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Tsunamis are unpredictable and infrequent but potentially large impact natural disasters. To prepare, mitigate and prevent losses from tsunamis, probabilistic hazard and risk analysis methods have been developed and have proved useful. However, large gaps and uncertainties still exist and many steps in the assessment methods lack information, theoretical foundation, or commonly accepted methods. Moreover, applied methods have very different levels of maturity, from already advanced probabilistic tsunami hazard analysis for earthquake sources, to less mature probabilistic risk analysis. In this review we give an overview of the current state of probabilistic tsunami hazard and risk analysis. Identifying research gaps, we offer suggestions for future research directions. An extensive literature list allows for branching into diverse aspects of this scientific approach. © Copyright © 2021 Behrens, Løvholt, Jalayer, Lorito, Salgado-Gálvez, Sørensen, Abadie, Aguirre-Ayerbe, Aniel-Quiroga, Babeyko, Baiguera, Basili, Belliazzi, Grezio, Johnson, Murphy, Paris, Rafliana, De Risi, Rossetto, Selva, Taroni, Del Zoppo, Armigliato, Bureš, Cech, Cecioni, Christodoulides, Davies, Dias, Bayraktar, González, Gritsevich, Guillas, Harbitz, Kânoǧlu, Macías, Papadopoulos, Polet, Romano, Salamon, Scala, Stepinac, Tappin, Thio, Tonini, Triantafyllou, Ulrich, Varini, Volpe and Vyhmeister.

In our efforts to calibrate regional crustal paths and upper-mantle teleseismic effects for the Middle East and North Africa we have extended the coverage to include the Western Mediterranean and North Africa, a region of sharp lateral variations in the crustal waveguide. Such calibration is for use in regional magnitude corrections and path attenuation relations. We have established a regionalized zonation of surface wave paths at longer periods (T> 15 secs) and presently have a first-order working model for Pnl propagation across old oceanic paths. In the area previously calibrated -- centered about the Pamir-Hindu Kush region, and covered by the IMS b-stations NIL and AAK, we have analyzed the performance of our source location and characterization methods to smaller (4 > ML> 3) earthquakes using data from co-located or nearby temporary arrays. We establish from this analysis that two broadband three-component stations can provide useful location and depth estimates for small regional events with few (1 or 2), if any, teleseismic observations. A serendipitous result of this work is a depth estimator based on a signal's S-wave complexity. This technique is also complimentary to the short- period:long-period (Esp-pz:Eip-3) discriminant., Original contains color plates: All DTIC/NTIS reproductions will be in black and white.

We have analyzed observations of earthquakes occurring in the Hindu-Kush region to establish a basis for location and discrimination using the new broadband station NIL, a GSETT-3 beta station, which is located near the site of the GSETT-3 alpha array PKAR in Pakistan. Preliminary analyses of the regional data at NIL in terms of energy ratios (the integrated energy in the short-period Pn1 wavetrain, divided by the intermediate-period, three component, surface wave integrated energy) produces plots not unlike those produced by a similar analysis of TERRAscope data (for the southwestern U.S.). NTS explosions consistently plot higher than regional earthquakes in the latter population, Woods and Helmberger (1996). In the NIL earthquake population, there are observed events with high ratios which look like explosions but appear to be deep events where the surface waves have become weak relative to the body waves. The identical problem occurs for the mb:Ms discriminants for events in this region. Thus, the ability to determine the source depth becomes crucial in this region as a complimentary method to infer the source type. To calibrate the regional paths we selected 5 crustal and 5 sub-crustal events (5.5