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See detailUsing lacustrine sediments to record past natural hazards: The case of Fuji Five Lakes (Japan)
Lamair, Laura ULiege; Hubert, Aurelia ULiege; Yamamoto, Shinya et al

Scientific conference (2017, November 17)

In this presentation, we will focus on the Fuji Five Lakes region. Since 2013, Mt. Fuji and the Fuji Five Lakes area (Lake Motosu, Lake Shoji, Lake Sai, Lake Kawaguchi and Lake Yamanaka) are added on the ... [more ▼]

In this presentation, we will focus on the Fuji Five Lakes region. Since 2013, Mt. Fuji and the Fuji Five Lakes area (Lake Motosu, Lake Shoji, Lake Sai, Lake Kawaguchi and Lake Yamanaka) are added on the world heritage list of UNESCO. Mt. Fuji is a main touristic attraction in Japan bringing each year 300 000 tourists. The Fuji Five Lakes are located at the foot of Mt. Fuji Volcano close to the triple junction where the North American Plate, the Eurasian plate and the Philippine Sea Plate meet. Therefore, the region can be impacted by Mt. Fuji volcanic eruption as well as by large magnitude earthquakes. Additionally, nearly every year, Japan is hit by strong winds, heavy rains with flood, landslides and high waves. These natural hazards may affect the Japanese economy by causing casualties and infrastructure damage. In the regions frequently affected by natural disasters like Japan, it is crucial to have a better knowledge of the recurrence times of such disasters in order to refine the probabilistic models. For that purpose, lacustrine sediments are often used. Lacustrine sediments retrieving by coring offer several advantages compared to onland drilling: the method is cheaper, the cores are easier to take and they have longer temporal span. Lacustrine sediments are generally good archives to record past natural hazards. However, each lake has its own particular setting and a different sensitivity to record paleohazards. Coupling geophysical data, sedimentological analysis and historical records is often required to identify natural paleohazards in the sedimentary records and to define the threshold sensitivity of the lake. Here, we will used Fuji Five Lakes as natural laboratory for the recording of paleohazards (typhoons, earthquakes and volcanic eruptions) and will discuss the sedimentary record of Lake Motosu, Lake Sai, Lake Yamanaka and Lake Kawaguchi over the last ca. 6000 years regarding their geomorphological characteristics. [less ▲]

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See detailSedimentary infill at the western tip of the Gulf of Corinth during the last 120 ka: Evidence for an acceleration of the subsidence
Beckers, Arnaud; Hubert, Aurelia ULiege; Beck, Christian et al

Poster (2017, October 12)

The Corinth Rift, Greece, is a young and active continental rift stretching over 150 km between the cities of Patras and Athens, and is partly covered by the sea forming the Gulf of Corinth. The present ... [more ▼]

The Corinth Rift, Greece, is a young and active continental rift stretching over 150 km between the cities of Patras and Athens, and is partly covered by the sea forming the Gulf of Corinth. The present study is focused on the western tip of the Gulf, west of the town of Aigion, where the extension rate measured by GPS is the highest, reaching 14-16 mm/yr. The sediments were investigated using seismic reflection profiling (600 km) to characterize the evolution over the last 120 ka of the sedimentation, subsidence and faulting activity. We combined two lines of evidence, the position of lowstand deltas and isopach maps. The isopach maps were built using two stratigraphic markers could be traced through the seismic grid, the most recent one corresponds to the last post-glacial transgression and the antecedent one to MIS 6 / MIS 5 transgression, at ca. 130 ka. The related isopach maps evidence a spatial change in sedimentary infill along the rift axis probably related to a decrease in activity of the south-dipping faults (i.e. Trizonia/Mornos Faults) that formed the northern edge of the westernmost Corinth Rift in an early stage of the rifting. The different identified lowstand fluvio-deltaic deposits are related to global sea-level lowstands during which the Gulf of Corinth was a lake, whose last reconnection to the Sea occurred around 11.5 ka. Concerning lowstand deltas formed around 11.5 ka, the subsidence rates exceed 3 mm/yr and are maximal under the apex of the Mornos fan-delta (5.0-6.6 mm/yr) and in the hanging wall of the north-dipping Lambiri fault (5.9-7.5 mm/yr). Regarding the anterior lowstand delta, the subsidence was lower ranging from 1 to 2.7 mm/yr. These changes would arise because of the northward migration of the strain toward the north, e.g. the Marathias fault. [less ▲]

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See detailA 3000 yr paleoseismological history of the central East Anatolian Fault (Turkey) based on sedimentary record of Hazar Lake
Lamair, Laura ULiege; Hubert, Aurelia ULiege; Hage, Sophie et al

Poster (2017, October 10)

The East Anatolian Fault (EAF) is a major left-lateral strike-slip fault accommodating with the conjugate North Anatolian Fault the westward extrusion of the Anatolian Plate away from the Arabia-Eurasia ... [more ▼]

The East Anatolian Fault (EAF) is a major left-lateral strike-slip fault accommodating with the conjugate North Anatolian Fault the westward extrusion of the Anatolian Plate away from the Arabia-Eurasia collision zone. During the 20th century, the EAF activity was mostly quiestcent with only two events of magnitude greater than 6 recorded (1905 Malatya and the 1971 Bingol earthquakes). Historical seismicity suggests that the EAF is capable of generating earthquakes of magnitude greater than 7. In order to retrace the seismic history of the EAF in its central part, we study Hazar Lake. Hazar Lake is a 20 km long pull-apart basin with a maximum depth of 216 m. Short cores and long sediment cores were collected at four different sites to retrieve a paleoseismological record. Detailed analysis of the sediment cores (e.g. magnetic susceptibility, XRF, XRD, thin sections) were performed to identify sedimentary events. The ages of the sedimentary events were inferred based on a detailed age-depth model combining radiocarbon dating and 137Cs/210Pb. In total, 65 radiocarbon dating were done on bulk sediment and on terrestrial organic matter. The results show that Hazar Lake region was impacted by two fault zones: The East Anatolian Fault (EAF) and the North Anatolian Fault. Based on historical documents, the seismic intensity of each seismic event recorded in Hazar Lake was calculated. Here, we discuss the seismic threshold for earthquake records as well as the seismic recurrence pattern for the EAF over the last 3000 years. [less ▲]

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See detailLacustrine clay mineral assemblages as a proxy for land-use and climate changes over the last 4 kyr: The Amik Lake
El Ouahabi, Meriam ULiege; Hubert, Aurelia ULiege; Allan, Mohammed ULiege et al

Poster (2017, May 10)

Lake sediments are sensitive to landscape changes and most of these changes seem to be modulated by land-use (anthropogenic factors) coupled to palaeoenvironmental/palaeoclimatic changes. In its detrital ... [more ▼]

Lake sediments are sensitive to landscape changes and most of these changes seem to be modulated by land-use (anthropogenic factors) coupled to palaeoenvironmental/palaeoclimatic changes. In its detrital fraction, the lacustrine sediments record the history of soil erosion within its catchment via the inputs of clays and others detrital products. Within a Mediterranean context, the study investigates the upper sediments infilling the central part of the Amik basin in southern Turkey. This tectonic basin was occupied and exploited by modern human at least since 6000-7000 BC. We focus on the clay mineralogy (x-ray diffraction on oriented aggregates) and magnetic susceptibility measurements (Bartington) of the sedimentary record in the area over the last 4000 years, to assess environmental changes in relation with the different land uses and/or weathering during the successive Bronze, Iron, Roman, Islamic/Ottoman and Modern civilizations. The clay fraction of Amik Lake sediments comprises smectite, kaolinite, illite, chlorite and chlorite/smectite mixed layers that are the inherited clay phases. A relative change in abundance and crystallinity and chemistry of illite attests that environmental conditions evolved in the Amik Plain from the Bronze to Modern Age in relation with climates and/or land-use changes. The history of the Amik Lake reveals different soil erosion episode. The most intense erosion phase occurred during the Bronze/Iron Ages as indicated by the clay and magnetic susceptibility proxies. The Roman period was an exceptional period with soil erosion products arriving from the watershed, probably due the water channelization. A reduction of soil erosion occurred during the post Roman period until nowadays. Significant pedogenesis transformations are evidenced, especially during the Islamic/Ottoman periods suggesting intense chemical weathering conditions related to climate change. [less ▲]

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See detailSedimentation influx and volcanic interactions in the Fuji Five Lakes: implications for paleoseismological records
Lamair, Laura ULiege; Hubert, Aurelia ULiege; Yamamoto, Shinya et al

Conference (2017, April 27)

The Fuji Fives Lakes are located at the foot of Mount Fuji volcano close to the triple junction, where the North American Plate, the Eurasian plate and the Philippine Sea Plate meet. These lakes are ... [more ▼]

The Fuji Fives Lakes are located at the foot of Mount Fuji volcano close to the triple junction, where the North American Plate, the Eurasian plate and the Philippine Sea Plate meet. These lakes are ideally situated to study Mount Fuji volcanism and the interaction between volcanism, changes in lake sedimentation rates and the ability of lakes to record paleoearthquakes. Here, we present newly acquired geological data of Lake Yamanaka and Lake Motosu, including seismic reflection profiles, gravity and piston cores. These two lakes and their respective watersheds were affected by several eruptions of Mount Fuji. Lake Yamanaka, a very shallow lake (max. depth 14 m), was heavily impacted by the scoria fall-out of the A.D. 1707 Hoei eruption of Mount Fuji. A detailed investigation of the effect of the Hoei eruption was conducted on short gravity cores, using high resolution XRD, C/N and 210Pb/137Cs analyses. The preliminary results suggest that the sedimentation rate of Lake Yamanaka drastically reduced after the Hoei eruption, followed by an increase until the present day. Similarly, lacustrine sedimentation in Lake Motosu (max. depth 122 m) was disturbed by Mount Fuji volcanism at a larger scale. The watershed of Lake Motosu was impacted by several lava flows and scoria cones. For example, the Omuro scoria cone reduced the catchment size of Lake Motosu and modified its physiography. The related scoria fall out covered an extensive part of the lake catchment and reduced terrigenous sedimentary influx to Lake Motosu. Within the deep basin of Lake Motosu, seismic reflection data shows two different periods that are distinguished by a major change in the dominant sedimentary processes. During the first period, sublacustrine landslides and turbidity currents were the dominant sedimentation processes. During the second one, the seismic stratigraphy evidences only deposition of numerous turbidites interrupting the hemipelagic sedimentation. Changes in sedimentary processes can be linked to the modification of the lake watershed by Mount Fuji volcanism, leading to a decrease in the sediment volume that can be remobilized, and therefore disappearance of large sublacustrine landslides. Turbidites are deposited due to surficial remobilization of lake slope sediments most probably as a result of earthquake shaking. When studying sedimentological records of lakes to define the paleoearthquake record, eruptions of nearby volcanoes should be taken into account. This study suggests that a large magnitude earthquake occurring few decades after a volcanic eruption (with large scale scoria fall-out), might not be recorded in a lake, or would only be fingerprinted in the sedimentary record by small turbiditic flows. References: Miyaji N., Kan'no A., Kanamaru T., Mannen K. 2011. High-resolution reconstruction of the Hoei eruption (AD 1707) of Fuji volcano, Japan. Journal of Volcanology and Geothermal Research 207, 113–129. [less ▲]

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See detailClay minerals behaviour in thin sandy clay-rich lacustrine turbidites (Lake Hazar, Turkey)
El Ouahabi, Meriam ULiege; Hubert, Aurelia ULiege; Lamair, Laura ULiege et al

Poster (2017, April 23)

Turbidites have been extensively studied in many different areas using cores or outcrop, which represent only an integrated snapshot of a dynamic evolving flow. Laboratory experiments provide the missing ... [more ▼]

Turbidites have been extensively studied in many different areas using cores or outcrop, which represent only an integrated snapshot of a dynamic evolving flow. Laboratory experiments provide the missing relationships between the flow characteristics and their deposits. In particular, flume experiments emphasize that the presence of clay plays a key role in turbidity current dynamics. Clay fraction, in small amount, provides cohesive strength to sediment mixtures and can damp turbulence. However, the degree of flocculation is dependent on factors such as the amount and size of clay particles, the surface of clay particles, chemistry and pH conditions in which the clay particles are dispersed. The present study focuses on thin clayey sand turbidites found in Lake Hazar (Turkey) occurring in stacked thin beds. Depositional processes and sources have been previously studied and three types were deciphered, including laminar flows dominated by cohesion, transitional, and turbulence flow regimes (Hage et al., in revision). For the purpose of determine the clay behavior in the three flow regimes, clay mineralogical, geochemical measurements on the cores allow characterising the turbidites. SEM observations provide further information regarding the morphology of clay minerals and other clasts. The study is particularly relevant given the highly alkaline and saline water of the Hazar Lake. Clay minerals in Hazar Lake sediments include kaolinite (1:1-type), illite and chlorite (2:1-type). Hazar lake water is alkaline having pH around 9.3, in such alkaline environment, a cation-exchange reaction takes place. Furthermore, in saline water (16‰), salts can act as a shield and decrease the repulsive forces between clay particle surfaces. So, pH and salt content jointly impact the behaviour of clays differently. Since the Al-faces of clay structures have a negative charge in basic solutions. At high pH, all kaolinite surfaces become negative-charged, and then kaolinite particles are dispersed, and the suspension is stabilized supported by our SEM observations. In alkaline water, kaolinite reveals a lower degree of consolidation. While, alkaline water has no measurable effect on illite and chlorite surface properties due to the absence of modifications in charge. Illite and chlorite form with other clasts clusters or aggregate structures in suspension when the particle interactions are dominated by attractive energies were formed. The aggregate structure plays a major part in the flow behavior of clay suspensions. Flocs will immobilize the suspending medium, and give rise to increasing viscosity and yield strength of the suspension. [less ▲]

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See detailThe role of natural hazards and human activities on change of sedimentation patterns: The case of Lake Yamanaka (Fuji Five Lakes, Japan)
Lamair, Laura ULiege; Hubert, Aurelia ULiege; El Ouahabi, Meriam ULiege et al

Conference (2017, April 10)

The last eruption of Mt Fuji (Japan) occurred in A.D. 1707. The eruption lasted 16 days from 16 December 1707 to 1 January 1708 (Tsuya, 1955) and 1.8 km3 of volcanic materials were ejected in total ... [more ▼]

The last eruption of Mt Fuji (Japan) occurred in A.D. 1707. The eruption lasted 16 days from 16 December 1707 to 1 January 1708 (Tsuya, 1955) and 1.8 km3 of volcanic materials were ejected in total (Miyaji et al., 2011). Lake Yamanaka, a very shallow lake (max. 14. 3 m depth) located at the foot of the east-north-eastern flank of Mt Fuji, was heavily impacted by the eruption. A thick scoria layer entirely covered the catchment of Lake Yamanaka. The thickness of the deposit varies from 5 to 37 cm around Lake Yamanaka and reaches up to 149 cm at the south-west extremity of the catchment (Miyaji et al., 2011). In order to study the influence of Hoei eruption on Lake Yamanaka, 5 gravity cores were taken during the 2014 QuakeRecNankai campaign. The Hoei scoria was present at the bottom of the one core and in the core catcher of the four other cores. High resolution magnetic susceptibility, XRD, XRF, LOI, C/N and 210Pb/137Cs analyses were performed on the gravity cores. The results shows three distinct periods of sedimentation: (1) From Hoei eruption to A.D. 1900; (2) From A.D. 1900 to A.D. 1990; (3) From A.D. 1990 to A.D. 2014. The first period is characterized by a very low sedimentation rate (~0.07 cm/yr). During this period, the sediments of the catchment were trapped below the thick Hoei scoria layer. However, peaks of terrigenous input are recorded. We link such detrical signals with violent typhoons that hit the Fuji Five Lakes region. The water from the heavy rains percolated through the porous thick scoria layer and saturated it. As a result, surface runoffs carried the sediments from the catchment into Lake Yamanaka. The second period (from A.D. 1900 to A.D. 1990) is defined by an increase of the sedimentation rate (~0.16 cm/yr). The development of soil and the agriculture (e.g. pastureland, rice field, mulberry plantations) reduced the impact of Hoei scoria. The terrigenous inputs are higher than previously but remained more or less constant during this period of time. As the thickness of the scoria layer is partially reduced or covered by new soil, rains triggered by smaller typhoons could drain the sediments from watershed and transport them into the lake. The most recent period representing the last 27 years is characterized by a very high sedimentation rate (~1.036 cm/yr). The transition between period 2 and period 3 corresponds to the development of mass tourism and the urbanization around Lake Yamanaka. It is marked by an increasing of atmospheric pollution (Pb, Zn). In the upper part of the cores, a peak of 137Cs is observed. Such peak is related to cesium fall-out after Fukushima incident in 2011. In addition to the fingerprint of human impact, the lake also record a terrigenous signal related to the 2007 Fitow typhoon which provoked damage in the area. This study highlights the influence of eruptions and typhoons on the sedimentation of Lake Yamanaka. In the present day, the sedimentation recovery after a major eruption is accelerated by human activity. References: Miyaji N., Kan'no A., Kanamaru T., Mannen K. 2011. High-resolution reconstruction of the Hoei eruption (AD 1707) of Fuji volcano, Japan. Journal of Volcanology and Geothermal Research 207, 113–129. Tsuya, H. 1955. Geological and petrological studies of volcano, Fuji, V.: 5. on the 1707 eruption of Volcano Fuji. Bulletin of the Earthquake Research Institute 33, 341–383. [less ▲]

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See detailTectonic, human and climate signal over the last 4000 years in the Lake Amik record (southern Turkey)
El Ouahabi, Meriam ULiege; Hubert, Aurelia ULiege; Vander Auwera, Jacqueline ULiege et al

Poster (2017, April)

This study investigates the upper sediments infilling the central part of the Amik Basin in Southern Turkey. The Amik Basin is located in a tectonically active area: it is crossed by the Dead Sea Fault, a ... [more ▼]

This study investigates the upper sediments infilling the central part of the Amik Basin in Southern Turkey. The Amik Basin is located in a tectonically active area: it is crossed by the Dead Sea Fault, a major neotectonic structure in the Middle East extending from the Red Sea in the South to the East Anatolian Fault Zone in the North. Continuous human occupation is attested since 6000-7000 BC in the Amik Basin. The study focuses on the sedimentary record of the Lake Amik occupying the central part of the Basin. Our objective is to constrain major paleo-environmental changes over the last 4000 years. The lake has been drained and progressively dried up since the mid-50s. The absence of water column during the summer season allows to collect lacustrine samples along a 5 meter depth trench with a sampling resolution of 1 to 2 cm. Diverse complementary methods were applied to characterize the sedimentary record: i.e. magnetic susceptibility, grain size, organic and inorganic matter by loss-of-ignition, mineralogy by X-ray diffraction and core scanner X-ray fluorescence (XRF) geochemistry. The age of the record is constrained combining radionuclide and radiocarbon datings. Structural disturbances observed in the lacustrine sediments record are linked with major historical earthquakes from the 6th to the 9th century AD due to the Hasipasa Fault rupture. In addition to the tectonic influence, the sedimentary record clearly shows two periods indicating strong soil erosion in the lake catchment: (1) the most recent erosion phase occurs over the Roman period to Present; (2) the oldest one would have occurred during the Late Bronze period. Such changes are most probably related to change in land use. In term of climate influences, the mineralogical and geochemical results allow to evidence variations in chemical weathering conditions in the watershed and lake water level fluctuations, respectively. The clay mineral assemblages attest for significant pedogenesis transformations, especially during the Islamic/Ottoman period. Based on XRF results, an increase in potassium is attributed to a lake development phase during a wet phase An overflow of the Orontes River would be responsible for clay deposition. By contrast, increased calcium and strontium rather correspond to a low lacustrine level and a drier period. The Bronze and Iron/Hellenistic periods are both characterized by low lake level with limited contribution from the watershed. To conclude, our multiproxy study of the Lake Amik allows to decipher between tectonic, human and climate influences over the last 4000 years. Further step would be to compare the Amik record with other regional archives to evidence local and regional events. [less ▲]

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See detailLacustrine clay mineral assemblages as a proxy for land-use and climate changes over the last 4 kyr: The Amik Lake case study, Southern Turkey
El Ouahabi, Meriam ULiege; Hubert, Aurelia ULiege; Fagel, Nathalie ULiege

in Quaternary International (2017), 1/15

Lake sediments are sensitive to landscape changes and most of these changes seem to be modulated by land-use (anthropogenic factors) coupled to palaeoenvironmental/palaeoclimatic changes. In its detrital ... [more ▼]

Lake sediments are sensitive to landscape changes and most of these changes seem to be modulated by land-use (anthropogenic factors) coupled to palaeoenvironmental/palaeoclimatic changes. In its detrital fraction, the lacustrine sediments record the history of soil erosion within its catchment via the inputs of clays and others detrital products. Within a Mediterranean context, the study investigates the upper sediments infilling the central part of the Amik basin in southern Turkey. This tectonic basin was occupied and exploited by modern human at least since 6000-7000 BC. We focus on the clay mineralogy (x-ray diffraction on oriented aggregates) and magnetic susceptibility measurements (Bartington) of the sedimentary record in the area over the last 4000 years, to assess environmental changes in relation with the different land uses and/or weathering during the successive Bronze, Iron, Roman, Islamic/Ottoman and Modern civilizations. The clay fraction of Amik Lake sediments comprises smectite, kaolinite, illite, chlorite and chlorite/smectite mixed layers that are the inherited clay phases. A relative change in abundance and crystallinity and chemistry of illite attests that environmental conditions evolved in the Amik Plain from the Bronze to Modern Age in relation with climates and/or land-use changes. The history of the Amik Lake reveals different soil erosion episode. The most intense erosion phase occurred during the Bronze/Iron Ages as indicated by the clay and magnetic susceptibility proxies. The Roman period was an exceptional period with soil erosion products arriving from the watershed, probably due the water channelization. A reduction of soil erosion occurred during the post Roman period until nowadays. Significant pedogenesis transformations are evidenced, especially during the Islamic/Ottoman periods suggesting intense chemical weathering conditions related to climate change. [less ▲]

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See detailSoil erosion in relation to land use changes in the Amik Lake sediments near the Antioch antique city during the last 4kyr
El Ouahabi, Meriam ULiege; Hubert, Aurelia ULiege; Lebeau, Héléne et al

in The Holocene (2017)

The Amik Basin in the Eastern Mediterranean region occupied since 6000-7000 BC has sustained a highly variable anthropic pressure culminating during the Late Roman Period when the Antioch city reached its ... [more ▼]

The Amik Basin in the Eastern Mediterranean region occupied since 6000-7000 BC has sustained a highly variable anthropic pressure culminating during the Late Roman Period when the Antioch city reached its golden age. The present 6m long sedimentary record of the Amik Lake occupying the central part of the Basin constrains major paleo-environmental changes over the last 4000 years using a multi-proxy analyses (grain-size, magnetic susceptibility and XRF geochemistry). An age model is provided by combining short-lived radionuclides with radiocarbon dating. A lake/marsh prevailed during the last 4kyrs with a level increase at the beginning of the Roman Period possibly related to optimum climatic condition and water channelling. The Bronze/Iron Ages are characterized by a strong terrigenous input linked to deforestation, exploitation of mineral resources and the beginning of upland cultivation. The Bronze/Iron Age transition marked by the collapse of the Hittite Empire is clearly documented. Erosion continues during the Roman Period and nearly stopped during the Early Islamic Period in conjunction with a decreasing population and soil depletion on the calcareous highland. The soil-stripped limestone outcrops triggered an increase in CaO in the lake water, and a general decrease in ZrO2 released in the landscape that lasts until the present day. During the Islamic Period, pastoralism on the highland sustained continued soil erosion of the ophiolitic Amanus Mountains. The modern Period is characterized by a higher pressure particularly on the Amanus Mountains linked to deforestation, road construction, ore exploitation and the drying of the lake for agriculture practices. [less ▲]

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See detailEarthquake imprints on a lacustrine deltaic system: Example of the Kürk Delta along the East Anatolian Fault (Turkey)
Hubert, Aurelia ULiege; El Ouahabi, Meriam ULiege; Moreno, David et al

in Geophysical Research Abstracts (2017), 19

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See detailGeochemistry and mineralogy approaches to characterize brick and its lake sediments sources: Antioch Roman City (Southern Turkey)
El Ouahabi, Meriam ULiege; Hubert, Aurelia ULiege; Benjelloun, Yacine et al

Poster (2016, July)

The Roman aqueduct of Antioch-on-the-Orontes (Southern Turkey) is situated close to the Antioch city. This last is located near the Amik Lake (Lake of Antioch) and close to the junction between the active ... [more ▼]

The Roman aqueduct of Antioch-on-the-Orontes (Southern Turkey) is situated close to the Antioch city. This last is located near the Amik Lake (Lake of Antioch) and close to the junction between the active Dead Sea fault and the East Anatolian fault. During the Roman period, the Amik Plain was more densely occupied than at any time in its history [1]. The study focuses on the bricks and the lake sediments characterization in order to determine the source area as well as the technical production used at this period. For this purpose, several bricks were sampled on different parts of the city's aqueducts. Furthermore, a core of about 6 m of sediments was also collected from the dried Amik Lake. The bricks were characterized through a mineralogical (XRD) and chemical (PIXE-PIGE) approaches. Unfired clay fraction remained as inclusion in the brick was separated and then analysed using XRD. Geochemical composition and clay mineralogy were performed on the raw sediments from the Amik Lake in order to compare the source area. Technological test will be performed on the raw clay sediments from the Amik Lake in the purpose to understand the production techniques used at this time. The age of the brick production was previously dated to the Roman Period [2]. The synthesis of all the data attested the Amik Lake sediment as the raw material for the bricks of the aqueduct. Clay mineral composition from the Roman period deposited in the lake is smectite, illite, kaolinite and small amount of mixed-layer clays. The similar clays composition is found in the remained clays on the brick used for the aqueduct construction. Fast and heterogeneous firing practice characterized the manufacturing of these materials due to the rapid need for the materials during the post-seismic repairs after earthquakes that are mentioned in historical written works. [1] J. Casana, Geomorphology, 101, 429-442 (2008) [2] Y. Benjelloun, J. de Sigoyer, J. Carlut, A. Hubert-Ferrari, H. Dessales, H. Pamir, V. Karabacak, Comptes Rendus Geoscience, 347, 170-180 (2015) [less ▲]

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See detailPaleoenvironmental implications in the dried lake sediments (Amik Lake, Southern Turkey)
El Ouahabi, Meriam ULiege; Hubert, Aurelia ULiege; Vander Auwera, Jacqueline ULiege et al

Poster (2016, July)

The Amik Basin in the Eastern Mediterranean region has been continuously inhabited since 6000 – 7000 BC. The study focuses on the sedimentary record of the Amik Lake located in the central part of the ... [more ▼]

The Amik Basin in the Eastern Mediterranean region has been continuously inhabited since 6000 – 7000 BC. The study focuses on the sedimentary record of the Amik Lake located in the central part of the basin. Our objective is to constrain major paleo-environmental changes in the area over the last 4000 years and to unravel possible human impacts on the sedimentation. A diverse array of complementary methods was applied on the 6 m long record. Mineralogical (XRD), and geochemical (XRF) analyses were performed. The age of the record is constrained combining radionuclide and radiocarbon dating. A high sedimentation rate of 0.12 cm/yr was inferred at the studied site. The 4000 years (since ~1800 BC) long record shows that significant fluctuations of the lake level and the riverine system inflow into the Amik Lake occurred. The Late Bronze lowstand led to punctual dryings of the lake at the end of the Bronze/Iron Age transition. At that time, the rivers yielded a large terrigenous input linked to strong soil erosion related mainly to deforestation and exploitation of mineral resources. During the Roman and later periods, upland soils were partly depleted and the riverine system completely transformed by channelization (anthropic) that led to a marshification of the Amik Basin [1]. Chemical and mineralogical composition of sediments is quite diversified reflecting the significant geological variation of drainage basins. Periods with strong aggradation linked to major increase in erosion were identified and characterized by high amount of Cr, Ni and Zr. Levels relatively rich in fluorite, richterite, enstatite, hornblende and chrysotile are a result of the erosion of the ophiolitic rocks from the surrounding Amanos Mountains. These levels are interpreted as periods of relatively high physical erosion, while more humid periods led to more intensive weathering. Consequently, the dominance of kaolinite, muscovite/illite and talc indicates a climate with contrasting seasons. During the most recent period a marked increase in terrigenous minerals associated with a rise in dolomite indicates ungoing erosion as well as the drying-out of the lake. [1] T.J. Wilkinson, L. Rayne, Water History, 2, 115-144 (2010). [less ▲]

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See detailChemical and mineralogical proxies of erosion episodes in the dried lake sediments (Amik Lake, Southern Turkey): paleoenvironmental implications
El Ouahabi, Meriam ULiege; Hubert, Aurelia ULiege; Lebeau, Héléne et al

Poster (2016, April 17)

The Amik Basin in the Eastern Mediterranean region has been continuously occupied since 6000-7000 BC. The landscape has sustained with highly variable anthropic pressure culminating during the Late Roman ... [more ▼]

The Amik Basin in the Eastern Mediterranean region has been continuously occupied since 6000-7000 BC. The landscape has sustained with highly variable anthropic pressure culminating during the Late Roman Period when the Antioch city reached its golden age. The basin also sustained a high seismic activity (M≥7) as it is a releasing step-over along the Dead Sea Fault. The study focuses on the sedimentary record of the Amik Lake occupying the central part of the Basin. Our objective is to constrain major paleo-environmental changes in the area over the last 4000 years and to unravel possible human impacts on the sedimentation. A diverse array of complementary methods was applied on the 6 m long record. High resolution of mineralogical (XRD) and geochemical (XRF) analyses were performed. Quantitative mineralogical phases of sediments by the Rietveld method were computed using Topaz software. The age of the record is constrained combining radionuclide and radiocarbon dating, and checked using the correlation between the earthquake history and rapidly deposited layer identified. A high sedimentation rate of 0.12 cm/yr was inferred at the coring site. The 4000 years old record shows that significant fluctuations of the lake level and the riverine system inflow into the Amik Lake occurred. The Late Bronze lowstand leaded to punctual dryings of the lake at the end of the Bronze/Iron transition marked by the collapse of the Hittite Empire and during the Dark ages. At that time, the riverine was carrying a large terrigenous input linked to strong soil erosion related to deforestation, exploitation of mineral resources and the beginning of upland cultivation. During the Roman Period and in the later periods, upland soils were partly depleted and the riverine system completely transformed by channelization that leaded to a mashification of the Amik Basin. Chemical and mineralogical composition of sediments is quite diversified reflecting the significant geological variation of drainage basins. Abundant calcareous minerals, especially calcite, aragonite, dolomite and small amount of wollastonite characterize the different sedimentary levels recorded in the lake. Levels relatively rich in fluorite, richerite, enstatite, and wollastonite are a result of the erosion of the ophiolitic rocks from the surrounding Amanos Mountains. These levels are interpreted as corresponding to relatively high erosive periods, while more humid periods lead to more intensive weathering and consequently to the dominance of kaolinite, muscovite/illite and talc more advanced in the relative stability scale, indicating a climate with contrasting seasons. During the most recent Period a marked increase in terrigeneous minerals associated with a rise in dolomite indicates ungoing erosion as well as the drying-out of the lake. [less ▲]

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See detailA history of mass transport complexes related to eruptions and earthquake shaking: the case of Lake Motosu (Japan).
Lamair, Laura ULiege; Hubert, Aurelia ULiege; El Ouahabi, Meriam ULiege et al

Conference (2016, March 04)

The QuakeRecNankai project focuses on geological records of paleoearthquakes along the Nankai-Suruga subduction zone, south central Japan. In the framework of the project, we investigated the Fuji Five ... [more ▼]

The QuakeRecNankai project focuses on geological records of paleoearthquakes along the Nankai-Suruga subduction zone, south central Japan. In the framework of the project, we investigated the Fuji Five Lakes, located at the eastern end of the Nankai-Suruga Trough. Here, we present results from Lake Motosu, the deepest of the Fuji Five Lakes (max. depth 122 m), including seismic reflection profiles, gravity cores and preliminary results of 6.8 m long piston core. We identify mass transport deposits and turbidites possibly triggered by earthquakes. We study the lake sedimentary architecture and the Holocene sedimentation with a high resolution GEOPULSE pinger system. A seismic grid with total length of 39 km covered the lake. We identify a specific seismic horizon that may be related to the Aokigaraharamarubi lava flow (864 A.D.). Strong reflectors may also correlate with tephra layers from Oniwa-Okuniwa eruptions (620-790 A.D). In the western part of the lake, the seismic reflection profile reveals a change after the proposed Oniwa-Okuniwa eruptions in terms of volume and length of mass transport deposits. Large mass-transport deposits occurring before the eruptions are characterized by chaotic seismic facies. After the eruptions, the mass-transport deposits are much smaller and are characterized by transparent seismic facies attributed to turbiditic flow. Six gravity cores (max. 90cm long) provide samples of the lake bottom sediments. In these cores, turbidites and megaturbidites were identified based on facies analyses, combined with X-ray scanning, geophysical properties, grain-size analysis, mineralogy and XRF. During the period between the Oniwa-Okuniwa eruptions and the Aokigaraharamarubi lava flow (620-864 A.D), several lava flows occurred in the northern part of Mount Fuji and drastically modified the catchment of Lake Motosu. The decreasing of the size of catchment led to a decreasing of sedimentary yield in the lake. The change in the sedimentation rate could partly explain why we have a change in the type of mass transport deposit. Additionally, analyses were performed to define the minimum shaking intensity required to destabilize the slope. To assess slope stability, we investigated the clay content and the clay mineralogy of samples taken along the slope. In this presentation, we discuss the link between eruptions of Mount Fuji, decreasing of the size of the catchment, sedimentation rate and earthquake shaking. [less ▲]

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See detailA history of mass transport complexes related to earthquake shaking: the case of Lake Motosu (Japan).
Lamair, Laura ULiege; Hubert, Aurelia ULiege; Boes, Evelien et al

Poster (2016, January 27)

The QuakeRecNankai project focuses on geological records of paleoearthquakes along the Nankai-Suruga subduction zone, south central Japan. In the framework of the project, we investigated the Fuji Five ... [more ▼]

The QuakeRecNankai project focuses on geological records of paleoearthquakes along the Nankai-Suruga subduction zone, south central Japan. In the framework of the project, we investigated the Fuji Five Lakes, located at the eastern end of the Nankai-Suruga Trough. Here, we present results from Lake Motosu, the deepest of the Fuji Five Lakes (max. depth 122 m), including seismic reflection profiles and gravity cores. We identify mass transport deposits and turbidites possibly triggered by earthquakes. We study the lake sedimentary architecture and the Holocene sedimentation with a very high resolution GEOPULSE pinger system. A seismic grid with total length of 39 km covered the lake. We identify a specific seismic horizon that may be related to the Aokigaraharamarubi lava flow (864 A.D.). Strong reflectors may also correlate with tephra layers from Oniwa-Okuniwa eruptions (620-790 A.D). In the western part of the lake, the seismic reflection profile reveals a change after the proposed Oniwa-Okuniwa eruptions in terms of volume and length of mass transport deposits. Large mass-transport deposits occurring before the eruptions are characterized by chaotic seismic facies. After the eruptions, the mass-transport deposits are much smaller than previously and characterized by transparent seismic facies attributed to a turbiditic flow. Six gravity cores (max. 90cm) provide samples of the lake bottom sediments. In these cores, turbidites were identified based on facies analyses, combined with X-ray scanning, geophysical properties, grain-size analysis, mineralogy and XRF. An age-depth model was established based on radionuclide dating. We compare the timing of sedimentary events in Lake Motosu with a historical catalogue of natural hazards in the Fuji Five Lakes area, including historical records of megathrust earthquakes rupturing the Nankai subduction zone, the Sagami Trough and other earthquakes occurring along inland faults. Several analyses were performed to understand why we have a change in type of mass transport deposit after the eruptions and to define the minimum shaking intensity required to destabilize the slope. To assess slope stability, we investigated the clay content and the clay mineralogy of the slope. Spatial statistics was also performed in order to evaluate the degree of the slope and the accumulation of sediment. We suggest that the presence of a scoria layer might have contributed to slope destabilization. [less ▲]

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Full Text
See detailThe Fuji Five Lakes, a dynamic environment that has sustained large changes linked to volcanic eruptions, earthquakes and landslides: New evidences from the lake survey
Hubert, Aurelia ULiege

Conference (2016, January 22)

Within the framework of the QuakeRecNankai project, about 122 km of seismic reflection profiles were acquired in Lakes Motosu, Sai, Kawaguchi and Yamanaka, and short gravity cores and long piston cores ... [more ▼]

Within the framework of the QuakeRecNankai project, about 122 km of seismic reflection profiles were acquired in Lakes Motosu, Sai, Kawaguchi and Yamanaka, and short gravity cores and long piston cores were collected. The talk based on the newly acquired data will explain that the Fuji Five Lakes do not only record past activity of the Fuji Volcano. Large earthquakes are likely to have impacted the lakes, because strong earthquake shaking has the potential to weaken rocks and soils, which results in mass movement and in sediment remobilization. Large mass transport deposits were documented in all the Fuji Five Lakes. In Lake Yamanaka, a min. 5 000 000 m3 mass flow took place along its southern shore extending to the lake center ~ 2600-2100 yrs ago. In Lake Kawaguchi, smaller mass transport deposits occurred after Higashiken lava flows (~3800-4000 yrs ago). Lake Motosu shows the most extensive record with numerous landslides occurring before ~ 3000 yrs BP. The largest mass transport deposit covers an area of 0.89 km2 and its upper part was sampled by a piston core. Seismic shaking can also remobilized sediments previously deposited leading to turbiditic flows that settled into the deep depocenter of the lakes. This process was evidenced in Lakes Motosu and Kawaguchi [less ▲]

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Peer Reviewed
See detailInfluence of bottom currents on the sedimentary processes at the western tip of the Gulf of Corinth, Greece
Beckers, Arnaud ULiege; Beck, Christian; Hubert, Aurelia ULiege et al

in Marine Geology (2016)

We investigated the sedimentary processes that were active during the Holocene in the Gulf of Corinth, using high-resolution seismic reflection profiles and gravity cores. Seismic reflection data clearly ... [more ▼]

We investigated the sedimentary processes that were active during the Holocene in the Gulf of Corinth, using high-resolution seismic reflection profiles and gravity cores. Seismic reflection data clearly show the presence of shallow-water sediment drifts at the western end of the Gulf, close to the Rion Sill that links the gulf to the Ionian Sea. Short cores indicate that drifts are composed of homogenous bioturbated mud in their upper part. The drift deposits flank a wide central area where the sea floor is eroded and where pre-Holocene deposits locally outcrop. The sea floor morphology in this area is marked by furrows oriented in different directions and by a depression attributed to the action of bottom-currents. The magnetic fabric of sediment samples from the drift, shelves, sub-basins and from the basin floor show a significant anisotropy and a similar orientation of Kmax axes along core. The largest anisotropy (P = 1.043 ± 0.007) is observed in the drift and is interpreted as resulting from the action of bottom currents. The similar orientation of Kmax axes in the other cores, collected from areas East of the drifts, suggests that bottom currents also affect sediment deposition in the rest of the study area, even if seismic profiles and core analyses demonstrate that gravitational processes such as submarine landslides and turbidity currents exert the main control on sediment transport and deposition. Average Kmax axes for four cores were reoriented using the declination of the characteristic remanent magnetization. Kmax axes show variable orientations relatively to the slope of the sea floor, between along-slope and roughly parallel to the contour lines. [less ▲]

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Peer Reviewed
See detailSedimentary impacts of recent moderate earthquakes from the shelves to the basin floor in the western Gulf of Corinth
Beckers, Arnaud; Beck, Christian; Hubert, Aurelia ULiege et al

in Marine Geology (2016)

In seismically active areas, long term records of large earthquakes are indispensable to constrain reccurence patterns of large earthquakes. In the western Corinth Rift, one of the most active areas in ... [more ▼]

In seismically active areas, long term records of large earthquakes are indispensable to constrain reccurence patterns of large earthquakes. In the western Corinth Rift, one of the most active areas in Europe in terms of seismicity, data about ancient earthquakes are still insufficient, despite historical records covering the last two millenia and several studies in onshore paleoseimology. In this paper, we test the use of offshore sediments from the Gulf of Corinth to identify sediment failures and tsunamis that have been triggered by historical earthquakes. Two shelves (40-100 m deep), one sub-basin (180 m) and the basin floor (330 m) have been sampled by short gravity cores. The cores were analysed in order to identify and characterize event deposits. The age control has been provided by 137Cs and 210Pb activity measurements showing that the cores represent 2 to 4 centuries of sedimentation. In each site, sandy event deposits are interbeded in the muddy, hemipelagic sedimentation. The age of event deposits has been compared to the record of historical earthquakes using new and published macroseismic data. This comparison shows temporal coincidence of some event deposits and documented earthquakes with a macroseismic intensity ≥ VII in the area, e.g. in A.D. 1861, 1888 and 1909. In near-shore, shallow water settings, the record of event deposits does not exactly fit with the historical record of large earthquakes because too few event deposits are present. This may be due to the absence of sediment failures or to a lower preservation of the deposits in such settings. In the deepest site, in the basin floor, the correspondence is better: a sandy turbidite probably corresponds to each large earthquake since A.D. 1850, except one aseismic sediment density flow that occurred at the end of the 20th century. Surprisingly, the Ms=6.2, June 15, 1995 Aigion earthquake is only possibly recorded in one near-shore site on the Aigion Shelf, in the form of a tsunami back-wash flow deposit. This study showed that moderate earthquakes (M 5.8-6.5) can significantly impact marine sediments. Regarding the evaluation of seismic hazard in the area, the basin floor is proposed as a promising site for long term paleoseismology in the Gulf of Corinth, while shallower settings need to be considered more carefully [less ▲]

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