The new Italian seismic hazard model (MPS19)

Abstract

We describe the main structure and outcomes of the new probabilistic seismic hazard model for Italy, MPS19 [Modello di Pericolosità Sismica, 2019]. Besides to outline the probabilistic framework adopted, the multitude of new data that have been made available after the preparation of the previous MPS04, and the set of earthquake rate and ground motion models used, we give particular emphasis to the main novelties of the modeling and the MPS19 outcomes. Specifically, we (i) introduce a novel approach to estimate and to visualize the epistemic uncertainty over the whole country; (ii) assign weights to each model components (earthquake rate and ground motion models) according to a quantitative testing phase and structured experts’ elicitation sessions; (iii) test (retrospectively) the MPS19 outcomes with the horizontal peak ground acceleration observed in the last decades, and the macroseismic intensities of the last centuries; (iv) introduce a pioneering approach to build MPS19_cluster, which accounts for the effect of earthquakes that have been removed by declustering. Finally, to make the interpretation of MPS19 outcomes easier for a wide range of possible stakeholders, we represent the final result also in terms of probability to exceed 0.15 g in 50 years.

Earthquake Rupture Forecasts for the MPS19 Seismic Hazard Model of Italy

“…Nodal planes are used to define the three-dimensional position of the ruptures while rake is utilized to attribute the correct coefficients of the GMMs. Meletti et al [2021] compiled a collection of new datasets to be used as inputs for ERF development in MPS19.…”

“…We based the assessment of Mmax on the estimate of the maximum observed earthquake in the historical seismicity record from CPTI15. First, we divided the study area into different tectonics domains (#1-#19 in Figure 1d), based on (i) seismotectonic data by Meletti et al, [2021], (ii) a regionalization proposed by Delavaud et al [2012], for GMMs applicability and, (iii) the superzones (as in the European seismic hazard model, ESHM2013) for the evaluation of the maximum magnitude [Woessner et al, 2015]. Secondly, we assigned the earthquakes in CPTI15 to the respective tectonic domains where they are located.…”

“…In 2015, the Seismic Hazard Center (Centro di Pericolosità Sismica, CPS) of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) was commissioned by the Italian Civil Protection Department to engage and coordinate the national scientific community to elaborate a new seismic hazard model for Italy [Modello di Pericolosita� Sismica, MPS19 hereafter, details in Meletti et al, 2021]. The definition of MPS19 has engaged about one hundred workers from research institutes and universities through an open call to the Italian scientific community [Appendix A in Meletti et al, 2021]. The MPS19 project was organized into six tasks, each one of them led by two coordinators.…”

“…The primary requirement of the Italian Civil Protection Department was the production of a timeindependent PSH model [Meletti et al, 2021]; in this framework, the ERFs were developed with the purpose of (a) being coherent and applicable within the MPS19 project, (b) distinguishing between aleatory variability and epistemic uncertainty, and (c) verifying their reliability. This paper is not aimed at describing in detail each single ERF input, which deserves specific papers and reports; here, we briefly present the key differences among them to provide a sufficient degree of knowledge of the characteristics of the inputs.…”

Probabilistic Tsunami Hazard and Risk Analysis: A Review of Research Gaps

“…While validation of individual components has been addressed in several of the sections in our text, validating the PTHA and PTRA workflow as a whole is still ongoing research. Marzocchi and Jordan (2014) propose a methodology for a meaningful test of general probabilistic hazard models and an example of a successful application can be found in Meletti et al (2021).…”