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New directions in Seismic Hazard Assessment through Focused Earth Observation in the Marmara Supersite

WP6 : Earthquake Induced Landslide Hazard in Marmara

• P. Bigarré, INERIS

A major natural geohazard : seismic landsliding

M 6.7 Northridge, 1994, California Thrust, 19 km deep > 11.000 > 24 km2 Harp & Jibson, 1995 M 7.6 Chi-chi , 1999, Taiwan 100 km N-S fault segment > 20.000 > 150 km2 Lin et al, 2000 M 8 Wenchuan, 2008, Thrust, 20 km deep > 56 000 > 40 000 km2 Dai et al, 2011 M 7 Haiti, 2010 Thrust, 12 km deep, > 1 000 > 10 000 km2 USGS

The Sea of Marmara

The Sea of Marmara is prone to various geohazards, such as earthquakes, landslides, tsunamogenic submarine landslides (Gorur, 2009) :

• In Turkey total loss caused by landslides in terms of affected buildings

constitutes 27% of the entire loss from all natural hazards (Duman, 2005), especially in the seismically active NAF Zone (Gokceoglu, 2005)

• The 17 August 1999 Mw 7.4 Kocaeli earthquake caused extensive

landslides, subsidences and liquefaction-induced ground deformations along the coast of Izmit Bay (Cetin, 2004)

• Numerous tsunami occurrences are historically related to the earthquakes in

the segments of the WNAF (Altinok, 2000)

• Major submarine mass wasting - landslides have been observed and

mapped from high resolution surveys (Gazioglu , 2005)

• Tsunami effects were observed and measured during the 1999 post-event

surveys in several places along both the northern and the southern coasts of the Izmit bay (Tinti & al, 2006)

On shore : the Westward Metropolitan aera of Istanbul

Off shore : Entrance of the Gulf of Izmit

WP6 - Task1.a & 2.b: CNR ISMAR – ITU contributions (Luca Gasperini, Sinan

Ozeren) and CEREGE

Based on field geological observations, Duman et al. (2004, 2005a,b) have argued that the causes of the landslides are slope instability, shallow groundwater level, lithology and liquefaction.

WP6 - Task1.b: TUBITAK Contribution (Semih Ergintav)

Seismic lines shown on the map provide a link between the seismic sections and the structural features in this figure. Note the correlation between the locations of the heavy landslides and the fault zone (Ergintav, 2011). INTERACTIONS BETWEEN LANDSLIDES AND ACTIVE FAULTING

WP6 – Task2.b: IU - INERIS Contribution (Oguz Ozel, Stella Coccia)

The area shown in the map will be investigated in detail by microtremor measurements and other shallow geophysical measurements. The map is taken from TUBITAK Final Project Report,No: 5077101, 2008

Study Area

PREVIOUS STUDY

Investigation of site effects with new microtremor campaign

(Picozzi et al., 2009): Western part of Istanbul: single station noise measurements at free field sites (dots), IERRS stations (rhombus, name of stations with earthquake recordings is indicated), and 2D array measurements (squares). NEW STUDY

WP6 – Task2.b: IFSTTAR Contribution (Luca LENTI) & Third Party “La Sapienza”

from Lenti & Martino (2012)

Dynamic numerical models of interaction between seismic waves and landslides

Physical and mechanical parameters used for the FDM numerical modelling: den — density; ν — Poisson's ratio; G0 — elastic shear modulus; D0 — initial damping; Vs — shear wave velocity; ϕ — internal friction angle; c — cohesion; ten — tensile cut-off; dil — dilation angle; g — shear strain; G/G0 — shear modulus ratio; D/D0 — damping ratio. Validity of the attenuation law of Sabetta and Pugliese (1987),with related standard errors (dashed line), for the equivalent signals

• btained by LEMA_DES for each distance class.

Evaluation of permanent deformations on “first time” landslide slopes and/or pre-existing sliding processes by considering coupled scenarios

• f geological and hydrogeological conditions by the means of FD

nonlinear codes.

WP6 – Tasks 1.b and 2.b: IU - INERIS Contribution Seismic induced landslides susceptibility and mapping

Predictive Displacement Dn

Landslide susceptibility Hydrology Site effects Shaking

Seismic landsilde susceptibility

WP6 – Task2.b: IU - INERIS Contribution (Auxane Cherkaoui) Seismic induced landslides susceptibility and mapping A detailed procedure has been published by Westen (ICT). Kaynia et al (2011) have published on near to real time mapping of seismic landslides

Kinematics of Deep-seated Gravitational Slope Deformations from DInSAR time-series

Three-dimensional view and simplified geological cross-section for the Colle Cerese DGSD. Vertical scale is exaggerated ~2×. Legend: 1) Carbonate platform and ramp formations (Dogger [middle Jurassic]– lower Miocene); 2) Lacustrine deposits (Pleistocene); 3) Talus material, residual karst and fluvio-lacustrine deposits (Holocene); 4) Normal fault.

Descending LoS velocity map (values in mmyr−1). Legend: 1) Upper limit of DGSD; 2) Quaternary active fault; 3) Major trench; 4) Rock avalanche source area.

WP6 - Task1.b: INGV Contribution (Marco Moro)

WP6 – Task1.b: UNIPV Contribution (Paolo Gamba)

PMVE Spatial PMVE

WP6 – Partners and main tasks

3 5 6 8 9 13 17 18 Task / subtask TUBITAK INGV IU ITU CNR (ISMAR- IREA) INERIS UNIPV IFSTTAR Semih Ergintav Marco Moro Oguz Ozel Sinan Ozeren Luca Gasperini Pascal Bigarre Paolo Gamba Luca Lenti Task 1 Investigations of local instability areas - onshore and offshore – and developing of advanced susceptibility mapping Task 1a Off-shore landslide and Tsunami hazard In-depth survey

• f large

potential slides Task 1b On-shore landslides Interaction between landslides and structural geology Kinematics of Deep seated Gravitational slope deformations Advanced GIS Landslide hazard scale based on hyperspectral image data Task 2 Ground motion data, local seismic site effects and dynamic numerical modelling Task 2a Off-shore landslide and Tsunami hazard Numerical modeling of landslide generated tsunamis Task 2b On-shore landslides Sites effects – new micro- tremor campaign Advanced GIS Selection of landslide pilot site Dynamic Numerical modeling of permanent deformations

• f seismic

slopes