different tsunamogenic earthquakes occurred in the area of Maliakos Gulf during the 5th and 3rd centuries BC(Papaioannou et al.

Transcript

1 On the basis of the different descriptions ΣΕΙΣΜΙΚΕΣ of Thucydides ΚΑΤΑΣΤΡΟΦΕΣ and Strabo και ΕΝΕΡΓΑ and several ΡΗΓΜΑΤΑ, inconsistencies that characterize the Η two σημασία texts, τους we suggested στη θεμελίωση that possibly Τεχνικών two Έργων different tsunamogenic earthquakes occurred in the area of Maliakos Gulf during the 5th and 3rd centuries BC(Papaioannou et al., 2005) The coastal area of Maliakos gulf and Oreon Straight are controlled by many active E-W trending faults (or segments) associated with large earthquakes: 420 BC, 511, 544, 1740, and 1758.

2 Atalanti Fault Atalanti Island Atalanti Fault

3 So severe were the shocks that in many parts of Greece the sea actually swept away and destroyed some cities lying on the coast, while in Lochris the strip of land forming a peninsula was torn through and the island of Atalante was formed. Diodorus Siculus, 1st century AD In the neighbourhood of the island of Atalante, which lies off the coast of Opuntian Locris, there was a similar inundation, which carried away part of the Athenian fort there and wrecked two ships that had been drawn up on the shore. Thucydides, contemporary account The sea was receded and flood followed along the coast of North Euboea....In my opinion, the cause of the phenomenon was this: where the earthquake was most violent, the sea receded and was then pushed back with even greater violent, thus bringing about a flood. Such thing would not have happened without an earthquake (Definition of Seismogenic Sea Wave by Thucydides 5th century B.C.)

4 Η σημασία τους στη ATALANTI θεμελίωση Central Τεχνικών Greece Έργων 1894 M=7.0 and 6.7 eqs

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6 Butrint Archaeological site ( SW Albania-Greek border )

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8 Butrint ( SW Albania ) ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ,

9 Location map of Greek Thrace and the main Roman archaeological sites. ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ,

10 EDIRNE km Infrared LANDSAT image with the main faults of the area.

11 Surface ruptures that were revealed after the archaeological excavation. ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ,

12 Surface ruptures that were revealed after the archaeological excavation.

13 Log of DOX-2-2 trench. The fault has formed a trench with net vertical displacement of 1.1 m, which reaches an extreme of 1.9 m (right part of the log). S 75 E N 75 W S N EXPLANATION Filling deposits 1 Brown colored paleosoil S 85 E N 85 W S 35 E N 35 W 2 Red colored silt 3 Yellow-brown colored silty clay 4 White colored caliche 1 5 Green colored marl Brown colored silty clay 1 m White colored caliche Green colored marl Ceramic and sample location 1 m Fault and crack DOX-2-2 trench

14 ΣΕΙΣΜΟΣ ΘΕΣΣΑΛΟΝΙΚΗΣ 1978, Μs=6.5

15 Δορυφορική φωτογραφία από Landsat-5 image dashed red line=the main fault και σκαρίφημα από γεωλογική χαρτογράφηση (Μουντράκης) του Ρήγματος στην περιοχή Βόλβης (Θεσσαλονίκη) Detailed mapped fault ruptures (after Mercier et al, Mountrakis et al etc)

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17 Mygdonia basin (trench GER 1) paleosoils liquefied sands

18 Results from Mygdonia basin Recurrence intervalfor large (Ms 6.5+) events along the southern fault zone is ca. 900 years. Slip rateranges from 0.26 to 0.7 mm/yr for different strands along the fault zone.

19 Mygdonia basin Macedonia - Northern Greece Thessaloniki 1978 eq Ms=6.5

20 ΜΟΡΦΟΤΕΚΤΟΝΙΚΗ Για τον υπολογισμό των μορφοτεκτονικών δεικτών χρειάστηκε η ψηφιοποίηση των ισουψών καμπύλων της περιοχής μελέτης και η απεικόνισή τους σε τρισδιάστατα μοντέλα εδάφους (Digital Elevation Models) DEM. Για την ψηφιοποίηση χρησιμοποιήθηκαν οι χάρτες της ΓΥΣ (φύλλα Θεσσαλονίκης, Θέρμης, Επανομής, Ζαγκλιβερίου, Πολυγύρου και Βασιλικών) με κλίμακα 1: καθώς και οι αντίστοιχοι χάρτες τουιγμε. Για την επεξεργασία τους στον υπολογιστή χρησιμοποιήθηκε το πρόγραμμα ArcGIS 9.1 και τα υποπρογράμματα 3D-Analyst, Topology και Spatial Analyst. ΖΕΡΒΟΠΟΥΛΟΥ Διδ. Διατρ.

21 ΟΔΟΣ ΚΥΠΡΟΥ

22 The Stratoni active fault is a large normal fault located at the eastern part of Chalkidiki peninsula in northern Greece. It extends for about 15km on land and possibly 10-15km eastern submarine. It is part of the large NW SE trending zone of active fault systems. The fault is associated the 1932 earthquakes Ms 7.0, 6.8, 6.2, 6.0

23 The fault is associated with the large 1932 Ierissos earthquake, of magnitude , which caused widespread damages, as well as extensive surface rupturing

24 STRATONI Northern Greece 1932 Ms 6.9 ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ, 1,8-2,0m Co-seismic fault traces with vertical offset 1-2m, while they were enlarged by shaking and gravitational forces (heave 0.6-4m).

25 Hypsometric Integral=0.36 The fault divides the area geomorphologically into two different regions: the northern (mountains-footwall) and the southern (hills-hanging wall). (granites+gneisses/amphibolites)

26 A 0.5 to 1.5 m coast subsidence and a weak tsunami have been reported. Accurate measurements by the Greek Navy (Hydrographic Service, 1932) have shown mmaximum co-seismic displacement at the Ierissos gulf.

27 STRATONI FAULT-EASTERN ΣΕΙΣΜΙΚΕΣ CHALKIDIKI-NORTHERN ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ GREECE ΡΗΓΜΑΤΑ, Η σημασία (DEM) τους στη θεμελίωση Τεχνικών Έργων triangular facets

28 S4 S3 S2 S1 Stratoni fault can be divided into FOUR (4) main segments (S1,S2,S3, and S4), on the basis of structural characteristics and geomorphological expression

29 Α. Μιχαηλίδου MSc ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ,

30 WELLS & ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ, AMBRASEYS & PAVLIDES COPPERSMITH JACKSON et al., (2000) SRL=30km M w =6.8 M s =6.85 M s =6.82 Ms=7.0 SRL=30.9km SRL=40.27km SRL=44.67km MD=1.8m M=6,79 M=6.97 M=6.91 Ms=7.0 MD=2.14m MD=194cm MD=2.55m AD=0.3m M=6.44 Mmax SRL =7.08 Ms=7.0 AD=0.9m Mmax MD =7.16

31 Deterministic Seismic Hazard Assessment The maximum expected magnitude for the region is Mmax=7.11± T=275 yrs is the mean return period for Ms 7.0 For a 30kmx10km fault (potential earthquake source) and for the earthquake (design or controlling earthquake) that is expected to produce the strongest level of shaking and producing ground motion and deformation (surface rupture close to infrastructure) in the framework of the Deterministic Seismic Hazard Assessment (DSHA) the results are as follows: Ms=7.0 MD=2m AD=1m a=0.45g

32 Η ΠΡΟΕΚΤΑΣΗ ΤΟΥ ΣΕΙΣΜΙΚΟΥ ΡΗΓΜΑΤΟΣ ΣΤΟ ΔΡΟΜΟ ΠΑΛΑΙΟΧΩΡΙ-ΣΑΡΑΚΗΝΑ ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ, Co-seismic Ruptures

33 Concluding remarks Stratigraphic record shows three events with the 1981 event included Colluvial tectonostratigraphy shows surface rupturing events in the order of ~1m Mapping of trenches shows at least two events during the Holocene with the 1981 event excluded

34 KOZANI-GREVENA 1995 Eq Ms=6.6 Western Macedonia-NorthenGreece Ρύμνιο(δρόμος Κοζάνης-Λάρισας)

35 Servia Faults Western Macedonia-Northern Greece ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ, ΡΗΓΜΑ ΡΥΜΝΙΟΥ-ΠΑΛΑΙΟΧΩΡΙΟΥ-ΣΑΡΑΚΗΝΑΣ (ΑΠΟ ΤΗ ΓΕΦΥΡΑ ΤΟΥ ΡΥΜΝΙΟΥ, ΠΑΡΑΛΛΗΛΑ ΣΤΗΝ ΠΑΡΑΤΑΞΗ) HANGING WALL (HOLOCENE SCREE) ΠΛΕΥΡΙΚΑ ΚΟΡΗΜΑΤΑ (ΤΕΤΑΡΤΟΓΕΝΗ) Footwall ΑΝΕΡΧΟΜΕΝΟ ΤΕΜΑΧΟΣ

36 Fault Surface (Early Neogene) Η παλιά κατοπτρική επιφάνεια του σεισμικού ρήγματος Co-seismic Rupture Διακρίνεται η νέα επαναδραστηριοποίηση (απογύμνωση βράχου κατά D=10 cm)

37 ΕΠΙΦΑΝΕΙΑΚΕΣ ΔΙΑΡΡΗΞΕΙΣ Gravitational Cracks ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ,

38 Μουντράκης κ.α 1996 ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ,

39 ΚΑΤΟΛΙΣΘΗΣΗ ΣΤΟ ΧΩΡΙΟ ΚΕΝΤΡΟ LANDSLIDE TRIGGERED BY THE 1995 Eq

40 Κρατήρες άμμου (Λ. Πολυφύτου) sand volcano ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ, LIQUEFACTION ΦΑΙΝΟΜΕΝΟ ΡΕΥΣΤΟΠΟΙΗΣΗΣ

41 ΠΕΡΙΟΧΗ ΚΟΖΑΝΗΣ Ρύμνιο(γέφυρα) BRIDGE EMPARKMENT SUBSIDENCE 80 cm Liquefaction-induced ground subsidence of embankment (Kozani earthquake, 1995)

42 PAL-3 PALAEO- LIQUEFACTION «AΠΟΛΙΘΩΜΕΝΟ» ΗΦΑΙΣΤΕΙΟ ΑΜΜΟΥ 1 m FAULTS PALAEO -SEISMIC EVENTS ΑΛΜΑΤΑ ΡΗΓΜΑΤΩΝ -ΕΞΑΓΩΓΗ ΣΥΜΠΕΡΑΣΜΑΤΩΝ ΓΙΑ ΜΕΓΕΘΟΣ ΠΡΟΗΓΟΥΜΕΝΩΝ ΣΕΙΣΜΩΝ

43 Earthquake events from Palaeoseismological Research Northern Greece 1. Mygdonia Basin 2. Kozani-Grevena area Southern Greece 1. Eliki area 2. Kaparelli area Northern Greece yr yr (???) Southern Greece yr yr Northern Greece mm / yr mm / yr Southern Greece mm / yr mm / yr

44 Understanding active fault behavior Repeated seismic activity does not produce surface ruptures along the same fault strands. Fault activity seems to deviate from the Recurrence Interval predicted by past earthquake events. (characteristic in Eliki, Mygdonia, Atalanti etc) WHY?? Earthquake clustering (closely spaced earthquakes and periods of inactivity) Fault segment triggering ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ, A cluster of seismic events in Atalanti fault. Including the 1894 Ms=7.0 eq

45 FAULT PARAMETRES AS INPUT TO SHA Kozani Grevena (W. Macedonia) 1995 Ms = 6.6 Kaparelli Athens 1981 Ms = 6.4 Ierissos Northern Greece 1932 Ms 6.9 1,8-2,0m ΕΚΤΙΜΗΣΗ ΣΕΙΣΜΙΚΗΣ ΕΠΙΚΙΝΔΥΝΟΤΗΤΑΣ ΜΕ ΓΕΩΛΟΓΙΚΑ ΔΕΔΟΜΕΝΑ

46 7,5 ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ, 7,0 Ms 6,5 6,0 morphogenic ethqs 5,5 5,0 not morphogenic ethqs 4, geological fault length (km) Magnitude (Ms) versusgeological fault length (GFL). The dashed line represents a possible lower limit for geological fault length associated to normal active faulting as a function of the maximum expected magnitude. The curve also indicates the threshold for morphogenic earthquakes (sensu Caputo, 1993). S. Pavlides & R. Caputo, TECTONOPYSICS 2004

47 Earthquake Fault Ruptures of the ΣΕΙΣΜΙΚΕΣ broader Aegean ΚΑΤΑΣΤΡΟΦΕΣ Region και as ΕΝΕΡΓΑ Quantitative ΡΗΓΜΑΤΑ, Input to Seismic Η σημασία Hazard Assessment τους στη θεμελίωση Τεχνικών Έργων Map of the broader Aegean Region with the seismogenic faults (lines) and epicentres where coseismic surface ruptures are well documented Source parameters, such as rupture length, fault displacement (average and maximum) and rupture area compiled to develop empirical relationships versus earthquake magnitude. A fundamental problem was the accuracy of data, described and investigated by different authors S.Pavlides & R.Caputo, TECTONOPYSICS 2004

48 Histogram of the SRL to GFL ratio. The major peak indicates that the half of the historical earthquakes ruptured almost the entire neotectonic fault length as it could be estimated from geological, morphotectonic and palaeoseismological surveys. The second peak around 0.5, emphasise the existence of segmented faults which have not been entirely activated during documented past earthquakes.

49 ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ, Calculated regressions of Ms on SRL and of Ms on MVD, respectively: a) Magnitude -Surface Rupture Length Ms = 0.90 log(srl) b) Magnitude -Maximum Displacement Ms = 0.59 log(mvd) The correlation coefficient is 0.84 for the Ms/SRL regression equation and 0.82 for the Ms/MVD regression equation relative to 36 and 31 data, respectively. The confidence value is larger than 99% for both equations.

50 Ms Ms = 1.21 log(srl) Ms = 1.42 log(srl) ΣΕΙΣΜΙΚΕΣ ΚΑΤΑΣΤΡΟΦΕΣ και ΕΝΕΡΓΑ ΡΗΓΜΑΤΑ, surface rupture length (km) Magnitude (Ms) versussurface rupture length (SRL) Ms = 1.03log(SRL)+5.33 Papazach os (1989) Ms versus SRL Wells and Coppersmi th (1994) Ambrase ys and Jackson (1998) Ambrase ys and Jackson (1998) present research b a