Laboratoire Of Geographie Physique

Martigné-Briand, France

Laboratoire Of Geographie Physique

Martigné-Briand, France
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Evelpidou N.,National and Kapodistrian University of Athens | Karkani A.,National and Kapodistrian University of Athens | Kampolis I.,National and Kapodistrian University of Athens | Pirazzoli P.,Laboratoire Of Geographie Physique
Quaternary International | Year: 2017

A coastal and submarine geomorphological investigation took place in the coasts of eastern Attica, aiming to identify palaeoshorelines. Former sea-level positions were deduced from emerged and submerged tidal notches. Eight fossil shorelines were deduced in the study area; two emerged ones at about +24 ± 30 and +40 ± 30 cm, and six submerged ones at about −22 ± 30 (modern), −40 ± 30, −60 ± 30, −80 ± 30, −130 ± 30 and −460 ± 30 cm. It is worth mentioning that a rather different tectonic behavior may be distinguished between the south (AT1-AT5) and the north (AT10-AT28) part of the study area. © 2016 Elsevier Ltd and INQUA


Evelpidou N.,National and Kapodistrian University of Athens | Karkani A.,National and Kapodistrian University of Athens | Pirazzoli P.,Laboratoire Of Geographie Physique
Geologica Acta | Year: 2017

In this paper the tectonic behavior of Leukas and Meganisi islands (Ionian Sea) is examined through underwater research carried out in both islands. A possible Late Holocene correlation between coseismic subsidences is attempted and evidenced by submerged tidal notches in both islands. These subsidence events probably occurred after the uplift that affected the northernmost part of Leukas around 4 to 5ka BP. In conclusion, although the whole area was affected by a similar tectonic strain, certain coseismic events were only recorded in one of the two islands and in some cases they affected only part of the study area. © N. Evelpidou, A. Karkani, P. Pirazzoli, 2017 CC BY-SA.


Jousset P.,Bureau de Recherches Géologiques et Minières | Pallister J.,U.S. Geological Survey | Boichu M.,University of Cambridge | Buongiorno M.F.,Isituto Nazionale di Geofisica e Vulcanologia | And 14 more authors.
Journal of Volcanology and Geothermal Research | Year: 2012

Merapi volcano (Indonesia) is one of the most active and hazardous volcanoes in the world. It is known for frequent small to moderate eruptions, pyroclastic flows produced by lava dome collapse, and the large population settled on and around the flanks of the volcano that is at risk. Its usual behavior for the last decades abruptly changed in late October and early November 2010, when the volcano produced its largest and most explosive eruptions in more than a century, displacing at least a third of a million people, and claiming nearly 400 lives. Despite the challenges involved in forecasting this 'hundred year eruption', we show that the magnitude of precursory signals (seismicity, ground deformation, gas emissions) was proportional to the large size and intensity of the eruption. In addition and for the first time, near-real-time satellite radar imagery played an equal role with seismic, geodetic, and gas observations in monitoring eruptive activity during a major volcanic crisis. The Indonesian Center of Volcanology and Geological Hazard Mitigation (CVGHM) issued timely forecasts of the magnitude of the eruption phases, saving 10,000-20,000 lives. In addition to reporting on aspects of the crisis management, we report the first synthesis of scientific observations of the eruption. Our monitoring and petrologic data show that the 2010 eruption was fed by rapid ascent of magma from depths ranging from 5 to 30km. Magma reached the surface with variable gas content resulting in alternating explosive and rapid effusive eruptions, and released a total of ~0.44Tg of SO2. The eruptive behavior seems also related to the seismicity along a tectonic fault more than 40km from the volcano, highlighting both the complex stress pattern of the Merapi region of Java and the role of magmatic pressurization in activating regional faults. We suggest a dynamic triggering of the main explosions on 3 and 4 November by the passing seismic waves generated by regional earthquakes on these days. © 2012 Elsevier B.V.


Evelpidou N.,National and Kapodistrian University of Athens | Kampolis I.,National and Kapodistrian University of Athens | Pirazzoli P.A.,Laboratoire Of Geographie Physique | Vassilopoulos A.,Geoenvironmental Institute
Global and Planetary Change | Year: 2012

The recent rise in global sea level is causing the disappearance of an important geomorphological sea-level indicator, the tidal notch.Tidal notches have often been used in carbonate coasts for Quaternary and late Holocene sea-level reconstructions and estimation of tectonic movements, especially in uplifting areas. In this paper, we review the rates of tidal notch development, and examine the recent gradual depletion of this feature, during at least the last century, and its relation to the increasing rates of sea-level rise. Some examples of tidal notch development are provided with fossil submerged notches from Greece. Although tidal notches are no longer forming in the present-day mid-littoral zone, underwater marks on carbonate cliffs may still provide evidence of submerged tidal notches corresponding to former sea-level positions, or of recent vertical shoreline displacements of seismic origin. © 2012 Elsevier B.V.


Evelpidou N.,National and Kapodistrian University of Athens | Vassilopoulos A.,Geoenvironmental Institute | Pirazzoli P.A.,Laboratoire Of Geographie Physique
Marine Geology | Year: 2012

Detailed mapping along the northwestern coastline of Euboea has provided new evidence of colonization by Lithophaga lithophaga (L.) reaching about 3.8. m above the present biological MSL. Such marine biological marks, together with morphological notches, correspond to the occurrence of two sequences of Holocene vertical displacements higher than those reported by previous studies, on the central part of the southern coast and along the northern coast of the island. A well developed emerged notch is found at + 1.7 ± 0.1. m above present mean sea level, whereas the uppermost part of the lithophagid holes suggest a former emerged shoreline at least at + 3.8 ± 0.1. m. Radiocarbon AMS dating of Lithophaga shells found in their burrows, showed that the lower uplifted shoreline corresponds to a tectonic event (probably coseismic) apparently dated at 2200 a BP, while the higher shoreline corresponds to an older relative sea-level transgression, possibly of tectonic origin, apparently dated about 5570 a BP. The apparent radiocarbon age of lithophagid shells can be about 350 to 400. years older than the uplift event that exposed them, due to incorporation of host-rock carbon. Nevertheless, the two new paleoshorelines provide evidence that repeated uplift movements, greater than those reported by previous authors, occurred during the late Holocene, uplifting the western part of the island. © 2011 Elsevier B.V.


Evelpidou N.,National and Kapodistrian University of Athens | Pirazzoli P.A.,Laboratoire Of Geographie Physique | Vassilopoulos A.,Geoenvironmental Institute | Tomasin A.,University of Venice | Tomasin A.,CNR Marine Science Institute
Zeitschrift fur Geomorphologie | Year: 2011

Detailed mapping of coastline around Theologos area revealed the existence of well developed permanently submerged notches 75 ± 10 cm below present mean sea level. The regional occurrence of well preserved submerged tidal notches suggests their coseismic origin. The submergence of this Holocene shoreline possibly occurred at 1894 AD. Average submergence rate of 6.08 mm/yr may be estimated by a well preserved recumbent U-shaped notch. The retreating point depth suggests that the developing period of the notch might have been of the order of as much as three thousand years. Several non in situ large rock blocks, containing marine fossils (Lithophaga, Vermetids, Serpulids) in growth position, seem to have been projected on the coast by a tsunami wave, which might have been caused by the same coseismic episode. © 2011 Gebr. Borntraeger Verlagsbuchhandlung, Stuttgart, Germany.


Evelpidou N.,French National Center for Scientific Research | Karkani A.,National and Kapodistrian University of Athens | Pirazzoli P.A.,Laboratoire Of Geographie Physique
Holocene | Year: 2014

New geomorphological investigations along the coasts of Corfu, Othonoi, Paxoi, and Antipaxoi Islands allowed the identification of recent fossil shorelines. Former sea-level positions were deduced from sea-level indicators. A ‘modern’ tidal notch, submerged c. −20 cm, was observed in all studied islands. This notch is regarded to have been submerged by the global sea-level rise that occurred during the 19th and 20th centuries at a rate exceeding the possibilities of intertidal bioerosion. Its presence provides evidence that no vertical tectonic movements occurred since its formation. On Corfu, impacts of ancient earthquakes have left some marks of emergence at about ≥+130 ± 11, +110 ± 11, +65 ± 11, +40 ± 11, and +25 ± 11 cm, as well as marks of submergence at about −40 to −50, −85 ± 11, −120 ± 11, and −180 ± 11 cm. The emergence of +130 ± 11 cm, previously dated at about 790–400 cal. bc, was detected through erosion notches at various sites in the western part of Corfu and appears to continue even more west, at Othonoi Island. Tidal notches submerged at depths exceeding 0.4 m were observed in the northeastern part of the island and suggest the local occurrence of a sequence of four coseismic subsidences, with average vertical displacements of 40 cm, during at least the last few millennia. At Paxoi and Antipaxoi, Holocene vertical movements seem to have been mainly of subsidence. At Paxoi, the ‘modern’ notch was found at about −20 to −30 cm, while four more submerged tidal notches were distinguished at about −40 ± 11, −60 ± 11, −75 ± 11, and −90 ± 11 cm, while in Antipaxoi, three submerged tidal notches were distinguished at about −60 ± 11, −75 ± 11, and −120 ± 11 cm. © The Author(s) 2014.


Evelpidou N.,French National Center for Scientific Research | Karkani A.,National and Kapodistrian University of Athens | Kazmer M.,Eötvös Loránd University | Pirazzoli P.,Laboratoire Of Geographie Physique
Geologica Acta | Year: 2016

Fossil shorelines produced by recent co-seismic movements were identified through a submarine survey along the coasts of Ithaca and Fiscardo (Greece). In both areas a tidal notch-slightly submerged below present Mean Sea Level (MSL) was observed at various sites. This “modern” notch is known to have been submerged by the global sea-level rise during the 19th and 20th centuries. The depth after tide and air-pressure correction of the vertex of the “modern” notch (that owes its submergence to the current rapid sea level rise) was measured between -20 and -30±5cm at Fiscardo and between -36 and -45±6cm at Ithaca. This “modern” notch at the same depth on east and west sides of the Ionian Thrust suggests that both areas were not affected by the co-seismic vertical movements that occurred in 1953 (in the wider area). On the other hand, a greater depth in Ithaca could be an effect of co-seismic subsidence. Over the long term, the tectonic behavior of Ithaca differs from Fiscardo. At Ithaca no evidence of emergence was found and Holocene vertical movements have been only of subsidence: submerged fossil tidal notches were distinguished below MSL at about -40 (modern), -60, -75, -95, -106, -126, -150 and -220±6cm. On the East coast of Fiscardo peninsula impacts of ancient earthquakes have left some marks of emergence at about +18 and +44±5cm, and of submergence at about -25 (modern), -45, -60, -75, -82, -100 and -230cm, with even some evidence of past uplift and subsidence at the same sites. © 2016, Universitat de Barcelona. All rights reserved.


Evelpidou N.,National and Kapodistrian University of Athens | Koutsomichou I.,National and Kapodistrian University of Athens | Pirazzoli P.A.,Laboratoire Of Geographie Physique
Continental Shelf Research | Year: 2013

Through this research relative sea level changes from Late Holocene until the present day were studied, in the area of Skopelos and Alonnisos Islands. The study was accomplished through methodical underwater geomorphological research in both islands and led to the location of six and seven distinct submerged fossil shorelines, in Skopelos and Alonnisos accordingly, along the islands' coastline. Both islands have been affected during the last millennia, by repeated subsidence events, often of coseimic origin. The amount of each subsidence displacement was generally limited to one or a few decimetres, with recurrence intervals of some centuries. © 2013 Elsevier Ltd.


Evelpidou N.,Laboratoire Of Geographie Physique | Pirazzoli P.A.,Laboratoire Of Geographie Physique
Quaternaire | Year: 2014

Underwater geomorphological survey may reveal evidence of submerged tidal notches. In this paper, we present the methodology with the aim to reveal past temporary standstills of relative sea-level. Some examples of tidal notch development and tectonic movements are provided from fossil submerged notches mainly from Greece A vertical movement causes a displacement of the intertidal bioerosion zone. For this reason the tidal notch profile reflects changes that occurred in the relative sea-level. If the movement is rapid a new tidal notch will be formed On the contrary, if the movement is slower than the intertidal bioerosion rate, the height of the notch will increase. For this reason underwater marks on carbonate cliffs may provide evidence of recent vertical shoreline displacements of gradual or co-seismic origin.

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