USING GIS AND EARTHQUAKE SCENARIOS FOR THE ASSESSMENT OF EMERGENCY RESPONSE IN CASE OF A STRONG EARTHQUAKE. AN APPLICATION IN THE URBAN AREA OF THESSALONIKI, GREECE

The aim of this paper, which is part of the M.Sc Thesis of the first author, is an initial attempt for the assessment of the emergency response through the road network of the Urban Area of Thessaloniki (UAT) after a strong earthquake. The areas of the road network that are to become inaccessible either due to partial collapse of buildings or due to destruction of the road axes by rupture zones, are detected. The inaccessible parts are determined for the cases of three earthquake scenarios using the values of the Peak Ground Acceleration (PGA), which were calculated for about 6000 points over the UAT, as well as spatial overlay tools of a GIS. In the end, by applying network analysis and according to the situation of the network after the earthquake, the possibility of movement of the fire engines and ambulances was studied and least cost routes from ambulance stations to UAT hospitals were tracked

THE ACCELEROMETRIC NETWORK OF THE INDES-MUSA PROJECT IN THE KALOCHORI AREA: CONFIGURATION, DOCUMENTATION AND PRELIMINARY DATA INTERPRETATION

Ένα δίκτυο επτά επιταχυνσιογράφων στην επιφάνεια του εδάφους και σε κατασκευές εγκαταστάθηκε πρόσφατα στην ευρύτερη περιοχή Καλοχωρίου, δυτικά της Θεσσαλονίκης, στο πλαίσιο του ερευνητικού έργου INDES-MUSA ως τμήμα πολυπαραμετρικού δικτύου καταγραφής της σεισμικής κίνησης και της εδαφικής υποχώρησης της περιοχής. Το δίκτυο περιλαμβάνει σταθμούς εγκατεστημένους στην επιφάνεια του εδάφους και στην κορυφή τυπικών κατασκευών εντός αστικών υποσυνόλων καθώς και ένα σταθμό ελευθέρου πεδίου. Όλοι οι σταθμοί έχουν τεκμηριωθεί καταλλήλως, λαμβάνοντας υπόψη τα ιδιαίτερα χαρακτηριστικά της κάθε εγκατάστασης καθώς και τα χαρακτηριστικά της εδαφικής δομής, όπως αυτά εκφράζονται από την κατανομή με το βάθος της ταχύτητας διάδοσης των διατμητικών κυμάτων σε κάθε θέση. Παρουσιάζονται καταγραφές του δικτύου επιταχυνσιογράφων από τριαντά εννιά σεισμούς και δίνεται η διαδικασία διόρθωσης που εφαρμόστηκε στις πρωτογενείς χρονοϊστορίες επιτάχυνσης κατά το στάδιο επεξεργασίας και αποθήκευσης των σημάτων. Τέλος, παρουσιάζονται προκαταρκτικές συγκρίσεις τιμών μέγιστης εδαφικής επιτάχυνσης μεταξύ σταθμών εντός οικιστικής ζώνης και ελευθέρου πεδίου καθώς και συγκρίσεις φασματικών λόγων οροφής κατασκευών και βάσης με σκοπό την προκαταρκτική εκτίμηση των θεμελιωδών δυναμικών χαρακτηριστικών των ενοργανωμένων κατασκευών. Τα παραπάνω δεδομένα καταγραφών και τεκμηρίωσης είναι διαθέσιμα μέσω της διαδικτυακής πλατφόρμας Web-GIS του έργου INDESMUSA. A network of seven accelerometric stations on both ground surface and structures has been recently installed, as part of a multi-sensor network for monitoring seismic motion and ground subsidence in the broader area of Kalochori, west of Thessaloniki in Northern Greece, within the INDES-MUSA project. This network includes ground installations within the urban area, structural stations on top of structures and a freefield station away from the building stock. The documentation of stations is presented including shear wave velocity profiles of the subsoil at each location. A set of thirtynine earthquakes recorded so far by the accelerometric network is reported, followed by data processing procedures performed in the acquired waveforms. Comparisons of the processed earthquake recordings are presented referring to (a) the urbanground and the free-field stations in terms of peak ground acceleration, indicating amplification trends of ground motion, and (b) the structural and the nearby urban ground stations by means of top-to-base ratios in the frequency domain, towards a preliminary identification of the fundamental vibrational characteristics of the instrumented structures. The processed acceleration data are available through the INDES-MUSA Web-GIS portal

THE ACCELEROMETRIC NETWORK OF THE INDES-MUSA PROJECT IN THE KALOCHORI AREA: CONFIGURATION, DOCUMENTATION AND PRELIMINARY DATA INTERPRETATION

Ένα δίκτυο επτά επιταχυνσιογράφων στην επιφάνεια του εδάφους και σε κατασκευές εγκαταστάθηκε πρόσφατα στην ευρύτερη περιοχή Καλοχωρίου, δυτικά της Θεσσαλονίκης, στο πλαίσιο του ερευνητικού έργου INDES-MUSA ως τμήμα πολυπαραμετρικού δικτύου καταγραφής της σεισμικής κίνησης και της εδαφικής υποχώρησης της περιοχής. Το δίκτυο περιλαμβάνει σταθμούς εγκατεστημένους στην επιφάνεια του εδάφους και στην κορυφή τυπικών κατασκευών εντός αστικών υποσυνόλων καθώς και ένα σταθμό ελευθέρου πεδίου. Όλοι οι σταθμοί έχουν τεκμηριωθεί καταλλήλως, λαμβάνοντας υπόψη τα ιδιαίτερα χαρακτηριστικά της κάθε εγκατάστασης καθώς και τα χαρακτηριστικά της εδαφικής δομής, όπως αυτά εκφράζονται από την κατανομή με το βάθος της ταχύτητας διάδοσης των διατμητικών κυμάτων σε κάθε θέση. Παρουσιάζονται καταγραφές του δικτύου επιταχυνσιογράφων από τριαντά εννιά σεισμούς και δίνεται η διαδικασία διόρθωσης που εφαρμόστηκε στις πρωτογενείς χρονοϊστορίες επιτάχυνσης κατά το στάδιο επεξεργασίας και αποθήκευσης των σημάτων. Τέλος, παρουσιάζονται προκαταρκτικές συγκρίσεις τιμών μέγιστης εδαφικής επιτάχυνσης μεταξύ σταθμών εντός οικιστικής ζώνης και ελευθέρου πεδίου καθώς και συγκρίσεις φασματικών λόγων οροφής κατασκευών και βάσης με σκοπό την προκαταρκτική εκτίμηση των θεμελιωδών δυναμικών χαρακτηριστικών των ενοργανωμένων κατασκευών. Τα παραπάνω δεδομένα καταγραφών και τεκμηρίωσης είναι διαθέσιμα μέσω της διαδικτυακής πλατφόρμας Web-GIS του έργου INDESMUSA. A network of seven accelerometric stations on both ground surface and structures has been recently installed, as part of a multi-sensor network for monitoring seismic motion and ground subsidence in the broader area of Kalochori, west of Thessaloniki in Northern Greece, within the INDES-MUSA project. This network includes ground installations within the urban area, structural stations on top of structures and a freefield station away from the building stock. The documentation of stations is presented including shear wave velocity profiles of the subsoil at each location. A set of thirtynine earthquakes recorded so far by the accelerometric network is reported, followed by data processing procedures performed in the acquired waveforms. Comparisons of the processed earthquake recordings are presented referring to (a) the urbanground and the free-field stations in terms of peak ground acceleration, indicating amplification trends of ground motion, and (b) the structural and the nearby urban ground stations by means of top-to-base ratios in the frequency domain, towards a preliminary identification of the fundamental vibrational characteristics of the instrumented structures. The processed acceleration data are available through the INDES-MUSA Web-GIS portal

SEISIMPACT-THES: A SCENARIO EARTHQUAKE AFFECTING THE BUILT ENVIRONMENT OF THE PREFECTURE OF THESSALONIKI

In the framework of the "SEISIMPACT-THES" project (Koutoupes et al., 2004; Savvaidis et al., 2004) a GIS database has been designed to include information on a wide range of components related to seismic risk within the broader area of the prefecture of Thessaloniki. One of these components refers to the distribution of strong ground motion produced by large earthquakes and the ability of a potential future user of the database to retrieve information regarding the distribution of strong ground motion from past destructive earthquakes in the area of Thessaloniki, as well as relative information for realistic future scenario earthquakes in the same area. The selection of future scenario earthquakes that may affect this urban region of interest is based on a combined review of historical data, previous probabilistic and deterministic hazard assessments, seismotectonic and microseismicity studies, relocated seismicity in northern Greece and the experience gained from worldwide research. In this study we present the results from hypothetical rupture of one fault that is located at the suburbs of the city, the Asvestochori fault. Empirical relations applicable to Greece (Papazachos & Papazachou 2003), as well as seismicity information are combined to determine the dimensions of the scenario earthquake source. Strong ground motion for the selected scenario is simulated using the stochastic method for finite faults (Beresnev and Atkinson, 1997). Uncertainties due to unknown parameters such as the rupture initiation point and the distribution of slip on the fault plane are taken into account by examining a large number of random scenarios. The average values from these multiple scenarios are then used to compile maps of strong ground motion parameters (e.g. peak ground acceleration and spectral acceleration). Although the examined scenario earthquake is moderate in size (Mw 5.2), the level of the resulting strong ground motion parameters is indicative of the potential destructiveness of the examined source. Due to the simplicity in the underlying assumptions of the stochastic method, the results of this study are a first-order approximation to the problem of defining expected shaking in the wider area of Thessaloniki. Other strong motion simulation methods of more deterministic character will also be applied for the same purpose in the framework of the SEISIMPACT-THES project

USING GIS AND EARTHQUAKE SCENARIOS FOR THE ASSESSMENT OF EMERGENCY RESPONSE IN CASE OF A STRONG EARTHQUAKE. AN APPLICATION IN THE URBAN AREA OF THESSALONIKI, GREECE

The aim of this paper, which is part of the M.Sc Thesis of the first author, is an initial attempt for the assessment of the emergency response through the road network of the Urban Area of Thessaloniki (UAT) after a strong earthquake. The areas of the road network that are to become inaccessible either due to partial collapse of buildings or due to destruction of the road axes by rupture zones, are detected. The inaccessible parts are determined for the cases of three earthquake scenarios using the values of the Peak Ground Acceleration (PGA), which were calculated for about 6000 points over the UAT, as well as spatial overlay tools of a GIS. In the end, by applying network analysis and according to the situation of the network after the earthquake, the possibility of movement of the fire engines and ambulances was studied and least cost routes from ambulance stations to UAT hospitals were tracked

A geophysical survey in the archaeological site of Archontiko, Yannitsa

The ancient settlement of Archontiko is 4.5 km NW of ancient Pella in North Greece (Figure 1). The findings showed that the area was first occupied by the end of the Iron Age, i.e. 650-550 B.C. Also, showed that the topographic table of Archontiko was a major settlement of the Yannitsa province due to its concessive position by the main roads of Macedonia (Chrysostomou A. and Chrysostomou P., 1993). At the upper layers of the ruins, findings of the Roman and Byzantine times were also unearthed. The geophysical methods have been used in order to detect and map antiquities in various sites in Greece (e.g., Tsokas et al., 1994; 1995; Sawaidis et al., 1999). The resistivity mapping employing the twin probe array, the total magnetic field variations, the airborne photos and the Ground Probing Radar are the most popular methods in this respect. However, almost all geophysical methods can be used to tackle specific problems. From 1992 till 1994, many geophysical surveys were carried out in the area of Archontiko to collect mainly magnetic data. Resistivity measurements were also conducted in a small part of the area. The data presented in this study cover the northern side of the topographic table of Archontiko and they were collected during two campaigns during the summer of the years 1992 and 1993 (Figure 2)

DATA BASE DEVELOPMENT AND EVALUATION OF EARTHQUAKE DAMAGE REPORTS UNDER THE SEISIMPACT-THES SYSTEM

One of the scopes of the SEISIMPACT-THES project is to organize into digital form and evaluate the records of reported damage, related to the occurrence of the 1978 Thessaloniki earthquake (Mw=6.5). For the exploitation of these data, an advanced Information System is under development that will include:• A properly designed database• A Geographic Information System containing all the necessary data (after digitization and corrections) enriched with more recent data, as well as topographic, geological and geophysical data of the region (metropolitan area of Thessaloniki)• A model system of accessing the above via the web and mobile devicesThe basic data for the implementation of the project are derived from the archives of the Agency for the Relief of Seismic Catastrophes in Northern Greece (YASBE). The data are included in the forms of inspection of buildings carried out in Thessaloniki shortly afterwards the 1978 earthquake. It is estimated that there are roughly 63,000 building inspection forms in the region of Thessaloniki. The exploitation of this rich database with the description on the damage that the buildings suffered will result in a complete electronic database properly standardized so that it can be linked to the geographic data of a Geographic Information System. The database structure will allow multiple queries and processes to study in depth the behavior of buildings in Thessaloniki, and its correlation with other geological, geophysical, geotechnical factor

A geophysical survey in the archaeological site of Archontiko, Yannitsa

The ancient settlement of Archontiko is 4.5 km NW of ancient Pella in North Greece (Figure 1). The findings showed that the area was first occupied by the end of the Iron Age, i.e. 650-550 B.C. Also, showed that the topographic table of Archontiko was a major settlement of the Yannitsa province due to its concessive position by the main roads of Macedonia (Chrysostomou A. and Chrysostomou P., 1993). At the upper layers of the ruins, findings of the Roman and Byzantine times were also unearthed. The geophysical methods have been used in order to detect and map antiquities in various sites in Greece (e.g., Tsokas et al., 1994; 1995; Sawaidis et al., 1999). The resistivity mapping employing the twin probe array, the total magnetic field variations, the airborne photos and the Ground Probing Radar are the most popular methods in this respect. However, almost all geophysical methods can be used to tackle specific problems. From 1992 till 1994, many geophysical surveys were carried out in the area of Archontiko to collect mainly magnetic data. Resistivity measurements were also conducted in a small part of the area. The data presented in this study cover the northern side of the topographic table of Archontiko and they were collected during two campaigns during the summer of the years 1992 and 1993 (Figure 2)