of the deposits. In addition to summarizing the state-of-the-art in tsunami sedimentology, Geological Records of Tsunamis and Other Extreme Waves guides researchers through establishing an appropriate research design and how to develop reliable records of prehistoric events using field-based and laboratory methods, as well as modeling techniques.

• Features a comprehensive overview of the state of the art in tsunami sedimentology and paleotsunami research
• Offers advice on the most appropriate mapping, sampling, and analytical approaches for a wide variety of coastal settings and sedimentary environments
• Provides methodological details for field sampling and the most important proxy analyses

Section 1

Introduction

Outline

Chapter 1. Geological records of tsunamis and other extreme waves: concepts, applications and a short history of research

Chapter 2. Historical records: their importance in understanding and mitigating tsunamis

Chapter 3. Tsunami magnitude scales

Chapter 4. Trigger mechanisms and hydrodynamics of tsunamis

Chapter 5. Tsunami databases

Chapter 6. Onshore archives of tsunami deposits

Chapter 1: Geological records of tsunamis and other extreme waves: concepts, applications and a short history of research

Max Engel ^{1 , 2} , Simon Matthias May ³ , Jessica Pilarczyk ⁴ , Dominik Brill ³ , and Ed Garrett ^{2 , 5 1} Institute of Geography, Heidelberg University, Heidelberg, Germany ² Geological Survey of Belgium, OD Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium ³ Institute of Geography, University of Cologne, Cologne, Germany ⁴ Department of Earth Sciences, Simon Fraser University, Burnaby, BC, Canada ⁵ Department of Environment and Geography, University of York, York, United Kingdom

Abstract

Increasing population and economic pressures along the world's coastlines have made, and are continuing to make coastal communities more vulnerable to hazards. The hazard management of tsunamis and other extreme waves (storm waves, seiches, infragravity waves) is based on the assessment of the frequency-magnitude relationship of these events, which uses instrumental, historical and, critically for the evaluation of long-term recurrence patterns, geological evidence. The identification of tsunami deposits in coastal sedimentary environments is challenging and has systematically evolved as a subdiscipline of sedimentology only over the last. 30 years (i.e., paleotsunami research). Nevertheless, a wide range of field sampling methods, proxy analyses, and dating approaches have been successfully applied to identify tsunami deposition in different sedimentary environments and infer tsunami impacts in the past. This compendium summarizes the state of the art in paleotsunami research in an effort to provide detailed methodological insights and aims at guiding workflows and site-specific research designs.

Keywords

Coastal hazard assessment; Coastal risk management; Overwash deposits; Paleotsunami research; Paleotempestology; Storm deposits; Tsunami deposits

Introduction

Globally, the coastal realm experiences intense pressures through the growth of population, tourism, and industrial activities, placing an increasing number of humans at risk from hazards associated with the sea and large continental water bodies (Brückner, 2000; Adger et al., 2005; Neumann et al., 2015). These hazards comprise slow-onset hazards, in particular globally rising sea levels and marine pollution, and the rapid-onset hazards of tsunamis, storm surges and storm waves, exceptional infragravity waves or meteotsunamis. The rapid-onset hazards have been significantly exacerbated by global sea-level rise of 15–20 cm over the last 100 years, and they will be further influenced by the 30–100 cm projected for the 21^st century (Church et al., 2013; Rahmstorf, 2017; Li et al., 2018).

Recent tsunamis such as the 2004 Indian Ocean Tsunami and the 2011 Tōhoku Tsunami in Japan and storm surges such as those induced by Cyclone Nargis in Myanmar in 2008 and Typhoon Haiyan in the Philippines in 2013 had dramatic impacts on coastal populations and infrastructure. The exceedingly high number of fatalities and economic losses during these events can largely be explained by an underestimation of the projected site-specific impacts and ineffective or inappropriate coastal-risk management practices. Managing the risk of extreme waves, and in particular tsunamis, which are the focus of this edited compendium, requires a holistic hazard assessment that uses a wide range of information on the local and regional occurrence pattern, i.e., best characterized by its frequency-magnitude relationship. The most accurate type of such information is provided by instrumental data such as tide gauge records (fragmentarily available from c. 1850; much shorter records in most areas), data from satellite altimetry (detection of open-ocean tsunami characteristics, since the 1990s), and post-tsunami surveys (systematic and precise measurements of coastal flooding parameters; fragmentarily available since the 1883 Krakatoa Tsunami; see Chapter 10). Going back in time, the accuracy of measurements decreases during the 19^th century, which is linked to the transition to qualitative and semiquantitative data. This information is usually referred to as historical data and includes newspaper reports, diaries, private letters, ship logs, colonial, church, or government archives, accounting records, or earthquake catalogue (see Chapter 2). Although less accurate, historical data adds important information to the instrumental record, as it extends the time period by a few centuries (e.g., SE Asia, Americas, Africa) to several millennia (e.g., in the Mediterranean; Soloviev et al., 2000). However, similar to tropical cyclones (Corral et al., 2010), frequency-magnitude patterns of tsunamis are described best by inverse power-law functions (Fig. 1.1), although usually without upper truncation (Burroughs and Tebbens, 2005), implying recurrence intervals in the range of 500 (e.g., Jankaew et al., 2008; Brill et al., 2012) or even 800–1000 years (e.g., Minoura et al., 2001; Sawai et al., 2012) for the largest tsunamis along major subduction zones. In many regions, these time scales are not covered by either the instrumental or the historical record. In terms of megatsunamis generated by flank collapses on volcanic islands, recurrence intervals may even exceed several tens of thousands of years (Paris et al., 2018); see Chapter 25.

Sedimentary records of tsunamis surpass this limitation and may enable the reconstruction of frequency-magnitude patterns over multi-centennial and millennial time scales. These time scales cover the largest events, for instance those generated by megathrust earthquakes (e.g., Dawson et...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• About the Editors
• Preface
• Section 1. Introduction
• Section 2. Field methods
• Section 3. Fine-grained deposits
• Section 4. Coarse-clast deposits
• Section 5. Dating
• Subject Index
• Event Index
• Geographic Index