Too generous to a fault? Is reliable earthquake safety a lost art? Errors in expected human losses due to incorrect seismic hazard estimates

Abstract

"One is well advised, when traveling to a new territory, to take a good map and then to check the map with the actual territory during the journey." In just such a reality check, Global Seismic Hazard Assessment Program (GSHAP) maps (prepared using PSHA) portrayed a "low seismic hazard," which was then also assumed to be the "risk to which the populations were exposed." But time-after-time-after-time the actual earthquakes that occurred were not only "surprises" (many times larger than those implied on the maps), but they were often near the maximum potential size (Maximum Credible Earthquake or MCE) that geologically could occur. Given these "errors in expected human losses due to incorrect seismic hazard estimates" revealed globally in these past performances of the GSHAP maps (> 700,000 deaths 2001-2011), we need to ask not only: "Is reliable earthquake safety a lost art?" but also: "Who and what were the 'Raiders of the Lost Art?' "

Seismogenic nodes as a viable alternative to seismogenic zones and observed seismicity for the definition of seismic hazard at regional scale

“…As it has been much debated elsewhere (e.g. PAGEOPH Topical Volume 168, "Advanced Seismic Hazard Assessment" (2011) and references therein; Wyss et al, 2012;Bela, 2014), the use of historically tuned statistical indices for seismicity, based on the erroneous concept of "return period" and Poisson's statistical distributions, is rootless and unsafe, and, in particular, NDSHA does not use such assumptions. However, Eurocode 0 allows that for individual projects, which are one of the intrinsic abilities of NDSHA, design values may be otherwise specified.…”

NDSHA - The New Paradigm for RSHA - An Updated Review

“…In fact, there has always been clear evidence from the time it was authoratively first proposed that PSHA is wrong (Panza and Bela, 2019), but particularly within this past decade -with our benefit finally (calendarwise) now of true 2020 hindsight! (Wyss et al, 2012;Bela 2014;Mulargia et al, 2017;Stark and Freedman, 2016;Stark, 2017;Rugarli et al, 2019a) -we can say for certain that PSHA"s "technological inexactitudes", which unfortunately make up its body of knowledge, cannot ever reliably fulfill on either their presumptions or their promises! But, for a better future, this systemic problem remains: when parascience has a legal chrisom covering it, removing it can be very difficult!…”

“…PSHA, because it has too often delivered not only erroneous but also too deadly results (Wyss et al, 2012;and Bela, 2014), has remained a "conundrum," despite it having been extensively debated and also challenged over these last three decades. A comprehensive sample of contributions is contained in the PAGEOPH Topical Volume 168 (2011) and references therein.…”

Global Seismic Hazard Assessment Program - GSHAP legacy

“…Moreover, the occurrence of large destructive earthquakes (e.g. the M w 7.7, 2001, Gujarat, India, the M w 9.1, 2004, Sumatra-Andaman, Indonesia, the M w 7.9, 2008, Wenchuan, China, the M w 6.3, 2011, Christchurch, New Zealand, the M w 7.0, 2010, Port-au-Prince, Haiti and the M w 9.0, 2011, Tohoku, Japan earthquakes) in regions of relatively low seismic hazard, raised intense discussions on reliability of the GSHAP map, and in turn to the consistency of the use of probabilistic seismic hazard analysis (PSHA) to quantify of the earthquake-ground shaking hazard [Kerr 2011, Hanks et al 2012, Stein et al 2012, Wyss et al 2012, Frankel 2013, Iervolino 2013, Bela 2014, Stirling 2014, Wong 2014. Generally, the probabilistic approach implies the combination of the earthquake recurrence rates and ground motion empirical models (i.e.…”