1. Use of Paleoseismic Data in Seismic Hazard Analysis: Examples from Europe K.Atakan and A.Ojeda Institute of Solid Earth Physics University of Bergen Allégt.41, N-5007 Bergen, Norway Tel: +47-55-583413 Fax: +47-55-589669 E-post: atakan@ifjf.uib.no

2. Probabilistic Seismic Hazard Assessment Seismic Risk Class Historical seismicity Active fault data Instrumental Seismicity Building parameters Site parameters Regional Seismic Hazard Earthquak e sources Seismic Wave Attenuation Earthquak e Recurrenc eModels Geodetic/ geophysical data Local Site Effects Site- specific Seismic Hazard Seismic Risk Index Ambrasey s Boore et al. Campbell Sadigh et al. Model 3 Model 2 Model 1 Earthquake Engineering Geotechnical Engineering Earthquake Seismology Geology & Geophysics Civil Engineering Vulnerability of the site Site-specific Spectral Hazard Seismic Hazard and Risk

4. (McCalpin and Nelson, 1996)

5. (McCalpin, 1996)

6. Probabilistic Seismic Hazard Assessment Deterministic Site specific analysis Scenario Based models Poissonian Models Renewal Models Seismic Hazard Assessment Hybrid Models

7. Seismic Hazard in the Catalan Coastal Ranges

8. Seismic Hazard in the Catalan Coastal Ranges Probabilisitic seismic hazard maps for various return periods. Earthquake occurrence is based on a Poissonian model.

9. Seismic Hazard in the Catalan Coastal Ranges

10. Seismic Hazard in the Catalan Coastal Ranges

11. Seismic Hazard in the Catalan Coastal Ranges Maps showing the difference between the renewal and the poissonian models at various return periods in terms of PGA (in cm/sec 2 ). The influence of the paleoseismic data become more visible at larger return periods.

12. Uncertainties In General: uncertainties may be divided in two categories: Uncertainties due to the lack of sufficient data these can be improved with additional data Uncertainties due to the lack of understanding of the phenomena additional data may not necessarily improve the understanding In Paleoseismology: uncertainties may be grouped into two: Analytical and/or numerical uncertainties Uncertainties related to the interpretation of data and/or observations

13. Preferred sequence of paleoseismic investigations Regional Scale (thousands of km 2 ) remote sensing, aerial photo’s, geological mapping, geophysical investigations and other background knowledge Local Scale (a few km 2 ) geomorphic mapping, Quaternary stratigraphic framework Site Scale (1 hectare to a few m 2 ) geophysics (shallow depth/high resolution) fault-zone trenching other detailed observations and data collection

14. Stage 1: Regional scale investigations that are dependent on the rate of deformation/tectonic setting and the background knowledge Stage 2: Local scale investigations and the site selection for detailed analysis Stage 3: Extrapolation of the observations that are made at a site scale to the entire fault. Stage 4: Identification of the paleoearthquake(s) based on the diagnostic criteria Stage 5: Dating techniques used for the age determination of the paleoearthquake(s) Stage 6: Paleoearthquake size estimate and the recurrence interval Paleoseismological interpretation process goes through the following stages:

16. UNIPAS acts as a link between the paleoseismic data and seismic hazard assessment Paleoseismic data UNIPAS Seismic hazard assessment

18. Paleoseismic Quality Factor The logic-tree analysis used in the paleoseismic interpretation process may be interfaced with the logic-tree analysis in the seismic hazard assessments through Paleoseismic Quality Factor (PQF). PQF is expressed by the following: PQF = P es x C ri where, P es is the probability of the preferred end-solution in the logic-tree analysis for the paleoseismic investigation and C ri is a correction term for the relative level of importance of the investigation in seismic hazard analysis.

19. Level of importance of the paleoseismic investigation in seismic hazard assessment The relative levels of importance may be grouped into five categories: Level 1: Site-specific seismic hazard analysis (SHA) Level 2: Regional probabilistic seismic hazard assessment Level 3: Input as seismotectonic sources in probabilistic SHA Level 4: Identifying the earthquake potential of the fault (zone) Level 5: Determining if the fault (zone) is active (i.e. observable co-seismic slip during the Holocene)

20. PQF is the connecting link between the logic-tree for paleoseismic data and the logic-tree for seismic hazard assessment Logic-tree for paleoseismic data PQF Logic-tree for seismic hazard assessment

21. (McCalpin and Nelson, 1996)

22. (Wells and Coppersmith, 1994)