000019874 001__ 19874
000019874 005__ 20170118182341.0
000019874 04107 $$aeng
000019874 046__ $$k2017-01-09
000019874 100__ $$aKohler, Monica
000019874 24500 $$aMapping Coherent, Time-Varying Wavefronts From the 2011 Tohoku Tsunami Into Enhanced, Time-Dependent Warning Messages

000019874 24630 $$n16.$$pProceedings of the 16th World Conference on Earthquake Engineering
000019874 260__ $$b
000019874 506__ $$arestricted
000019874 520__ $$2eng$$aRecent results are presented to illustrate how predictions of tsunami wave impact and tsunami warning messages can be improved by including information about multiple, large-amplitude wave arrivals over longer time durations and at refined spatial resolution. A deployment of ocean bottom seismometers off the coast of southern California recorded the March 2011 Tohoku tsunami on 22 differential pressure gauges. The pressure gauge tsunami records across the entire array show multiple large-amplitude, coherent phases arriving one hour to more than 36 hours after the initial tsunami phase. Analysis of the pressure gauge recordings reveals possible locations of the geographical sources that contributed to secondary tsunami arrivals in southern California. A beamforming technique is applied to the pressure gauge data to determine the azimuths and arrival times of scattered wave energy. In addition, a backward ray-tracing procedure is applied to a wide range of back azimuth starting values from the pressure gauge array to map possible scattering source locations. The results show several possible candidates of secondary tsunami source structures. These include: (1) southeastern Alaska producing a tsunami arrival 1–2 hours after the first arrival; and elongated bathymetry structures near: (2) the northern Hawaiian Island chain producing an arrival 1–2 hours, (3) Papua New Guinea producing an arrival 8–9 hours, and (4) French Polynesia producing an arrival 10–11 hours, all after the first arrival. These results are then incorporated into tsunami warning messages to improve clarity of the hazard threat and protective action guidance, and the specificity of impact location over time. Revised tsunami messages have been tested through online experiments with the public in order to determine how changes in message clarity and specificity affects message receiver understanding, believing, and personalizing, all of which are pre-decisional sense-making activities. The geophysical results are mapped into modified tsunami warning messages to show how a time-varying hazard could be communicated with more effective message format and content. The results are demonstrating the effects of including clearly described locations, time of impact, and hazard impact consequences on message perception among the public.

000019874 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000019874 653__ $$atsunami, beamforming technique, coherence stacking, back projection, tsunami warning

000019874 7112_ $$a16th World Conference on Earthquake Engineering$$cSantiago (CL)$$d2017-01-09 / 2017-01-13$$gWCEE16
000019874 720__ $$aKohler, Monica$$iSutton, Jeannette$$iAmpuero, Jean-Paul$$iShi, Jian
000019874 8560_ $$ffischerc@itam.cas.cz
000019874 8564_ $$s1310745$$uhttps://invenio.itam.cas.cz/record/19874/files/4587.pdf$$yOriginal version of the author's contribution as presented on USB, paper 4587.
000019874 962__ $$r16048
000019874 980__ $$aPAPER