Tsunami warning traditionally has been perceived within the scientific community as an essentially deterministic process. This may be satisfactory in regions where tsunami monitoring is very extensive and the uncertainty in tsunami forecasting is low. However, where there is significant uncertainty, the worthy aspiration to achieve a zero-tolerance policy on tsunami fatalities is set against the reduction in public alert compliance associated with previous false alerts. A risk-informed approach is presented, which outlines a decision process that allows for a decline in alert compliance due to false alerts. This risk-informed approach assesses probabilistically the tsunamigenicity of fault rupture, using data not just from historical catalogues but also the geological record. Prior probabilities could be automatically updated in real time by a Bayesian Belief Network from observations obtained in real time: earthquake depth information; pressure sensor recordings, tide gauge measurements; or visual reports of coastal inundation. A decision to issue a general evacuation warning in a specific region might be made provided the updated posterior probability reached a critical threshold.

Central America is a small and culturally homogeneous region that, since the 1990s, has experienced economic and political integration of its six countries, which share the same threats of volcanic eruptions, disastrous earthquakes and tsunamis. The Pacific coastline of 1700 km is common for Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica and Panama, and the Pacific subduction zone has the potential for creating huge tsunamis that threaten this coast. In addition to the natural hazard, the growing tourist industry is expanding its infrastructure along the Pacific beaches, which again enhances the exposure and tsunami risk. Even though the 1992 tsunami disaster in Nicaragua did not severely hit the tourist beaches, it raised the risk awareness, and special attention is now given to ‘slow’ earthquakes that may be modest in shaking while still having a large tsunami potential. The tsunami hazard mapping is well advanced in Nicaragua, Costa Rica and El Salvador, and initiatives are ongoing to improve the mapping in all countries. National systems for early warning were established in Nicaragua and El Salvador, while the other four countries rely on rapid information from the Pacific Tsunami Warning Center. Mitigation measures and information campaigns are presently conducted on a national basis in all countries, but a regional centre for early tsunami warning and coordinated information campaigns (CATAC) is expected to become operational in the near future.

Up until the late 1980s geology contributed very little to the study of tsunamis because most were generated by earthquakes which were mainly the domain of seismologists. In 1987–88 however, sediments deposited as tsunamis flooded land were discovered. Subsequently they began to be widely used to identify prehistorical tsunami events, providing a longer-term record than previously available from historical accounts. The sediments offered an opportunity to better define tsunami frequency that could underpin improved risk assessment. When over 2200 people died from a catastrophic tsunami in Papua New Guinea (PNG) in 1998, and a submarine landslide was controversially proven to be the mechanism, marine geologists provided the leadership that led to the identification of this previously unrecognized danger. The catastrophic tsunami in the Indian Ocean in 2004 confirmed the critical importance of sedimentological research in understanding tsunamis. In 2011, the Japan earthquake and tsunami further confirmed the importance of both sediments in tsunami hazard mitigation and the dangers from seabed sediment failures in tsunami generation. Here we recount the history of geological involvement in tsunami science and its importance in advancing understanding of the extent, magnitude and nature of the hazard from tsunamis.

The 2011 Tohoku earthquake, tsunami and resulting damage is often referred to as 3.11 after the date on which it took place. Leading to almost 20 000 people dead or missing, a major nuclear disaster and severe economic damage, 3.11 represents the biggest challenge faced by Japan since the end of World War II. Before 3.11, the possibility of a Mw 9 earthquake in this area was not generally recognized, highlighting the need to reassess seismic risk in NE Japan. The large amount of new quantitative data covering a range of disciplines and from onshore and offshore studies makes 3.11 an important case study that can contribute to improving our understanding of tsunamis, including their formation, their effects on coastal regions and the effectiveness of defensive measures old and new. Geological studies have a key role to play in this new phase of tsunami studies and this is the only method available for determining recurrence intervals over timescales of thousands of years. Data from 3.11 have improved our ability to identify sedimentary records of tsunami events and to estimate tsunami size from geological data. More complete databases will provide invaluable information for long-term planning of coastal regions in convergent plate margins.

The geology of any particular area imposes constraints on what humans can do. These constraints are generally thought of as geologic hazards, but access to the natural resources we all use and to recreational or scenic areas, may be local issues as well. The location of roads, bridges, reservoirs, landfills and other waste-disposal sites, etc., also have both geologic and public-policy consequences.As a society, we can either plan for or fail to plan for these consequences. If we allow people to build homes in floodplains, they will become flood victims. If we prohibit building on floodplains, we have impacted the value of those lands. Whose ox gets gored, how and when? Who pays? This trip won’t offer answers to these questions, it simply will point out that these are issues that ought to be debated and that we, as geologists, can contribute technical information relevant to the debates.The field trip will travel south along the central Front Range mountain front from Marshall to the US-285 roadcut at Turkey Creek with stops to look at burning coal seams, at the differences in mineral mining between Boulder and Jefferson Counties, to reflect on mountain flooding and the possibility that Leyden Gulch could capture Coal Creek, to look at the large rocks falling off the mountain and traveling through housing, at the Red Rocks Amphitheatre as a scenic area where geology is described for the public, and at the fossil oil reservoir and roll-front uranium deposit exposed in the Dakota sands.

The reuse of traditional construction materials attests to their high value over the long term. In fact, the practice has always demonstrated the inherent value of traditional raw materials and their products in confronting the issues of sustainability, in the broader sense of preserving resources – material and immaterial – for future generations. Throughout the history of building, the symbolic value of spolia (i.e. the use of ancient architectural elements in new construction) has gone hand-in-hand with the practice of recycling, demonstrating, at various levels, an intrinsic awareness of reuse as a tool for minimizing waste of materials and energy. Today, sustainability is rarely considered from a long-term perspective, and when it is, the approach tends to be from a broad theoretical standpoint. In the past, however, it was a common and necessary aspect of construction management, when the waste of materials was a forbidden luxury. This paper presents a review of the reuse of geomaterials, mainly stone, throughout the Italian history of construction, indicating major examples selected for their value as memorable references, describing common practices from antiquity to modern times, and concluding with a description of the actual state of the art of the practice, based on very recent and outstanding cases.

Local voluntary natural science societies played an important role in the development of early modern geotourism. This chapter explores the development of field, especially geological, excursions and their popularity in two local natural science societies – The Chester Society of Natural Science and the Woolhope Naturalists’ Field Club – from the 1850s to the 1950s. Both societies were established in the borderlands between England and Wales and had a strong emphasis on local and regional scientific studies. They exemplify broader trends in public engagement in the natural sciences and associated fieldwork consequent upon the British socio-political environment. Further, they draw out comparisons between the attitudes of society to excursions and scientific fieldwork, as well as involvement by social status and gender.

Using two hypothetical effusive events in the Chaîne des Puys (Auvergne, France), we tested two geographical information systems (GISs) set up to allow loss assessment during an effusive crisis. The first was a local system that drew on all immediately available data for population, land use, communications, utility and building type. The second was an experimental add-on to the Global Disaster Alert and Coordination System (GDACS) global warning system maintained by the Joint Research Centre (JRC) that draws information from open-access global data. After defining lava-flow model source terms (vent location, effusion rate, lava chemistry, temperature, crystallinity and vesicularity), we ran all available lava-flow emplacement models to produce a projection for the likelihood of impact for all pixels within the GIS. Next, inundation maps and damage reports for impacted zones were produced, with those produced by both the local system and by GDACS being in good agreement. The exercise identified several shortcomings of the systems, but also indicated that the generation of a GDACS-type global response system for effusive crises that uses rapid-response model projections for lava inundation driven by real-time satellite hotspot detection – and open-access datasets – is within the current capabilities of the community.

RED SEED stands for Risk Evaluation, Detection and Simulation during Effusive Eruption Disasters, and combines stakeholders from the remote sensing, modelling and response communities with experience in tracking volcanic effusive events. The group first met during a three day-long workshop held in Clermont Ferrand (France) between 28 and 30 May 2013. During each day, presentations were given reviewing the state of the art in terms of (a) volcano hot spot detection and parameterization, (b) operational satellite-based hot spot detection systems, (c) lava flow modelling and (d) response protocols during effusive crises. At the end of each presentation set, the four groups retreated to discuss and report on requirements for a truly integrated and operational response that satisfactorily combines remote sensors, modellers and responders during an effusive crisis. The results of collating the final reports, and follow-up discussions that have been on-going since the workshop, are given here. We can reduce our discussions to four main findings. (1) Hot spot detection tools are operational and capable of providing effusive eruption onset notice within 15 min. (2) Spectral radiance metrics can also be provided with high degrees of confidence. However, if we are to achieve a truly global system, more local receiving stations need to be installed with hot spot detection and data processing modules running on-site and in real time. (3) Models are operational, but need real-time input of reliable time-averaged discharge rate data and regular updates of digital elevation models if they are to be effective; the latter can be provided by the radar/photogrammetry community. (4) Information needs to be provided in an agreed and standard format following an ensemble approach and using models that have been validated and recognized as trustworthy by the responding authorities. All of this requires a sophisticated and centralized data collection, distribution and reporting hub that is based on a philosophy of joint ownership and mutual trust. While the next chapter carries out an exercise to explore the viability of the last point, the detailed recommendations behind these findings are detailed here.