[ghsc-seminars] Reminder: TOMORROW, Friday @ 2 pm, GHSC Seminar: Carlos Meletti, Istituto Nazionale di Geofisica e Vulcanologia, =?UTF-8?B?TOKAmUFxdWlsYQ==?=, Italy

[Oliver Boyd]

THE NEW ITALIAN NATIONAL SEISMIC HAZARD MODEL 

Carlo MELETTI1

In collaboration with: 

Warner MARZOCCHI1,

Bruno PACE2

Francesco VISINI1

MPS16 Working Group

 

1Istituto Nazionale di Geofisica e Vulcanologia, L’Aquila, Italy

2Università degli Studi di Chieti-Pescara Disputer Department, Chieti, Italy

 

In 2015 the Seismic Hazard Centre (Centro Pericolosità Sismica – CPS) of the National Institute of Geophysics and Volcanology (INGV) was commissioned to engage and coordinate the national scientific community with the aim of elaborating a new reference seismic hazard model, mainly designed to update the seismic code. The Civil Protection Department (DPC) funded the project; the main requirements for the model were defined throughout meetings with national experts in earthquake engineering that will then participate to the revision of the building code. The CPS outlined a roadmap to release within three years a significantly renewed PSHA model, with regard to both the updated input elements and the strategies to be followed. 

Since the beginning, CPS fixed some key constraints that had to be honoured when building a seismic hazard model for practical purposes. These points, which basically aim to guarantee a large participation and the scientific and non-scientific consensus, can be summarized as follows: (i) the use of international standards according to the state of the art in Probabilistic Seismic Hazard Assessment (PSHA) (e.g. SHAAC, 1993); (ii) open and transparent procedures that guarantee totally reproducible outcomes; (iii) the use of outputs to be approved by the stakeholders; (iv) the involvement of Italian scientific community as large as possible in proposing data, models and approaches; (v) a full and coherent exploration and representation of the epistemic uncertainty in the final seismic hazard model; (vi) the implementation of a robust testing phase, and of an elicitation session with national and international independent experts, in order to check the reliability of each component of the seismic hazard model.

Following a public call, about 150 people from universities and research institutions have been involved in the project.

The activities were organized in 6 tasks: T1) project management, T2) input data, T3) seismicity models, T4) ground motion and intensity predictive equations (GMPEs and IPEs), T5) computation and rendering, T6) testing.

T1 planned the activities and managed the other 5 tasks to ensure achievements of the Project scopes. 

T2 selected the most updated information about historical and instrumental seismicity, seismogenic faults, and deformation (both from seismicity and geodetic data) and compiled the necessary databases. The task released 15 deliverables, shared with all the participants.

T3 elaborated the seismicity models in terms of classic source areas, fault sources and gridded seismicity based on different approaches, with associated seismicity rates. Each earthquake rate model has to be reproducible, according a full description of its “making of”. Moreover, modellers have to explore the epistemic uncertainty related to their model; this step is crucial to estimate an overall epistemic uncertainty of the final model, which includes the uncertainty of each model and the uncertainty among models.

T4 selected the most recent models accounting for their tectonic suitability and forecasting performance. The forecasting performance of each GMPE has been evaluated through the comparison with accelerometric records available in the Italian (itaca.mi.ingv.it) and European (esm.mi.ingv.it) strong-motion databases. In this way, each GMPE has been ranked according to different specific metrics, so that the best performing GMPEs can be identified.

T5 identified the code OpenQuake (www.openquake.org) for calculation. It is open source and we had a large interaction with the IT team in order to modify or integrate the code, as well as to ask for the development of new, dedicated functions.

T6 performed statistical procedures to test, with the available data, the whole seismic hazard models, and single components such as the seismicity models and the GMPEs. T6 also organised the elicitation session and finally weight the different models.

The MPS16 model was implemented also according the suggestions of a revision panel (5 Italian experts selected by DPC) that was informed every 2 months about the activities of CPS. The release of the final model is scheduled for December 2018.

Friday, June 22nd, 2018, 2 pm (Mountain Time)
USGS, 1711 Illinois Street, Golden, CO
Entry Level Seminar Room (204)

*Note: Please arrive ~5 minutes early and bring photo ID for airport-style security measures now in place at the USGS building.

Thank you,
GHSC Seminar Committee 

Mirus, Ben - bbmirus at usgs.gov
Josh Rigler - erigler at usgs.gov
Oliver Boyd - olboyd at usgs.gov

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