SISMA: Workshop finale ASI, 4 maggio 2011

Il Progetto Progetto SISMA:

razionale, attività e principali risultati

Roberto Sabadini

Università degli Studi di Milano

SISMA: Workshop finale ASI, 4 maggio 2011

SISMA new approach towards the understanding of SISMA new approach towards the understanding of earthquake generation and seismic hazard mitigation builds earthquake generation and seismic hazard mitigation builds

over three major concepts:over three major concepts:

taking advantage of the new generation of DINSAR and GPS deformation data at the Earth’s surface in conjunction with seismic flow monitoring

which in turn allows us

building an integrated geophysical, geodetic and seismological scheme to disclose stress build up within the gouge of sesmic active faults for a deterministic approach of earthquake cycle description

which in turn allows us

overcoming the obvious shortcomings of the old approach to seismic hazard mitigation based on a purely probabilistic approach

SISMA: Workshop finale ASI, 4 maggio 2011

Restrained areasFor SAR and GPS

Establishment of a localnetwork of GPS Receiver

set uo on monumented sites,co-located with proper CAT

GeophysicalForward Modellingof stress build up in the fault gouge

PermanentGPS

Formalized analysisof seismicity update

Evaluation of seismic hazard

GPS data processing to retrieve

continuously updated deformation and

velocity maps

Acquisition of the historicalSAR images of the area andrequest to running Missions

(e.g. Cosmo Skymed) to planning new observations.

SAR data processing to retrieve

continuously updated deformation and

velocity maps

SISMA: Workshop finale ASI, 4 maggio 2011

SISMA: Workshop finale ASI, 4 maggio 2011

SISMA: Workshop finale ASI, 4 maggio 2011

SISMA: Workshop finale ASI, 4 maggio 2011

SISMA: Workshop finale ASI, 4 maggio 2011

stima deformazione: TIN vs Poligoni (da ZS9)

SISMA: Workshop finale ASI, 4 maggio 2011

SISMA: Workshop finale ASI, 4 maggio 2011

SISMA: Workshop finale ASI, 4 maggio 2011

SISMA: Workshop finale ASI, 4 maggio 2011

SISMA: Workshop finale ASI, 4 maggio 2011

Northern Region, M o=5.4

6 .5 5 .4 5 .8 6 .0

1965 1975 1985 1995 2005

5 .5 5 .6 5 .5

Central Region, M o=5.65 .86 .0 6 .5

5 .76 .0

1955 1965 1975 1985 1995 2005

5 .7

Southern Region, M o=5.65 .86 .0 6 .55 .8

1955 1965 1975 1985 1995 2005

5 .76.5 5 .4 5 .8 6 .0

1965 1975 1985 1995 2005 2015

5.55 .65 .5

5 .86 .0 6.5

5 .76 .0

1955 1965 1975 1985 1995 2005 2015

5 .7 6.35 .86 .0 6 .55 .8

1955 1965 1975 1985 1995 2005 2015

5.7

M5.5+M5.5+ M6.0+M6.0+ M6.5+M6.5+

CNCNalgorithmalgorithmTimes of Increased Probability for the occurrence of events with M>Mo within the monitored regions

Monitored region

Alerted region

M8S M8S algorithmalgorithm

SISMA: Workshop finale ASI, 4 maggio 2011

Geodetic and seismic integration: IBAY map

Red = geodetic anomalies plus seismic alertGreen = neither geodetic anomalies

nor seismic alertYellow = geodetic anomaliesOrange = seismic alert

The numbers in the red zones give the relative alert value.

SISMA: Workshop finale ASI, 4 maggio 2011

Local ground shaking Local ground shaking scenario for the Gubbio scenario for the Gubbio

sitesite

Ground motion Ground motion scenarios scenarios

at local scaleat local scale

Detailed scenarioDetailed scenarioss of of ground motionground motion, , including including site effectssite effects ((2D sections 2D sections

describing the mechanical describing the mechanical properties properties

of the sites)of the sites), are defined , are defined at the local scale at the local scale

for for the the alerted faults.alerted faults.

Synthetic seismograms

Spectral amplifications

2D laterally heterogeneous

local profile

SISMA: Workshop finale ASI, 4 maggio 2011

Conclusions Although the seismic classification of the Italian territory has been

recently revised, the evaluation of seismic hazard continue to be based on the traditional probabilistic approach, i.e. on the probabilistic analysis of earthquake catalogue and of ground motion information, retrieved by macroseismic observations and instrumental recordings, that may lead to severe underestimations of seismic hazard.

Recently this approach showed its limitation in providing a reliable seismic hazard assessment, possibly due to the insufficient information about historical seismicity, which can introduce relevant errors in the purely statistical approach mainly based on the seismic history.