Goal of the IGCP n.382 project Seismotectonics and Seismic Hazard Assessment of the Mediterranean Basin (SESAME, 1996-2000) is to produce a uniform seismotectonic zonation and seismic hazard assessment for the Mediterranean region. The project aims to increase the use of geological evidence in seismic hazard assessment by adopting a uniform probabilistic seismotectonic approach to compute seismic hazard throughout the Mediterranean and by incorporating geological evidence to supplement the historical record of seismicity in building a statistical model of seismogenic sources. The SESAME strategy is based on the integration and coordination of national, multi-national and regional programs operating in the Mediterranean.

Programs and test-areas for multi-national seismic hazard assessment have been active in different areas of the Mediterranean area: Ibero-Maghreb, central-northern Europe, Pannonian Basin, Adriatic Sea, Middle-East, Caucasus, Greece and Turkey. In coordination with the Global Seismic Hazard Assessment Program (ILP, ICSU, UN/IDNDR) and with the European Seismological Commission, SESAME has set up a schedule for the standardization of data bases, assessment methodology and hazard maps, and for the integration of the regional results into a homogeneous source zones and hazard mapping for the whole Mediterranean basin. The GSHAP (1992-1998) is now finished and the volume of regional reports and the global map have now been published (list of publications enclosed), while SESAME and the Working Group on Seismic Hazard of the European Seismological Commission (ESC/WG-SHA) will continue until the year 2000 for the Mediterranean area. The work is conducted in three phases:

1. 1996-97: the aim and activities of SESAME, the ESC/WG-SHA and GSHAP coincided; regional mapping of source zones and hazard were conducted in the different test-areas; in 1997 the regional results were presented at the 29th IASPEI Assembly (Thessalonicki, 8/97).
2. 1997-98: the intermediate goal of merging the regional hazard results into a preliminary regional PGA map was reached at the 26th ESC Assembly (Tel Aviv, 8/98), making possible to identify regions requiring further work and to set up a common stategy for Phase III.
3. 1998-2000: construct a homogeneous model of source zones for the whole Mediterranean and compute for the first time a suite of regional hazard maps in spectral parameters.

The present report summarizes the progress and cooperation in regional seismic hazard assessment, the achievements and specific activities/meetings of SESAME in 1999, the plans for the final year 2000, the 1999 budget and the main publications.

SHA in the Mediterranean area is coordinated under a number of regional, multi-national and national initiatives. Here we first describe the progress in the different areas, then summarize the work done toward achieving a basic level of unification in the whole Mediterranean. All details on activities in previous years are found in the SESAME report 1996-97 and 1998.

Minor changes have been made with respect to the GSHAP implementation in Central-Northern Europe, coordinated by the GFZ Regional Centre in Potsdam and including the territory north of 46°N. The seismic hazard for France has now been completed also south of 46°N and a second hazard zonation is now available for Poland, Czech Republic and Slovakia, coordinated by Prague University. (Grünthal et al., 1999a).

This project, coordinated by CSIC in Barcelona, includes Spain, Portugal, Morocco, Algeria and Tunisia. The catalogue, homogeneous zoning and SHA map were completed in 1997-98. (Jimenez et al., 1999).

This project includes all countries bordering on the Adriatic Sea (Italy, Switzerland, Austria, Slovenia, Croazia, Albania, Greece) coordinated by OGS of Trieste. A final iteration on the source zone model and the seismic hazard was conducted in Pisa (2/98; sponsored by SESAME), and the final model hazard results presented at the 1998 ESC assembly (Tel Aviv, 8/98). (Slejko et al., 1999).

The IGCP-SESAME and the UNESCO/USGS RELEMR are coordinating their activities toward a unified hazard mapping for the whole area (Turkey, Syria, Lebanon, Cyprus, Israel, Jordan, Egypt, Palestine, Saudi Arabia and Arabian Peninsula). Several planning and review meetings have been held so far in the area. In 1996 and 1997 SESAME organized two Training workshops on seismotectonics and seismic hazard analysis in the Eastern Mediterranean countries (Cairo, 12/96, 12/97). RELEMR organized workshops and special sessions dedicated also to hazard assessment in Cyprus (12/96), Thessalonicki (8/97) and Cyprus (10/97). Following this last meeting, joint SESAME/RELEMR activities were conducted in 1998 with the aim of producing a preliminary regional map of SHA, starting from existing regional PGA maps, and to verify the feasibility of a common strategy for future regional zoning. During the winter 1998, all existing hazard maps for the area were transferred to ETH Zurich, digitized and joined into a common geographic gridding. This first product was then critically analyzed by all contributing countries in Amman (5/98; sponsored by SESAME), with the aim to homogeneize the maps and smooth border discontinuities. After a second mapping iteration, the final preliminary map for the Near East was presented and discussed in Tel Aviv (8/98; sponsored by SESAME). A third workshop was organized by RELEMR in Istanbul (10/98), where a new strategy to build a commont earthquake catalogue, source zones and common hazard has been established for the whole region. In 1999, regional integration in hazard assessment was the main goal of meetings in Tehran (5/99) and Cyprus (10/99). (Grünthal et al., 1999b).

The project includes the Caucasian Republics (Armenia, Ukraine, Georgia, Turmenistan, Azerbaijan), Russia, Iran and Turkey. The coordinated catalogue, homogeneous zoning and SHA map were completed in 1997. (Balassanian et al., 1999).

The JIPE of Moscow is coordinating the seismic hazard mapping for the whole FSU territory. This five-year program, initiated before the FSU break-up and interrupted during the period of more intense political turmoil, has been restarted, leading to the compilation of the seismic catalogue and the SHA, using for the first time a probabilistic approach. Technical workshops are held routinely in Moscow. The whole area has been subdivided in five blocks, and the final catalogue, the model of source zones and lineaments and the hazard maps were released in early 1998. (Ulomov et al., 1999).

The EU-QSEZ-CIPAR project includes the countries of the Circum-Pannonian basin: Hungary, Romania, Slovania, Croatia, Albania in addition to Italy and UK. While the aim of this independent project was to produce a deterministic hazard assessment for the region, a specific source zoning (1997) and probabilistic hazard assessment (1998) were produced by BGS, Edinbourgh, for comparison with the deterministic results and for inclusion in SESAME and GSHAP. (Musson, 1999).

The official national hazard map of Greece has been contributed to the SESAME Mediterranean map (see below), while a new schedule to produce a national source zone model (not yet existing) and a new hazard map adjusted in critical border areas has been now established for 1999 by the groups in Thessalonicki and Athens.

The Kandilli Observatory of Istanbul has represented Turkey in the activities of the Caucasus and Eastern Mediterranean projects. Following the evaluation of the preliminary Mediterranean map (see below), a revised zoning and hazard maps are being produced to correct discrepancies in the Aegean and Eastern Anatolia border areas. (Erdik et al., 1999).

During 1997-98 the GFZ of Potsdam lead the efforts to collect and fit together the SHA maps derived in the individual regional projects described above. The preliminary PGA map includes the contributions of Ibero-Maghreb, Adria, Central-Northern Europe, Northern Eurasia, Caucasus, Greece, Turkey and Circum Pannonian and is accompanied by a compilation of the individual source zones. The draft maps were presented and discussed at the 1998 ESC assembly (Tel Aviv, 8/98) during the SESAME special events. The Near-East map was presented separately. In 1999 the first joint maps were produced (see figures) and published (Gruenthal et al., 1999b). The production of the unifiend source zone models is the key goal for 2000 (see below).

Two technical workshops were organized in the Eastern Mediterranean, within the regional framework described above. One was supported by SESAME.

1. workshop in Tehran (3^rd International conference on seismology and earthquake engineering, May 17-19, 1999); SESAME funding 2,000$; participants from the whole Near East region.
2. workshop in Cyprus (10/99) for the coordination of regional hazard mappin; May 4-7; participants from Israel, Cyprus, Palestine, Jordan, Egypt, Lebanon, Turkey, US

In addition, SESAME sponsored a working meeting of the coordinators of the different regional test areas in occasion of the IUGG General Assembly in Birmingham (7/99) and the traveling expenses for scientists from the Mediterranean basin (i.e. Libya) to work on the unification of the regional SHA map conducted at SED/ETHZ.

Following the strategy decided in TelAviv (8/97), SESAME and the ESC/WG-SHA are proceeding with the following 5 steps program:

1. The draft PGA map obtained by the compilation and fit of different regional PGA maps has refined and smoothed to produce a reference PGA map for the Mediterranean and included in the global GSHAP map, under the leadership of GFZ and SED/ETHZ, was completed in October 1999 (Grünthal et al., 1999b).
2. The EU-sponsored BEECD project has finalized in October 1998 the compilation of the first homogeneous European catalogue geared to hazard computation; this catalogue will be extended by the year 2000 to cover more areas of the Mediterranean, under the guidance of the IRRS of Milan. In parallel, the RELEMR group has started the merging of national databases in the Near East to compile a regional catalogue.
3. The first SESAME product has been a compilation of the source zones obtained in the different regions. We are now preparing the first homogeneous model of seismogenic sources for the whole Mediterranean by joining the existing zones as derived in the individual SESAME regions, design new zones in the border areas between different regions and compute the seismicity parameters from one of the two regional catalogues in the border region (using catalogues as they have been used in the individual areas ), design source zones and associated parameters in the areas where these are not available (parts of Near East, Libya). Concerns are uniform criteria to deal with size and dimension of source zones, relation to active tectonic features, characterization of the seismic statistics in the zones, back-ground and diffuse seismicity, across-boundary continuity.
4. One of the remaining elements of discontinuity in the Mediterranean is the adoption of different attenuation laws and related uncertainties in different areas of the Mediterranean. SESAME is now selecting a suite of attenuation laws for different tectonic domains in the region.
5. The final SESAME goal for September 2000 will be a new generation of regional hazard for the Mediterranean computed in uniform fashion from the regional catalogue, source zones model and attenuation laws. A suite of maps will be produced covering a range of spectral responses.

A 1-year contract, supported by SED/ETHZ, has been allocated to M.J. Jimenez of CSIC, Barcelona, to complete the work, in cooperation with other European and Mediterranean centers. The planned schedule calls for the first model to be presented At the EGS 2000 Assembly (Nice, April 27, 2000), to be finalized in a technical workshop in Slovenja (Poljce, May 22-24, 2000). The final source models and hazard results will be presented at the ESC 2000 General Assembly (Lisbon, September 13, 2000).

The regional reports are now published in the GSHAP volume, printed in late 1999 by Annali di Geofisica and now in distribution. All reports, databases, catalogues, procedures, maps and results are now loaded on the web site http://www.seismo.ethz.ch/GSHAP. The global map was released with a press conference at AGU (Dec. 1999) and reviewed very favourably by ABC, CNN, EOS, Discovery. The map has been printed in 11000 copies by USGS and a second print will be done in March, due to high demand. The Annali volume was printed in 3000 copies.

The SESAME budget for 1999 was of 6,250$. It was used as seed money to support the workshops in Tehran (2,000$) and Birmingham (1,500$), and the travel expenses connected with the compilation of the regional map of seismic source zones (2’000$). Expenses have been anticipated directly from the SED, Zurich.

The plan for the final SESAME year 2000 (see above) is to use the IGCP contribution to support the participation of scientists from the Mediterranean basin in the activities planned for the preparation of the final seismic sources model and the regional hazard assessment maps. Regional workshops are scheduled in Nice (EGS, 27/4/2000; 1’500$), Slovenja (Seismicity modeling in seismic hazard mapping, May 22-24, 2000; 2’000$), and Lisbon (ESC, September 13, 2000; 2’000$).

The SESAME request for the final year 2000 is of 5’500$.

Report prepared on February 3, 1999, by Domenico Giardini & S. Sellami, SED/ETHZ