The goal…

We provide a spatial-temporal distribution of large earthquakes (M 5.5+) occurred in Italy in the last 4 centuries

We provide a NONPARAMETRIC model of the Hazard Function no assumptions regarding the temporal

behaviour of the events

Physical/tectonic/geological parameters are taken into account to describe earthquake spatial distribution

1. Why an appropriate modelling? - it can provide important information about the

physics of earthquakes occurrence process

- it allows reliable earthquake forecasting.

2. So far, shared conclusions on statistical distributions could not be reached because of

Magnitude Threshold Spatial DomainVery often the distribution of large earthquakes is studied only in the temporaldomain selecting small seismic homogeneous areas with not enough datato verify the hypothses. For this reason quite different distributions (e.g. Poisson, Weibull, BPT, Gap, etc…) are commonly used in hazard studies.

The state of the art…

Parametric seismic catalog (CPTI) plus CSTI

M 5.5 Events since 1600 Spatial Grid:

Regular Grid

The data…

Proportional Hazard Model

)exp()(),( 0 βλλrrr

ztzt =

)(0 tλ

zr

βr

ASSUMPTION : earthquakes generation mechanism is the same for different areas; only the parameters can vary

Vector of Coefficients (Max Likelihood Estimation)

Vector of Covariates: it contains any spatial/tectonic information characterizing the Inter-Event Times (IETs) or the region where these are sampled

Base-Line Hazard Function, bearing information about the physics of the process

The method…

Results…

La variabile riportata nell’asse delle ordinate ha lo stesso andamento della Hazard Function.

Cluster Poisson

Results…

=10 anni

Results…

Evaluation of the “forecasting ability” of the model

(1950-2002)