A Hydrodynamics Perspective for the 2004 Megatsunami

The megatsunami of 26 December 2004 was the first tsunami with transoceanic impact since the 1960 Great Chilean and 1964 Great Alaskan tsunamis. Because of the distribution of deaths among a large portion of the nations of the world, the 2004 Boxing Day tsunami is the first universal natural disaster of modern times. For the purpose of adequate mitigation of future tsunamis, it is important to understand which factors control most critically the final characteristics of the flooding, namely runup and inundation. Their successful modeling requires not only a credible database of inundation parameters, against which models can be tested through numerical simulation of the generation, propagation to the local shores, and final interaction of the tsunami with the target beaches, but also in situ observations that help identify unusual impact and previously unrecognized or controversial flow patterns. Here, I comment on the hydrodynamic lessons -mostly relearned- and describe remaining challenges

Late Holocene uplift of Rhodes, Greece: evidence for a large tsunamigenic earthquake and the implications for the tectonics of the eastern Hellenic Trench System

Several large earthquakes in the Hellenic subduction zone have been documented in historical records from around the eastern Mediterranean, but the relative seismic quiescence of the region over the period of instrumental observation means that the exact locations of these earthquakes and their tectonic significance are not known. We present AMS radiocarbon dates from uplifted late Holocene palaeoshorelines from the island of Rhodes, showing that uplift is most consistent with a single large (MW ≥ 7:7) reverse-faulting earthquake between about 2000 BC and 200 BC. Analysis of the uplift treating the earthquake as a dislocation in an elastic half space shows a predominantly a reverse-faulting event with a slip vector oblique to the direction of convergence between Rhodes and Nubia. We suggest that the fault responsible for the uplift dips at an angle of 30-60° above the more gently-dipping oblique subduction interface. The highly oblique convergence across the eastern Hellenic plate boundary zone appears to be partitioned into reverse slip on faults that strike parallel to the boundary and strike-parallel or oblique slip on the subduction interface. Hydrodynamical simulation of tsunami propagation from a range of tectonically plausible sources suggests that earthquakes on the fault uplifting Rhodes represent a significant tsunami hazard for Rhodes and SW Turkey, and also possibly for Cyprus and the Nile Delta.AH is supported by a Shell Studentship. This study forms part of the NERC- and ESRC-funded project "Earthquakes Without Frontiers".This is the final version of the article. It first appeared from Oxford University Press via http://dx.doi.org/10.1093/gji/ggv30

Late Holocene uplift of Rhodes, Greece: evidence for a large tsunamigenic earthquake and the implications for the tectonics of the eastern Hellenic Trench System

Several large earthquakes in the Hellenic subduction zone have been documented in historical records from around the eastern Mediterranean, but the relative seismic quiescence of the region over the period of instrumental observation means that the exact locations of these earthquakes and their tectonic significance are not known. We present AMS radiocarbon dates from uplifted late Holocene palæoshorelines from the island of Rhodes, showing that uplift is most consistent with a single large (MW ≥ 7.7) reverse-faulting earthquake between about 2000 BC and 200 BC. Analysis of the uplift treating the earthquake as a dislocation in an elastic half-space shows a predominantly reverse-faulting event with a slip vector oblique to the direction of convergence between Rhodes and Nubia. We suggest that the fault responsible for the uplift dips at an angle of 30–60° above the more gently dipping oblique subduction interface. The highly oblique convergence across the eastern Hellenic plate boundary zone appears to be partitioned into reverse slip on faults that strike parallel to the boundary and strike-parallel or oblique slip on the subduction interface. Hydrodynamical simulation of tsunami propagation from a range of tectonically plausible sources suggests that earthquakes on the fault uplifting Rhodes represent a significant tsunami hazard for Rhodes and SW Turkey, and also possibly for Cyprus and the Nile Delta

Marine sustainability in an age of changing oceans and seas

The report is the result of fruitful collaboration between EASAC and the JRC. It has been prepared by a working group of experts drawn from the European National Science Academies, which was supported by the JRC. It is hoped that the report will prove useful in the further development and implementation of European Union marine and maritime policy as well as the organisation of supporting science needed to inform and guide these policies. The last ten years have seen a growth in marine and maritime policymaking within the European Union with a key feature being the concept of the ecosystem approach to guide sustainable use of the seas. In view of this increasing focus on coherent marine and maritime policy and governance within the EU, as well as globally, the EASAC Council decided in December 2013 to conduct a study on the issue of marine sustainability. This decision particularly acknowledged the need to provide advice from the point of view of the European science academies on this new direction of marine policy and to highlight the particular challenges that this poses to the organisation of science. The report has the aim of contributing to the governance challenge of how to integrate the various aspects of marine policy (fisheries management, biodiversity conservation and marine environmental protection) as part of a coherent ecosystem approach. It considers how current science knowledge on marine ecosystems and the organisation of science can support an integrated approach to management of the seas. The report looks at a number of key aspects for sustainable development in changing oceans and seas, and particularly highlights the key scientific challenges in addressing these issues. The report presents both recommendations from science for policy development, and recommendations on policy for science. The health of the oceans and coastal seas is vital for the future well-being of all of Europe, indeed of entire mankind, and sustainable management of this sensitive and fast changing component of the global ecosystem is essential.JRC.A.3-Inter-institutional, International Relations and Outreac

The Fukushima accident was preventable

The 11 March 2011 tsunami was probably the fourth largest in the past 100 years and killed over 15 000 people. The magnitude of the design tsunami triggering earthquake affecting this region of Japan had been grossly underestimated, and the tsunami hit the Fukushima Dai-ichi nuclear power plant (NPP), causing the third most severe accident in an NPP ever. Interestingly, while the Onagawa NPP was also hit by a tsunami of approximately the same height as Dai-ichi, it survived the event 'remarkably undamaged'. We explain what has been referred to as the cascade of engineering and regulatory failures that led to the Fukushima disaster. One, insufficient attention had been given to evidence of large tsunamis inundating the region earlier, to Japanese research suggestive that large earthquakes could occur anywhere along a subduction zone, and to new research on mega-thrusts since Boxing Day 2004. Two, there were unexplainably different design conditions for NPPs at close distances from each other. Three, the hazard analysis to calculate the maximum probable tsunami at Dai-ichi appeared to have had methodological mistakes, which almost nobody experienced in tsunami engineering would have made. Four, there were substantial inadequacies in the Japan nuclear regulatory structure. The Fukushima accident was preventable, if international best practices and standards had been followed, if there had been international reviews, and had common sense prevailed in the interpretation of preexisting geological and hydrodynamic findings. Formal standards are needed for evaluating the tsunami vulnerability of NPPs, for specific training of engineers and scientists who perform tsunami computations for emergency preparedness or critical facilities, as well as for regulators who review safety studies