Characterization of Modern and Historical Seismic–Tsunamic Events, and Their Global–Societal Impacts

Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021 Characterization of modern and historical seismic– tsunamic events and their global–societal impacts Yildirim Dilek1*, Yujiro Ogawa2 and Yasukuni Okubo3 1Department of Geology and Environmental Earth Science, Miami University, Oxford, OH 45056, USA 2Institute of Geoscience, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan 3Japan Space Systems, 3-5-8 Shibakoen, Minato-ku, Tokyo 105-0011, Japan YD, 0000-0003-2387-9575 *Correspondence: [email protected] Abstract: Earthquakes and tsunamis are high-impact geohazard events that can be extremely destructive when they occur at large magnitudes and intensities, although their causes and potential locations are, for the most part, predictable within the framework of plate tectonics. Amongst the main reasons for their high impact include enormous numbers of casualties, extensive property damage in vast areas and significant social and economic disruption in urban settings where populous residential areas, global banking centres, industrial factories and critical facilities (nuclear power plants, dams) may be located. In order to reduce the impact of these geohazards, nations, societies, professional organizations and governments need to collaborate to prepare more effective seismic and tsunami risk assessments, disaster management plans, educational and training programmes for increased preparedness of the public, and strategic plans and objectives for capacity building, skill and knowledge transfer, and building of societal resilience. Improved building design and construction codes and emergency preparedness and evacuation plans should be part of disaster management plans in countries where destructive earthquakes and tsunamis have occurred. The rapid increases in population along coastal corridors in developing and developed countries is likely to escalate the social and economic impacts of these geohazards exponentially in the future. The chapters in this book present case studies of some of the most salient earthquake and tsunami events in historical and modern times, their origins and manifestations, and efforts and the most effective practices of risk assessment and disaster management implemented by various governments, international organizations and inter-governmental agencies following these events. New methods of comput- ing probabilistic seismic hazard risks, delineating respect distance and damage zones along and across seismically active faults and recognizing tsunamigenic and submarine landslides on the seafloor are introduced. The conclusions presented in the chapters show that: (1) scientific understanding of the characteristics of seismically active faults is paramount; (2) increased local (community), national and global resilience is necessary to empower societal preparedness for earthquake and tsunami events; and, (3) all stakeholders, including policy-makers, scientists, local, state and national governments, media and world organizations (UNESCO, IUGS, GeoHazards International, Global Geodetic Observing System, National Earthquake Hazards Reduction Program) must work together to disseminate accurate and timely information on geohazards, to develop effective legislation for risk reduction and to prepare realistic and practical hazard mitigation and management measures. Geohazards are the manifestations of geological and of such catastrophic geohazard events that we wit- environmental conditions caused by short-term and nessed in the Indian Ocean earthquake and tsunami long-term earth processes, and commonly result in in Indonesia (December 2004), on the Tohoku catastrophic damage, casualties and destruction of coast, Japan (March 2011, Tohoku-oki Earthquake social infrastructure (Figure 1; McGuire et al. and Great Tsunami), in Italy (August 2014), in 2000). Earthquakes and tsunamis are two of the Nepal (April 2015, the Gorkha Earthquake) and in most devastating geohazards (Table 1; Bolt 2004; Sulawesi–Indonesia (September 2018) are some of de Boer and Sanders 2005; Guidoboni and Ebel the most salient reminders of how devastating and 2009; Plag 2014; Scourse et al. 2018) because they destabilizing the manifestations of these natural are generally linked in space and time and they com- disasters can be (Plag 2014). History also reminds monly occur along the most densely populated us that the demise of some of the most important civ- coastal corridors and industrial centres of continents ilization centres in the world was accelerated and (e.g. Pacific Rim) and countries (e.g. those around completed by major earthquakes, tsunamis, volcanic the Aegean and Mediterranean seas). The examples eruptions and floods/droughts (McGuire et al. 2000; From: Dilek, Y., Ogawa, Y. and Okubo, Y. (eds) Characterization of Modern and Historical Seismic–Tsunamic Events, and Their Global–Societal Impacts. Geological Society, London, Special Publications, 501, https://doi.org/10.1144/SP501-2021-17 © 2021 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/). Published by The Geological Society of London. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics Downloaded from http://sp.lyellcollection.org/ by guest on September 25, 2021 Y. Dilek et al. (a)(b) Figure 1. (a) Occurrences of major geohazard types between 1980 and 2010, and (b) their cost to the global economy in billions of US Dollars during this period (New Scientist 2020). Major geohazards types are grouped under four categories: earthquakes, tsunamis and volcanic activities (Category 1), which are strictly originated from geological processes, commonly occurred around 100 times or less per year in the 30-year period. On the other hand, extreme temperatures, droughts and fires (Category 2), floods, mass water movements (Category 3), and storms (Category 3) display steadily increasing patterns of their occurrence (.100, .300 and .400 per year, respectively) during the same period. The histograms in 1A show that the economic cost of extreme temperatures, fires and droughts has nearly remained the same; however, but floods and storms cost the global economy more nowadays than they did thirty years ago. These patterns of rising numbers of natural hazard events reflect the increasing effects of global warming, increased greenhouse emissions, and rising ocean water temperatures during the past 30 years. Similarly, the economic losses that are associated with all these natural hazards are also becoming costlier, as the diagram in Figure 1b shows. Of all the natural hazard categories, earthquakes (and associated tsunami events) were the costliest to the global economy as in the cases of the 1995 Kobe (Mw = 6.9 and US$220 Billion) and the 2011 Tohoku-oki (Mw = 9.0 and US$365 Billion) earthquakes, even though the yearly occurrence numbers of earthquakes and tsunamis remain stable. The data and modified graphs are from NewScientist (2012). Dilek 2017). Their impacts on local and global econ- regulators and administrators of some professional omies, on the stability of nations and societies and on organizations to talk to each other and find effective world geopolitics are immense (Stein and Mazzotti ways to raise public awareness of geohazard risks. 2007). The first scientific session was part of the Japan Geo- Despite all this knowledge, educational and sci- science Union–American Geophysical Union Joint entific research programmes dealing with risk assess- Meeting, held in Makuhari Messe, Chiba, Japan, ment, prediction and mitigation and management on 25 May 2017. The Session H-DS11 was entitled: still remain elusive for most nations and organiza- ‘Enhancing Scientific and Societal Understanding of tions. There is also a strong need for better awareness Geohazards in an Engaged Global Community’. The of the existence of geohazards (where and why they other meeting took place at an international confer- occur) and their role in the lives and functions of ence on Resources for Future Generations 2018 future generations, developing nations and develop- (RFG 2018), held in Vancouver, Canada, during ing economies. Therefore, informed and systematic the week of 16–21 June, 2018. The related session efforts for global geohazard safety through education was entitled ‘EA1: Convergent Margin Geohazards and training, risk assessment, preparedness and mit- and Geodisasters: Present Understanding, Mitiga- igation–management are much needed. To this end, tion, and Long- and Short-term Preparedness’. we have convened two large meetings on global geo- Both sessions were well attended and the discussions hazards during the last four years, bringing together pertaining to geohazard risk assessment techniques groups of geoscientists, policy makers, government and efforts in different countries were particularly Downloaded from Table 1. Types, the natural causes, the dates and locations, and the social, economic and political consequences of the top ten geohazard occurrences in history. The ranking is based on the magnitude and intensity of earthquakes, the number of fatalities, and the extent of economic losses (data from Pappas and Means 2020, and this study). Ranking Geohazard Geohazard Date Geographic Location Natural Cause Social, Economic & Political Consequences Among the Top Category Event 10 3 Earthquake Shaanxi Eq 23 January Shaanxi Province, Wei Slip along the Weihe Basin Deadliest earthquake in the recorded human history. 1556 River Valley, China

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