Browsing by Author "Dessales, Helene"

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    Construction history of the aqueduct of Nicaea (Iznik, NW Turkey) and its on-fault deformation viewed from archaeological and geophysical investigations
    (Elsevier, 2018-08-08) Benjelloun, Yacine; De Sigoyer, Julia; Dessales, Helene; Garambois, Stephane; Şahin, Mustafa; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Arkeologi Bölümü.; 0000-0001-5153-1918; E-1041-2019; 35318789000
    The aqueduct of Nicaea (modern Iznik, in northwestern Turkey) was studied for the first time using combined building stratigraphy, typology of construction techniques and subsurface geophysics. The analysis of the different materials and building techniques used allowed us to identify more than forty individual stratigraphical units on the section investigated, using thirteen specific techniques. The comparison of certain masonries with analogous techniques visible in the defensive walls of the city and our stratigraphical interpretations led us to propose a chronology of the construction divided into nine phases. Some of these rebuildings seem linked to war and earthquake damage. The aqueduct was originally built in the first centuries AD using a framework of terracottas and limestone rubble. Later on, two functional terracotta structures were added and the spews was extensively rebuilt. In a second period, the early facing was replaced by well-cut travertines. Significant rebuilding occurred around the 11th century when the city was attacked by the Turks. The last modifications date from the Lascarid period and are probably linked to the construction of a second defensive wall in the 13th century, which cuts the western end of the aqueduct. Geophysical acquisitions on the eastern section of the aqueduct evidenced a vertical offset of the building. The location of these offsets correlate well with the trace of a normal fault which historical activity was not suspected before. These kind of multidisciplinary approaches are powerful tools to study active tectonics and their impact on past societies.
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    Historical earthquake scenarios for the middle strand of the north anatolian fault deduced from archeo-damage inventory and building deformation modeling
    (Seismological Soc Amer, 2021-01-01) Benjelloun, Yacine; de Sigoyer, Julia; Dessales, Helene; Baillet, Laurent; Gueguen, Philippe; Şahin, Mustafa; ŞAHİN, MUSTAFA; Bursa Uludağ Üniversitesi/Fen‐Edebiyat Fakültesi/Arkeoloji Bölümü; 0000-0001-5153-1918; E-1041-2019
    The city of znik (ancient Nicaea), located on the middle strand of the North Anatolian fault zone (MNAF), presents outstanding archeological monuments preserved from the Roman and Ottoman periods (first to fifteenth centuries A.D.), bearing deformations that can be linked to past seismic shaking. To constrain the date and intensity of these historical earthquakes, a systematic survey of earthquake archeological effects (EAEs) is carried out on the city's damaged buildings. Each of the 235 EAEs found is given a quality ranking, and the corresponding damage is classified according to the European Macroseismic Scale 1998 (EMS-98). We show that the walls oriented north-south were preferentially damaged, and that most deformations are perpendicular to the walls' axes. The date of postseismic repairs is constrained with available archeological data and new C-14 dating of mortar charcoals. Three damage episodes are evidenced: (1) between the sixth and late eighth centuries, (2) between the nineth and late eleventh centuries A.D., and (3) after the late fourteenth century A.D. The repartition of damage as a function of building vulnerability points toward a global intensity VIII on the EMS-98. The 3D modeling of a deformed Roman obelisk shows that only earthquakes rupturing the MNAF can account for this deformation. Their magnitude can be bracketed between M-w 6 and 7. Our archeoseismological study complements the historical seismicity catalog and confirms paleoseismological data, suggesting several destructive earthquakes along the MNAF, since the first century A.D. We suggest the fault might still have accumulated enough stress to generate an M-w 7+ rupture.