Changes in Tsunami Risk to Residential Buildings at Omaha Beach, New Zealand

Abstract

Coastal settlements worldwide have suffered significant damage and loss to tsunami hazards in the last few decades. This period coincides with socio-economic changes that have heightened spatio-temporal risk through increased coastal development and infrastructure. In this study, we apply a spatio-temporal loss model to quantify the changes in direct economic losses to residential buildings from tsunami hazards over a 20-year period in Omaha Beach, New Zealand. The approach reconstructed temporal urban settlement patterns (1992, 1996, 2006 and 2012) for an area potentially exposed to regional source tsunami inundation hazard. Synthetic depth–damage functions for specific building classes were applied to estimate temporal damage and loss from tsunami inundation exposure at each building location. Temporal loss estimates were reported for a range of risk metrics, including probable maximum loss, loss exceedance and average annual loss. The results showed that an increase in the number of buildings and changes to building design (i.e., storeys, floor area, foundations) influenced the increasing risk to direct economic loss over the study period. These increases were driven by conversion from rural to urban land use since 1996. The spatio-temporal method presented in this study can be adapted to analyse changing risk patterns and trends for coastal settlements to inform future tsunami mitigation measures and manage direct economic losses.

Multiscale Quantification of Tsunami Hazard Exposure in a Pacific Small Island Developing State: The Case of Samoa

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Quantifying National-Scale Changes in Agricultural Land Exposure to Fluvial Flooding

“…Exposure mapping was undertaken by using the RiskScape multi-hazard risk model framework [53]. This modular framework is configured to produce exposure and impact data by analyzing hazard data and the characteristics of the assets at risk, and it has been applied in exposure studies in New Zealand and the wider Pacific region [54][55][56][57][58]. The RiskScape engine computes user-defined risk/exposure/vulnerability calculations for these hazards and assets.…”

The paleotsunami record of the Auckland region and implications for understanding tsunami hazards

“…Previous research has identified several coastal sites within the Auckland region that have evidence of past marine inundation attributed to tsunamis (Figure 1; Nichol et al 2003Nichol et al , 2007De Lange and Moon 2007) and Goff et al (2005) collated evidence for five paleotsunamis affecting the Auckland region in the past ∼2600 years. While a number of probabilistic tsunami hazard and risk studies for the Auckland region have been undertaken recently (Lane et al 2013;Power et al 2013Power et al , 2017Paulick et al 2019), the paleotsunami question has not been revisited since the 2005 report by Goff et al…”