Project S3Project S3

Scenari di scuotimento in Scenari di scuotimento in aree di interesse aree di interesse prioritario e/o strategicoprioritario e/o strategico

CoordinatorsF. Pacor e M. Mucciarelli

GOALSGOALS

Compute Ground Motion scenarios in Italian areas in case of MAXIMUM CREDIBLE EARTHQUAKE occurrence

o The variability of the ground motion will be evaluated at different scales (inter or intra town).

o The expected strong motion will be estimated taking into account the variability of the input parameters used in the models.

Provide guidelines on

o The definition of ground motion scenarios

o The handling of different site conditions

Develope and apply new methods

o To evaluate seismic hazard at regional and local scale

Questions from RC(i) an overall synthesis of the status

of the project

(ii) the answer to the comments and questions of the RC,

(iii) the answer to the specific indications by the CR for improved inter-project coordination and integration,

(iv) the work plan for the last phase of the project,

(v) the plan for concrete implementation of the project results,

(vi) the adherence and the major changes of the project with respect to the planned activities for the past years

(vii) the prospects for successful implementation of the final project goals and in particular of the goals foreseen for the last phase

(viii) the explicit evaluation of the work and success of the various Rus,

(ix) a concise evaluation of the PIs of what could be the future evolution of the project field at the end of the present project.

An overall synthesis of PS3The first year of activity was devoted to data collection and set-up

of numerical models.

No problems were encountered during the field activities.

All the necessary numerical models were prepared and tested.

The project is now ready to move to its more challenging phase.

Some results are already achieved. The project attracted interest from researchers in Italy and abroad that volunteered for adding some unplanned researches at no extra cost (e.g., GFZ + Charles Univ. for 3d modelling of Tricarico Landslide and Gubbio Basin, Data Base of Vs30 profiles and amplification)

Main Questions from Reviewers 1. How to produce results suitable for the DCP loss estimate?

2. How to treat the uncertainties and their propagation through the damage evaluation process?

3. Why using only the Nakamura's technique to estimate site amplification?

4. What about soil non-linearity and liquefaction,

5. What about modelling the source dynamics?

Inter-project actionsRUs from S3 participated to the joint group on attenuation

together with RUs from other projects

A link was set up between PS3 and the DPC-ReLuis project.

A workshop was held with engineers, devoted to the interface problems

Data exchange with S5 regarding Task6 (Gubbio)

Data exchange with S2 for seismogenic sources

Plan for the last phase of PS3

No changes are foreseen for the activities of the second year of the project

Small addition of field work are foreseen if the budget will permit them

Implementation of PS3 results

For the test areas of Potenza and Gubbio, an agreement was reached with the local administrators to assist them in fully exploiting the project results

A technical meeting with DPC is due in a short time, to fix the technical issues of GIS compatibility

For the Vs30 topic, a public meeting will be held inviting representatives of practitioners (geologists and engineers)

All the deliverable will be accessible through the PS3 web page

Adherence and/or major changes

No changes are foreseen for the second year.

All the expected deliverable due up to now were ready on schedule.

Two deliverables were prepared in addition to the list of the expected ones (D0 - D26)

Evaluation of RU works

All the RUs completed the assigned tasks on time

No problems were encountered in data flow and information excange

Some RU performed some additional work not requested at the beginning, following needs that arose during the first year

Evolution of the PS3 project

TASK 1: Simulation techniques

Activity 1 - Comparison between simulation techniquesThe aim is to evaluate the capability of each simulation technique to reproduce the main features of the strong motion data in differentfrequency bands.

Activity 2 - Parametric studiesThe aim is to perform a sensitivity analysis to test the ground motion variability for different source parameters.

Activity 3 - Development of new approachesDevelopment of new approaches

Modelling the 1980 Irpinia earthquake M 6.9Deliverable D0

Deterministic method

Okada: Static displacements using a dislocation model in an elastic, homogeneous, isotropic half-space

Compsyn: the finite element and finite difference numerical methods is used to calculate synthetic ground motion seismograms

Hybrid method

HIC:combines 1) the integral approach at low frequencies, based on the representation theorem and the k-squared slip distribution composed by the subsources, and 2) the composite approach at high frequencies, based on the summation of ground motion contributions from the subsources.

DSM:Combines 1) isocron theory to compute acceleration envelope 2) the point source stochastic method with reference spectrum defined by the apparent corner frequency and fault distance

Comparison

betweensyntheticscomputed with4 methods

Compsyn - 2.5Hz

HIC - 10 Hz

DSM 0.5 – 25 Hz

Comparison with data

Bagnoli station

0sec event: PGA maps

from NW to SE Bilateral

from SE to NW

DSM

from NW to SE Bilateral

from SE to NW

HIC

TASK 2: Site effects

It is very important to take into account site effects to produce realistic ground motion scenarios.The aim is to verify if and when it is possible to provide simplified but reliable estimates of site response.Two research lines are planned

Vs30Validation of the predictive capability of S waves average velocity in the first 30 meters to estimate the seismic site response

Particular site conditionsParticular site conditionsEvaluation of the site-dependent seismic response for typical geo-morphological condition, with insufficient seismic characterization

Tito Scalo Test Site

Geophysical investigation

Left: NASWRight: Down-Hole.

0

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0.1 1 10freq (Hz)

H/V

H/V triggered noise (average of 674 data)H/V earthquakes (average of 132 events)H/V ambient noise data1Dmodel NASW1Dmodel Down-HoleSSR1D model geotecnica

Comparison between transfer function

NASW and Down-Hole

Fractured rock masses

Spectral amplification as a function of frequency and direction

Tremestieri Fault

Velocity Inversion(a) (b)

(c)

(a) (b)

(c)

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0.0 0.1 0.2 0.3gmax(%)

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0 100 200 300 400t max (kPa)

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0 0.1 0.2 0.3

amax (g)

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ta (m

) 

EERAQUAD4MDESRAFLACLineare

Landslides

CAR3

Diagrammi a rosa dell’intensità di Arias calcolata su componenti orizzontali ruotate ad intervalli azimutali di 10° per diversi eventi registrati nell’area di studio nelle stazioni CAR1, CAR2, CAR3 e nella stazione su roccia ORC (Ortucchio) della RAN.

TASK3: Molise Area - Bedrock scenarios

1. Definition of the seismogenic sources for the two main shocks, definition of 1D propagation medium at local and regional scale.

2. Collection of the recorded data during the Molise seismic sequence (about 150 events with M> 2.5). Merging of velocimetric and accelerometric data to estimate seismological parameters.

3. Estimation of a spectral model to provide attenuation parameters, source function and empirical transfer function. Attenuation relationships of PGA, PGV and PSV will be also estimated (Scenarios level 0).

4. Modelling of the two main shocks with simple (scenarios level 1) and complex simulation technique (scenarios level 2) and calibration of model parameters through comparison with recorded data

5. Computing bedrock seismic scenarios at S. Giuliano di Puglia; Bonefro; Ripabottoni, Colletorto e Santa Croce di Magliano

Attenuation lawComparison withUmbria Marche attenuationσ++++= 2,11010 loglog sRcbMaY

We calibrated the model for PGA and PGV.

The models are derived for both the maximum horizontal and vertical (V) components.

The coefficients a, b, c, d and s1,2 are determined by applying the random effects model

The inter-event, inter-station, and record-to-record components of variance are estimated

Simulation of the mainshock

1. Deep geo-electric tomography 2,5D at S. Giuliano di Puglia to reconstruct the subsoil.

2. 3-D Model of S. Giuliano di Puglia

3. Collection and interpretation of geotechnical and geological data to define the mono, bi and tri-dimensional models (where possible). They will be used to evaluate the response site in the five towns.

4. Soil-building interaction study at Bonefro

5. Transfer function and/or amplification factor to be used in the generation of shaking scenarios at the sites

6. Computing site shaking scenarios and comparison with damages

7. Set-up of a G.I.S with input data, intermediate and final results for the five cities.

Site ground motions scenarios

Geo-electricalTomography

City-soil interaction (Bonefro)

1500 m/s

Vs (m/s)

Syntetic seismograms with and without buildings

Amplitde spectraSpectral Ratio

( / )Accelerograms

clay bedrock

f (Hz) f (Hz)f (Hz) f (Hz)

0 2 4 6−2

−1

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1

2

3x 10

−6

x ac

c

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8x 10

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0 2 4 6−4

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TASK4: Garda Area Bedrock scenarios

1. Definition of the seismogenic source of the main shock, definition of 1D propagation medium at local and regional scale.

2. Collection of the recorded data during the Garda seismic sequence (about 100 earthquakes ). Data analysis to estimate attenuation parameters

3. Computation of empirical attenuation relationships for peak ground motion (Scenarios level 0).

4. Modelling of the main shocks with simple (scenarios level 1) andcomplex simulation techniques (scenarios level 2) and calibration of model parameters through comparison with recorded data

5. Computing bedrock seismic scenarios at Vobarno, Salò, Gardone Riviera, Toscolano-Maderno.

Intensity scenarios

Isotropic Model

Shaking scenarios – level 1

A

D

Validation

[ ] 57.6/log83.1 2max +⋅= smaI [ ] 52.8/log65.1 max +⋅= smvI

Faccioli, E., Cauzzi, C. (2005)

Site shaking scenarios1. Collection of the microzonation and vulnerability data performed by the

Region before the Salò earthquake.

2. Noise measurements campaign at the Vobarno, Salò, Gardone Riviera, Toscolano-Maderno cities

3. Noise measurements campaign inside buildings of some selected cities

4. Comparison between microzonation studies and result obtained by the Nakamura technique; comparison between vulnerability data and noise results by measurements performed inside the buildings

5. Transfer function and/or amplification factor to adopt in the generation of shaking scenarios at the sites

6. Computing of site shaking scenarios and comparison with damages

7. Set-up of a G.I.S with input data, intermediate and final results for the five cities.

GIS Interface

The measurementsites wereidentified usingGIS system. Damageinformationwere combinedwith territorialand geologicaldata.

TASK5 – Potenza - Bedrock shaking scenarios

1. Characterization of the seismogenic sources to define the MCE, definition of 1D propagation medium at local and regional scale

2. Collection of the recorded data recorded in Southern Italy and analysis data to estimate seismological parameters.

3. Estimation of spectral model to provide attenuation parameters, source function and empirical transfer function. Attenuation relationships of PGA, PGV and PSV will be also estimated (Scenarios level 0).

4. Modelling of the main seismic sources with simple (scenarios level 1) and complex simulation techniques (scenarios level 2) and calibration of model parameters through comparison with recorded data

5. Computing bedrock seismic scenarios at Potenza.

Task 5 – Potenza Site shaking scenarios

1. Reappraisal and refining of microzonation studies in Potenza.

2. Collection of vulnerability data.

3. Noise measurements campaign inside selected buildings.

4. Transfer function and/or amplification factor to adopt in the generation of shaking scenarios at the sites

5. Computing of site shaking scenarios

6. Set-up of a G.I.S. with input data, intermediate and final results for Potenza city.

Irpinia Fault

Aul Bag Bis Bri Cal Mer Rio Stu Pot100

101

102

103

PG

A [c

m/s

2]

Station

Simulated PGA rangesRecordedSabetta&Pugliese 96

Soil resonance frequency

Frequency and dampingof buildings

Task 6 - Gubbio

Task 7 – Interfacciamento con l'ingegneria ed il DPC