A classification of mitigation strategies for natural hazards: implications for the understanding of interactions between mitigation strategies

Abstract

The unexpectedly poor performances of complex mitigation systems in recent natural disasters demonstrate the need to reexamine mitigation system functionality, especially those combining multiple mitigation strategies. A systematic classification of mitigation strategies is presented as a basis for understanding how different types of strategy within an overall mitigation system can interfere destructively, to reduce the effectiveness of the system as a whole. We divide mitigation strategies into three classes according to the timing of the actions that they prescribe. Permanent mitigation strategies prescribe actions such as construction of tsunami barriers or landuse restrictions: they are frequently both costly and ''brittle'' in that the actions work up to a design limit of hazard intensity or magnitude and then fail. Responsive mitigation strategies prescribe actions after a hazard source event has occurred, such as evacuations, that rely on capacities to detect and quantify hazard events and to transmit warnings fast enough to enable at risk populations to decide and act effectively. Anticipatory mitigation strategies prescribe use of the interpretation of precursors to hazard source events as a basis for precautionary actions, but challenges arise from uncertainties in hazard behaviour. The NE Japan tsunami mitigation system and its performance in the 2011 Tohoku disaster provide examples of interactions between mitigation strategies. We propose that the classification presented here would enable consideration of how the addition of a new strategy to a mitigation system would affect the performance of existing strategies within that system, and furthermore aid the design of integrated mitigation systems.

Assessment of Educational Methods for Improving Children’s Awareness of Tsunamis and Other Natural Disasters: Focusing on Changes in Awareness and Regional Characteristics in Japan

“…These authors show that awareness of tsunamis on the Sanriku coast was higher because it had been impacted by recent tsunami (in 1896 and 1933) whereas the Sendai coast had not, and infer that this elevated awareness led in most places to more effective evacuation behaviors. A similar conclusion was reached in earlier investigations within the Sanriku region by Ando et al (2013) [8], and in the analysis by Day and Fearnley (2015) [9], who emphasized that prior learning about hazards and evacuation behaviors is essential for effective human evacuation behavior in response to warnings from even the most advanced alarm and defense systems.…”

“…Comparative studies of different regions affected by the 2011 tsunami disaster by [6] and Latcharote et al (2017) [7] show that fatality ratios for given tsunami intensities in the 2011 tsunami disaster were lower on the Sanriku Ria coast than on the Sendai coast. These authors show that awareness of tsunamis on the Sanriku coast was higher because it had been impacted by recent tsunami (in 1896 and 1933) whereas the Sendai coast had not, and infer that this elevated awareness led in most places to more effective evacuation behaviors.…”

Volcano Crisis Communication: Challenges and Solutions in the 21st Century

“…Monitoring information is often combined with pre-determined patterns or thresholds and with conceptual models pertaining to the dynamics of magmatic systems to forecast outcomes of volcanic unrest. Current practitioners of Bayesian Event Tree (BET) analysis use either the Cooke-Aspinall method (Cooke 1991;Aspinall 2006) or the INGV (National Institute of Geophysics and Volcanology) method (Marzocchi et al 2004(Marzocchi et al , 2008, although there are other implementations (e.g., Sobradelo et al 2014;Jolly et al 2014;Newhall and Pallister 2015). In addition, Bayesian Belief Networks (BBN), another graphic method that does not require the same type of linear time progression as in BET systems, may be used effectively in some situations (e.g., Lindsay et al 2010;Hincks et al 2014;Aspinall and Woo 2014).…”

Civil protection and Damaging Hydrogeological Events: comparative analysis of the 2000 and 2015 events in Calabria (southern Italy)

“…Moreover, they can play an important theoretical guiding role in meteorological disaster prediction, and future disaster prevention and reduction (Guan et al, 2015). In fact, an insight into past disasters allows assessing the performances of multiple mitigation strategies (Day and Fearnley, 2015) and, consequently, to help in the management of future events in which the simultaneous occurrence of landslides and floods must be taken into account. Especially for floods frequency estimation, the value of historical data is generally recognised in different countries, but practical methods for systematic and routinely inclusion of these data into risk analysis are rarely available, even though harvesting data on past extreme events could improve the reliability of flood risk assessments (Kjeldsen et al, 2014).…”