Field measurements and numerical modeling for the run-up heights and inundation distances of the 2011 Tohoku-oki tsunami at Sendai Plain, Japan

Abstract

We conducted an urgent field survey at the Sendai Plain to measure the run-up heights and inundation distances of the 2011 Tohoku-oki tsunami. We used GPS measurements because of the remarkably long inundation distances (ca. 5.4 km). We established an accurate measurement scheme using the far electric reference points (about 350 km). Using this method, we quickly measured 69 run-up heights within 3 days. The tsunami run-up heights and inundation distances varied mainly according to the local topography, ranging from 9.6 m at 0.4 km to 0.2 m at 5.4 km, respectively. Furthermore, artificial structures and topography played an important role in constraining the inundation limit. Our observations are important for future analyses using aerial and satellite imagery and numerical modeling in the area because the maximum inundation area might be underestimated in the images as a result of the subtle traces of the tsunami inundation, which were difficult to identify in the field. However, results show that numerical modeling might not reproduce minor inundation beyond the highway without sufficiently high-resolution topographic data because data for the modeling are usually rough, and the highway, small channels, and street gutters, which played an important role in local inundation, are too small a resolution to be recognized in the model.

A simple parameterization for tsunami run-up prediction

“…While in this study the two combined effects of shoaling and refraction are considered, there are phenomena associated with wave behavior that play a role in run-ups are not yet incorporated, including effects of reflection and dispersion, and energy dissipation. Other external parameters, such as the geometry of the coast, coastal topography, and nearshore bathymetry may influence run-up parameterization, as claimed by some previous work on run-up and inundation estimation (Hayashi, 2010;Mori et al, 2011;Chen et al, 2012;Goto et al, 2013;Lin et al, 2014). For now, this study does not consider these effects as it concerns only on a simple parameterization for tsunami run-up prediction and therefore the incorporation of more local effects into the run-up estimate is challenging for future work.…”

“…(2). The calculated results are hereby compared to field data from observational studies available at http://www.ngdc.noaa.gov and direct surveys (Mori et al, 2011;Goto et al, 2013), and also to relevant data developed from numerical codes (Hirata et al, 2004;Lin et al, 2014). Detailed data and the calculated run-ups using Eq.…”

“…In turn, a decrease in the transport velocity must be compensated by an increase in the wave amplitude and hence the wave height inland, possibly causing severe damage on local structures and losses of human lives. This problem has therefore been an important issue in the context of disaster risk reduction as it gives rise to the importance of tsunami run-up prediction (Mori et al, 2011;Reymond et al, 2012;Goto et al, 2013).…”

“…The aim of this study is therefore to test and determine the applicability of the Green's law for tsunami run-up estimates using water depths as local parameters and orthogonal spacing widths of two adjacent refracted wave rays in the normal direction of wave fronts. In short, we include effect of wave refraction with no loss of energy in the basic Green's law for run-up prediction and then examine how close the results derived from the modified Green's law compared to run-ups obtained from simulations (Hirata et al, 2004;Lin et al, 2014) and field surveys (Goto et al, 2013).…”

Vulnerability assessment of archaeological sites to earthquake hazard: An indicator based method integrating spatial and temporal aspects

“…The susceptibility of a coastal area to geomorphological impacts from a tsunami mainly depend on coastal geomorphological and topographical factors that according to the literature have an effect on tsunami run-up, inundation depth and backwash dynamics that control the extent of the impacts [Dawson 1994, Matsutomi et al 2001, Choowong et al 2007, Goto et al 2011. Tsunami run-up and inundation dynamics vary significantly from site to site and studies have shown that the main controlling parameters are crustal deformation during the seismic event, orientation of propagation vector to the mean shoreline direction, distance from the tsunami generation area, bathymetry, coastal and land morphology [Geist 2001, Papathoma and Dominey-Howes 2003, Fritz et al 2011, Lekkas et al 2011.…”