On 27 February 2010, a magnitude M w = 8.8 earthquake occurred off the coast of Chile's Maule region causing substantial damage and loss of life. Ancestral tsunami knowledge from the 1960 event combined with education and evacuation exercises prompted most coastal residents to spontaneously evacuate after the earthquake. Many of the tsunami victims were tourists in coastal campgrounds. The international tsunami survey team (ITST) was deployed within days of the event and surveyed 800 km of coastline from Quintero to Mehuín and the Pacific Islands of Santa María, Mocha, Juan Fernández Archipelago, and Rapa Nui (Easter). The collected survey data include more than 400 tsunami flow depth, runup and coastal uplift measurements. The tsunami peaked with a localized runup of 29 m on a coastal bluff at Constitución. The observed runup distributions exhibit significant variations on local and regional scales. Observations from the 2010 and 1960 Chile tsunamis are compared.

In a laboratory wave tank, bores were generated by dam-break: by lifting a gate that initially separated quiescent shallow water from a volume of impounded water. The study was motivated by the problem of tsunami-structure interaction and sought to further the understanding of interactions between the bore-like flow of a broken tsunami wave and structures of different cross sections. Experiments were designed to observe the structure’s effect on the bore as well as the bore’s effect on the structure. This comprehensive study used highly repeatable experiments to measure water-surface variations, velocity flow fields, and forces exerted by bores on vertically erected columns. The temporal and spatial variations of the water-surface elevations were quantified with a Laser-Induced Fluorescence (LIF) technique; velocity flow fields were recorded with a combination of Laser Doppler Velocimeter (LDV) and Digital Particle Image Velocimetry (DPIV); forces on the columns were measured with a miniature load-cell transducer. The laboratory data obtained in the study are available for validating numerical models that predict forces on structures in unsteady flows.

Whereas the coast of Peru south of 10°S is historically accustomed to tsunamigenic earthquakes, the subduction zone north of 10°S has been relatively quiet. On 21 February 1996 at 21:51 GMT (07:51 local time) a large, tsunamigenic earthquake (Harvard estimate M w 7.5) struck at 9.6°S, 79.6°W, approximately 130 km off the northern coast of Peru, north of the intersection of the Mendaña fracture zone with the Peru-Chile trench. The likely mechanism inferred from seismic data is a low-angle thrust consistent with subduction of the Nazca Plate beneath the South American plate, with relatively slow rupture characteristics. Approximately one hour after the main shock, a damaging tsunami reached the Peruvian coast, resulting in twelve deaths. We report survey measurements, from 7.7°S to 11°S, on maximum runup (2-5 m, between 8 and 10°S), maximum inundation distances, which exceeded 500 m, and tsunami sediment deposition patterns. Observations and numerical simulations show that the hydrodynamic characteristics of this event resemble those of the 1992 Nicaragua tsunami. Differences in climate, vegetation and population make these two tsunamis seem more different than they were.This 1996 Chimbote event was the first large (M w \7) subduction-zone (interplate) earthquake between about 8 and 10°S, in Peru, since the 17th century, and bears resemblance to the 1960 (M w 7.6) event at 6.8°S. Together these two events are apparently the only large subduction-zone earthquakes in northern Peru since 1619 (est. latitude 8°S, est. M w 7.8); these two tsunamis also each produced more fatalities than any other tsunami in Peru since the 18th century. We concur with WIENS (1990, 1992) that this subduction zone, in northern Peru, resembles others where the subduction zone is only weakly coupled, and convergence is largely aseismic. Subduction-zone earthquakes, when they occur, are slow, commonly shallow, and originate far from shore (near the tip of the wedge). Thus they are weakly felt, and the ensuing tsunamis are unanticipated by local populations. Although perhaps a borderline case, the Chimbote tsunami clearly is another wake-up example of a ''tsunami earthquake.''

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This paper applies a simple energy method to predict characteristics of overland tsunami flows based on extrapolation of the energy grade line between the shoreline and the tsunami run-up limit. Starting with a mapped run-up or inundation limit from tsunami hazard maps or from field surveys, the method reconstructs maximum inundation depths and velocities across a flooded topographic transect to the shoreline. The energy method is evaluated first in comparison with thousands of numerical simulations conducted on idealized topographies using a freesurface wave model. The method is then evaluated in more detailed simulations over realistic topography using a second tsunami-evolution model. Finally, the method is evaluated against field observations of inundation depths from tsunami events in Chile and Japan. In all cases, inundation depths are predicted quite well, with little bias across a wide range of flow conditions and topographic conditions. Predicted velocities show less precision but seem to predict the general velocity decay from shoreline to run-up limit. The method then overestimates and provides a conservative estimate of the maximum momentum flux.

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