Ellis / Sherman Coastal and Marine Hazards, Risks, and Disasters

1. Auflage 2014
ISBN: 978-0-12-396538-7
Verlag: William Andrew Publishing
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 592 Seiten, Format (B × H): 152 mm x 229 mm

Sea and Ocean Hazards, Risks and Disasters provides a scientific approach to those hazards and disasters related to the Earth's coasts and oceans. This is the first book to integrate scientific, social, and economic issues related to disasters such as hazard identification, risk analysis, and planning, relevant hazard process mechanics, discussions of preparedness, response, and recovery, and the economics of loss and remediation. Throughout the book cases studies are presented of historically relevant hazards and disasters as well as the many recent catastrophes. 

- Contains contributions from experts in the field selected by a world-renowned editorial board
- Cutting-edge discussion of natural hazard topics that affect the lives and livelihoods of millions of humans worldwide
- Numerous full-color tables, GIS maps, diagrams, illustrations, and photographs of hazardous processes in action will be included

Zielgruppe

<p>Ocean, coastal, and atmospheric scientists; geologists and hydrologists</p>

Autoren/Hrsg.

Ellis, Jean

Sherman, Douglas J.

Weitere Mitwirkende

Shroder, John F.

Fachgebiete

• Geowissenschaften Geographie | Raumplanung Deltas, Flussmündungen, Küstenregionen
• Geowissenschaften Umweltwissenschaften Soziale & wirtschaftliche Auswirkungen von Umweltfaktoren
• Geowissenschaften Umweltwissenschaften Naturgewalten & Katastrophen
• Geowissenschaften Umweltwissenschaften Umweltmanagement, Umweltökonomie
• Geowissenschaften Geologie Marine Geologie, Ozeanographie (Meereskunde)

Inhaltsverzeichnis

1. Introduction to coastal and marine hazards and disasters 2. Generation, characteristics, and dynamics of tsunami 3. Paleo-tsunami 4. Tsunami warning and mitigation 5. Tsunami case studies 6. Generation, characteristics, dynamics, and modeling storm surge 7. Paleo-storm surge 8. Storm surge warning and mitigation 9. Storm surge case studies 10. Sea level rise scenarios and causes 11. Adapting to sea level rise 12. Mitigating coastal change 13. Shoreline change case studies 14. Extreme waves 15. Rip currents/undertow 16. Sea ice 17. Threats to mangrove resources and mitigation 18. Threats to coral resources and mitigation 19. Threats to marsh resources and mitigation 20. HABs

Leseproben

Chapter 2

Tsunami Dynamics, Forecasting, and Mitigation

Utku Kânoglu1,  and Costas Synolakis2,3     1Department of Engineering Sciences, Middle East Technical University, Ankara, Turkey     2Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA     3Technical University of Crete, Chania, Greece

Abstract

Tsunamis had been earlier believed as extremely rare events, yet about one event per year has been reported in the past two decades, making them a more common extreme hazard. After the 2004 Indian Ocean tsunami, the need for substantial improvements in tsunami real-time and long-term forecasting capabilities, education, and development of tsunami-resilient communities became evident. Thereafter, there were substantial advances in tsunami science, i.e., significant advancements in warning methodologies, predisaster preparedness, and basic understanding of related phenomena. The 2011 Japan tsunami, broadcasted live to a stunned world audience, underscored the difficulties of implementing theoretical advances in applied hazard mitigation. Japan is possibly the most tsunami-ready nation on the Earth. Nonetheless, the size of the 2011 earthquake was largely unexpected and, in many instances, the floods penetrated several times the distances that had been anticipated in pre-event planning. Three years later, Japan is still recovering. A need exists for acquainting the broader scientific community on advances in prediction and mitigation in hopes that applied disaster preparedness improves.

Keywords

Forecasting; Inundation; Mitigation; Runup; Tsunami; Tsunamograph

2.1. Introduction

After the December 26, 2004, Indian Ocean (Boxing Day) tsunami, Huppert and Sparks (2006) wrote “It is likely that in the future, we will experience several disasters per year that kill more than 10,000 people.” Their assessment was not far off, unfortunately, to wit the March 11, 2011, Japan tsunami (the Great East Japan Earthquake Disaster) that alone resulted in more than 20,000 casualties. Tsunamis and other coastal disasters have killed over 200,000 since Boxing Day 2004. Coastal communities are now extensively developed centers of substantial commercial activities that are also at risk.

Tens of millions of people live in high-risk coastal communities around the world, and hundreds of thousands of tourists are at high-risk beaches at any given time. This appears yet another case of what Jackson (2006) has called fatal attraction; earthquakes occur in places where they would likely cause more casualties compared to earlier times because in some places the availability of water is linked to underlying faults and because many rural communities have grown much larger with mostly poor building standards.

Furthermore, geological hazards such as tsunamis are not only threats to the countries in whose territories they originate but also can cause wide-scale devastation across national boundaries, as dramatically shown during the 2004 Boxing Day tsunami which impacted at least 16 countries directly and tourists from many other countries (Synolakis and Kong, 2006). Among the casualties during the 2004 disaster were 428 Swedish people, out of a population of about 10million.

The word tsunami made its grand debut in most world languages with the December 26, 2004 event. Yet the first historical inference of coastal inundation by tsunamis refers to the eruption of the Thera volcano in the Eastern Mediterranean (Marinatos, 1939), now believed to have occurred around 1620BC. This precipitated the demise of the Minoans in Crete Island (Bruins et al., 2008). Referred to as tidal wave in English, the exact translation of tsunami from the Japanese is harbor wave. Probably, early observations of these unusual waves by eyewitnesses were in ports, as harbors were centers of commercial activity and the points of contact with the sea. In Japan, where historic records exist since the ninth century AD, these motions were often associated with tsunamis, hence the name. It is not uncommon that a relatively small tsunami entering a port or harbor can trigger substantial water level oscillations and reach substantial heights, and water motions can persist for hours, as most recently observed in many harbors along the Japanese coast, as well harbors in the Pacific coast of the United States after the 2011 Japan tsunami (Figure 2.1).

Tsunamis are generated by impulsive geophysical events of the seafloor and of the coastline, such as earthquakes and submarine and subaerial landslides. Volcanic eruptions and asteroid impacts are less common but more spectacular tsunami-generation mechanisms (Gisler, 2009; Morrison, 2006). Tsunamis are high-impact, long-duration disasters and often entail substantial human drama, as outlined in the Hollywood movie The Impossible. They are long waves with small steepness and evolve substantially, through spatial and temporal spreading from their source region, as suggested in the map of energy propagation of the Boxing Day tsunami (Titov et al., 2005a) (Figure 2.2); also see Figure 2.3 for the March 11, 2011, tsunami (Tang et al., 2012).

The determination of the terminal effects of tsunamis as they strike shorelines and coastal structures remains one of the quintessential problems in tsunami hazard mitigation. Since the Boxing Day tsunami, a new science of tsunami forecasting has emerged (Bernard and Robinson, 2009). The first extensively tested real-time forecasting methodology is now officially in use by tsunami warning centers (Vasily Titov, personal communication, June 8, 2013) and is rapidly becoming web-based (Burger et al., 2013). This technology is based on real-time data assimilation from measurements from tsunamographs: deep-ocean buoys also known as DARTs (Tang et al., 2012; Wei et al., 2008). Measurements from tsunamographs are used to better define the seafloor displacement that triggered the tsunami. Such hydrodynamic inversions are now as standard as seismic inversions. New markers have emerged that help to identify paleotsunamis and thus better infer the mechanisms of paleoearthquakes. High-end computational tools now allow for inundation predictions, even from submarine landslides. New analytical results help explain the scaling of vexing tsunami evolution problems. Most coastlines of highly developed nations along the Pacific now have inundation maps for pre-event planning (see section 2.4.1), as do at-high-risk cities in Indonesia, such as Padang. Several communities, including several in the United States, have earned the coveted tsunami-ready designation. With the exception of the Mediterranean, all the at-risk world oceans and seas are now covered with rapid warning procedures.

FIGURE 2.1 Significant tsunami currents were observed in many harbors during the March 11, 2011, tsunami. (Top left) View of whirlpool at Port of Oarai, Japan, taken from helicopter approximately at 17:54 (local time), i.e., 3h 8min after the earthquake; (bottom left) numerical results of Lynett et al. (2012) for the fluid speed of the tsunami in the Port of Oarai; after the 2011 Japan tsunami (top right) surge jetting in to the inner harbor of Crescent City, California; and (bottom right) Pillar Point Harbor, south of San Francisco, which experienced counterrotating eddies in the inner and outer basins. After Lynett et al. (2012).

FIGURE 2.2 Global maximum tsunami heights of the Boxing Day tsunami computed from numerical model of Method of Splitting Tsunami (MOST) (Titov and González, 1997), after 44h of propagation. Inset shows distribution of the slip among four subfaults (from south to north: 21 m, 13 m, 17 m, and 2 m) which provides best fit for satellite altimetry data and correlates well with seismic and geodetic data inversions, and the computed wave heights in the Bay of Bengal. Wave amplitudes, directionality, and global propagation patterns appear primarily determined by the orientation and intensity of the offshore seismic line source and subsequently by the trapping effect of midocean ridge topographic waveguides. Contours show computed tsunami travel times. Circles denote the selected tide gauge stations where amplitudes of tsunami are given in three range categories. After Titov et al. (2005a).

FIGURE 2.3 (Top) Deep-ocean Assessment and Reporting of Tsunamis (DART) measurements used by the United States National Oceanic and Atmospheric and Administration (NOAA) Center for Tsunami Research (NCTR) for the inversion of the March 11, 2011, Japan tsunami and the resulting waveforms at DARTs after the inversion. (Middle) Global maximum wave amplitudes for the source identified by the NCTR in real time. Inset shows the resultant unit sources. After Tang et al. (2012). (Bottom left) Initial tsunami source defined by the NCTR in real time for the event. Comparison of computed tsunami maximum wave amplitudes on land based on (bottom center) tsunami source constrained from DART measurements and (bottom right) the US Geological Survey (USGS) finite fault model source with measured tsunami heights and runup values (black lines, red dots, and blue...

Über Autor(innen)

Shroder, John F.
[e-mail]