scholarly journals The active tectonic landscape of Lake Ohrid (FYR of Macedonia/Albania)

2014 ◽  
Vol 56 (6) ◽  
Author(s):  
Nadine Hoffmann
Keyword(s):  
Active Faults ◽  
Fault Scarp ◽  
Mass Wasting ◽  
Lake Ohrid ◽  
Slip Rates ◽  
Active Tectonic ◽  
Western Border ◽  
Wine Glass ◽  
Yugoslavian Republic ◽  
Fault Scarps

<p><span style="font-family: CMR10; font-size: medium;">The study area at the Lake Ohrid Basin is located on 693 m a.s.l. at the south-western border of the Former Yugoslavian Republic of Macedonia with Albania. It is a suitable location for neotectonic studies. It exhibits a large variety of morphological expressions associated with the seismic activity of the region. Linear bedrock fault scarps give the relief on both sides of the lake a staircase-like appearance; other features are wine-glass shaped valleys and triangular facets. These often short living features are used to identify active faults and to parameterise palaeoearthquakes (slip rates, subsidence and erosion). According to the results of fault scarp profiling a halfgraben shape of the basin is proposed with the west coast being dominated by mass wasting processes most likely triggered by seismic events.</span></p>

Internal structure, active tectonics and dynamic topography of the eastern Nankai accretionary prism toe, Japan, and its tsunamigenic potential

2018 ◽  
Vol 158 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Kiichiro Kawamura ◽  
Yujiro Ogawa
Keyword(s):  
Active Faults ◽  
Active Tectonics ◽  
Accretionary Prism ◽  
Fault Scarp ◽  
Burial Depth ◽  
Dynamic Topography ◽  
Slip Rates ◽  
Uplift Rates ◽  
Thrust Zone ◽  
Nankai Earthquake

AbstractThe eastern Nankai accretionary prism toe was surveyed to evaluate the nature and deformation of its frontal thrust. According to the determined porosities and yield strengths, turbidites were successively buried down to depths of 250–300 m before accretion, and were then exposed at the prism toe by uplift along the Tenryu frontal thrust during 3.4–1.98 Ma. Consolidation tests provided reasonable estimates of burial depth and, when combined with exposed sediment dates, yield prism toe uplift rates of 0.74–2.27 m ka–1. The displacement along the frontal thrust is estimated to be 500–900 m and the slip rates are 1.47–4.55 m ka–1, corresponding to the highest class of active faults on land in Japan. During the surveys of the Tenryu frontal thrust zone, we discovered a new active fault scarp that was several tens of centimetres high, interpreted to be a protothrust located c. 100 m south of the frontal thrust. This scarp is associated with chemosynthetic biocommunities. The thrust might potentially be the result of displacement during the East Nankai (To-Nankai) earthquake (Mw 8.1) in 1944. These lines of evidence indicate that the Tenryu frontal thrust is still active and that displacement along the thrust might induce a tsunami during future Tokai or To-Nankai earthquakes.

Connecting seismicity, gravity-driven erosion and deposition at submarine normal faults: Insights from mapping of the 2004 Mw 6.3 Les Saintes earthquake rupture (French Antilles)

2020 ◽  
Author(s):  
Javier Escartin ◽  
Jeremy Billant ◽  
Frédérique Leclerc ◽  
Jean-Arthur Olive ◽  
Klemen Istenic ◽  
...  
Keyword(s):  
Hanging Wall ◽  
Fault Scarp ◽  
Coseismic Deformation ◽  
Seismic Events ◽  
Fault Rupture ◽  
Mass Wasting ◽  
Erosion And Deposition ◽  
Gravity Driven ◽  
Les Saintes ◽  
Fault Scarps

&lt;p&gt;During the ODEMAR 2013 and SUBSAINTES 2017 cruises we mapped the full extent of the seafloor rupture associated with the 2004 Mw 6.3 Les Saintes extensional earthquake. Near-bottom bathymetry acquired both with ROVs and AUVs along the Roseau Fault reveal a normal fault scarp developing in an extensional graben within the Caribbean volcanic arc, between the islands of Guadeloupe and Dominica. Optical inspection during ROV dives along the scarp&amp;#8217;s base, where fault mirrors are well-preserved, allowed us to identify and characterize the coseismic fault rupture, and measure the coseismic displacements using both laser calipers and measurements performed on video-derived, textured 3D models, with accuracies better than 1 cm.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;The 2004 rupture extends ~20 km along the Roseau Fault, with a vertical displacement exceeding 2.5 m at its center, and tapering towards its ends. Local variations in apparent fault slip within a single 3D model (fault lengths of ~10 to 300 m) document local deposition of gravity debris cones at the base of the scarp, extending laterally between a few to tens of m, and covering the coseismic markers. Gullies eroding the footwall and depositing debris cones on the hanging wall do not show any significant displacement. Fault scarps on either side of the gully mouth instead record significant displacements, suggesting that either erosion or deposition along the gully bottom efficiently obliterated markers of coseismic deformation.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;We inspected all overlapping seafloor imagery acquired in December 2013 and April 2017, &gt;10 years after the 2004 Les Saintes earthquake, extending laterally over &gt;3 km of the Roseau Fault rupture. &amp;#160;Neither the bed of gullies crossing the rupture, nor the debris and rubble at the base of the fault scarp show any noticeable seafloor change indicating mass wasting and transport, and only changes in mobile sediment (e.g., ripples) can be detected between both image sets. &amp;#160;We identified a single area, ~2m wide, with apparent deposition of pebbles during these 3.25 years period, and associated with a local mass-wasting event.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;These observations point towards a systematic triggering of mass-wasting during seismic events, with deposition of rubble and rocks both at dejection cones at the mouth of gullies, or at the base of fault scarp sections displaying fault mirrors, covering or obliterating the coseismic markers. Therefore, long-term erosion and deposition processes here are gravity-driven and triggered by the history and magnitude of seismic events. Similar seismic controls may enable denudation of exposed oceanic lithosphere at fault scarps developing along and flanking mid-ocean ridges.&lt;/p&gt;

Slip rates along active faults estimated with cosmic-ray–exposure dates: Application to the Bogd fault, Gobi-Altaï, Mongolia

Geology ◽  
1995 ◽  
Vol 23 (11) ◽  
pp. 1019 ◽  
Author(s):  
J. F. Ritz ◽  
E. T. Brown ◽  
D. L. Bourlès ◽  
H. Philip ◽  
A. Schlupp ◽  
...  
Keyword(s):  
Active Faults ◽  
Cosmic Ray ◽  
Slip Rates

scholarly journals Active Fault Systems in the Inner Northwest Apennines, Italy: A Reappraisal One Century after the 1920 Mw ~6.5 Fivizzano Earthquake

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 139
Author(s):  
Giancarlo Molli ◽  
Isabelle Manighetti ◽  
Rick Bennett ◽  
Jacques Malavieille ◽  
Enrico Serpelloni ◽  
...  
Keyword(s):  
Large Scale ◽  
Active Fault ◽  
Active Faults ◽  
Dense Network ◽  
Earthquake Fault ◽  
Slip Rates ◽  
Fault Systems ◽  
Seismological Data ◽  
Seismogenic Faults

Based on the review of the available stratigraphic, tectonic, morphological, geodetic, and seismological data, along with new structural observations, we present a reappraisal of the potential seismogenic faults and fault systems in the inner northwest Apennines, Italy, which was the site, one century ago, of the devastating Mw ~6.5, 1920 Fivizzano earthquake. Our updated fault catalog provides the fault locations, as well as the description of their architecture, large-scale segmentation, cumulative displacements, evidence for recent to present activity, and long-term slip rates. Our work documents that a dense network of active faults, and thus potential earthquake fault sources, exists in the region. We discuss the seismogenic potential of these faults, and propose a general tectonic scenario that might account for their development.

Epicentral intensities and damage in the Hebgen Lake, Montana, earthquake of August 17, 1959

1962 ◽  
Vol 52 (2) ◽  
pp. 181-234
Author(s):  
Karl V. Steinbrugge ◽  
William K. Cloud
Keyword(s):  
Ground Motions ◽  
Strong Motion ◽  
Fault Scarp ◽  
Rock Falls ◽  
Small Unit ◽  
The Earth ◽  
Major Fault ◽  
Seismograph Station ◽  
Fault Scarps ◽  
Earth Fill

ABSTRACT An extensive fault scarp system was formed during the Hebgen Lake earthquake of August 17, 1959 (11:37:15 p.m., M.S.T., Gutenberg-Richter magnitude 7.1). Bedrock beneath Hebgen Lake warped, rotated, and caused a seiche in the lake. A major landslide dammed Madison Canyon, causing a lake to form above the slide. An estimated 19 persons were buried by the slide. Other slides and rock falls took out sections of the main highway north of Hebgen Lake and closed many roads in Yellowstone Park. Small unit masonry structures as well as wooden buildings along the major fault scarps usually survived with little damage when subjected only to vibratory forces. The unit masonry buildings, in particular, had little or no earthquake bracing. Intensity at the major scarp has been given a Modified Mercalli Scale rating of X. However, the maximum intensity ratings based on vibratory motion even a few feet away from the scarps were VII or VIII. Within the limits of observation there was little or no reduction in vibratory intensity 5 to 10 miles away compared to that at the fault. This is not to say that the ground motions were similar. At the closest strong-motion seismograph station (Bozeman, 58 miles from the epicenter) maximum recorded acceleration was about 7 per cent gravity. The earthquake was generally felt in about a 600,000 square mile area, mostly north of the instrumental epicenter. The earth-fill Hebgen Dam was within 1000 feet of a major scarp. The dam was significantly damaged, but it continued to be an effective structure.

scholarly journals Seismic Activity of the Manisa Fault Zone in Western Turkey Constrained by Cosmogenic 36Cl Dating

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 451
Author(s):  
Nasim Mozafari ◽  
Çağlar Özkaymak ◽  
Dmitry Tikhomirov ◽  
Susan Ivy-Ochs ◽  
Vasily Alfimov ◽  
...  
Keyword(s):  
Fault Zone ◽  
Normal Fault ◽  
Vertical Displacement ◽  
Historical Records ◽  
Western Turkey ◽  
Slip Rates ◽  
Vertical Displacements ◽  
Surface Ruptures ◽  
Fault Scarps ◽  
Calculated Average

This study reports on the cosmogenic 36Cl dating of two normal fault scarps in western Turkey, that of the Manastır and Mugırtepe faults, beyond existing historical records. These faults are elements of the western Manisa Fault Zone (MFZ) in the seismically active Gediz Graben. Our modeling revealed that the Manastır fault underwent at least two surface ruptures at 3.5 ± 0.9 ka and 2.0 ± 0.5 ka, with vertical displacements of 3.3 ± 0.5 m and 3.6 ± 0.5 m, respectively. An event at 6.5 ± 1.6 ka with a vertical displacement of 2.7 ± 0.4 m was reconstructed on the Mugırtepe fault. We attribute these earthquakes to the recurring MFZ ruptures, when also the investigated faults slipped. We calculated average slip rates of 1.9 and 0.3 mm yr−1 for the Manastır and Mugırtepe faults, respectively.

scholarly journals Tectonic Geomorphology and Paleoseismology of the Sharkhai fault: a new source of seismic hazard for Ulaanbaatar (Mongolia)

2021 ◽  
Author(s):  
Abeer Al-Ashkar ◽  
Antoine Schlupp ◽  
Matthieu Ferry ◽  
Ulziibat Munkhuu
Keyword(s):  
Seismic Hazard ◽  
Scaling Laws ◽  
Active Faults ◽  
Seismic Hazard Assessment ◽  
Capital City ◽  
Tectonic Geomorphology ◽  
Time Interval ◽  
Coseismic Slip ◽  
Slip Rates ◽  
Large Earthquakes

Abstract. We present new constraints from tectonic geomorphology and paleoseismology along the newly discovered Sharkhai fault near the capital city of Mongolia. Detailed observations from high resolution Pleiades satellite images and field investigations allowed us to map the fault in detail, describe its geometry and segmentation, characterize its kinematics, and document its recent activity and seismic behavior (cumulative displacements and paleoseismicity). The Sharkhai fault displays a surface length of ~40 km with a slightly arcuate geometry, and a strike ranging from N42° E to N72° E. It affects numerous drainages that show left-lateral cumulative displacements reaching 57 m. Paleoseismic investigations document the faulting and deposition record for the last ~3000 yr and reveal that the penultimate earthquake (PE) occurred between 1515 ± 90 BC and 945 ± 110 BC and the most recent event (MRE) occurred after 860 ± 85 AD. The resulting time interval of 2080 ± 470 years is the first constraint on the Sharkhai fault for large earthquakes. On the basis of our mapping of the surface rupture and the resulting segmentation analysis, we propose two possible scenarios for large earthquakes with likely magnitudes between 6.4 ± 0.2 and 7.1 ± 0.2. Furthermore, we apply scaling laws to infer coseismic slip values and derive preliminary estimates of long-term slip rates between 0.2 ± 0.2 and 1.0 ± 0.5 mm/y. Finally, we propose that these original observations and results from a newly discovered fault should be taken into account for the seismic hazard assessment for the city of Ulaanbaatar and help build a comprehensive model of active faults in that region.

scholarly journals Paleoearthquake history of the Spili fault

2017 ◽  
Vol 47 (2) ◽  
pp. 595
Author(s):  
V. Mouslopoulou ◽  
D. Moraetis ◽  
L. Benedetti ◽  
V. Guillou ◽  
D. Hristopulos
Keyword(s):  
Rare Earth ◽  
Active Faults ◽  
Fault Scarp ◽  
Large Magnitude ◽  
Earthquake Recurrence ◽  
Earthquake Parameters ◽  
History Of ◽  
Earthquake Recurrence Interval ◽  
Seismic Displacements

The paleoearthquake activity on the Spili Fault is examined using a novel methodology that combines measurements of Rare Earth Elements (REE) and of in situ cosmogenic 36Cl on the exhumed fault scarp. Data show that the Spili Fault is active and has generated a minimum of five large-magnitude earthquakes over the last ~16500 years. The timing and, to a lesser degree, the slip-size of the identified paleoearthquakes was highly variable. Specifically, the two most recent events occurred between 100 and 900 years BP producing a cumulative displacement of 3.5 meters. The timing of the three older paleoearthquakes is constraint at 7300, 16300 and 16500 years BP with slip sizes of 2.5, 1.2 and 1.8 meters, respectively. The magnitude of the earthquakes that produced the measured co-seismic displacements, ranges from M 6.3-7.3 while the average earthquake recurrence interval on the Spili Fault is about 4200 years. The above data suggest that the Spili is among the most active faults on Crete and its earthquake parameters may be incorporated into the National Seismic Hazard Model.

Paleoearthquakes on the Húsavík-Flatey Fault in northern Iceland: Where are the large earthquakes?

2021 ◽  
Author(s):  
Remi Matrau ◽  
Yann Klinger ◽  
Jonathan Harrington ◽  
Ulas Avsar ◽  
Esther R. Gudmundsdottir ◽  
...  
Keyword(s):  
Slip Rate ◽  
Late Glacial ◽  
Fault Scarp ◽  
Alluvial Fan ◽  
Tectonic Deformation ◽  
Birch Wood ◽  
Alluvial Deposits ◽  
Slip Rates ◽  
Tephra Layers ◽  
Large Earthquakes

&lt;p&gt;Paleoseismology is key to study earthquake recurrence and fault slip rates during the Late Pleistocene-Holocene. The H&amp;#250;sav&amp;#237;k-Flatey Fault (HFF) in northern Iceland is a 100 km-long right-lateral transform fault connecting the onshore Northern Volcanic Zone to the offshore Kolbeinsey Ridge and accommodating, together with the Gr&amp;#237;msey Oblique Rift (GOR), ~18 mm/yr of relative motion between the Eurasian and North American plates. Significant earthquakes occurred on the HFF in 1755, 1838 and 1872 with estimated magnitudes of 6.5-7. However, historical information on past earthquakes prior to 1755 is very limited in both timing and size.&lt;/p&gt;&lt;p&gt;We excavated five trenches in a small basin (Vestari Krubbssk&amp;#225;l) located 5.5 km southeast of the town of H&amp;#250;sav&amp;#237;k and at 300 m.a.s.l. and one trench in an alluvial fan (Tra&amp;#240;arger&amp;#240;i) located 0.5 km north of H&amp;#250;sav&amp;#237;k and at 50 m.a.s.l. In a cold and wet environment, such as in coastal parts of Iceland, one has to take into account periglacial processes affecting the topsoil to discriminate tectonic from non-tectonic deformation. We used tephra layers in the Vestari Krubbssk&amp;#225;l and Tra&amp;#240;arger&amp;#240;i trenches as well as birch wood samples in Tra&amp;#240;arger&amp;#240;i to constrain the timing of past earthquakes. Tephra layers Hekla-3 (2971 BP) and Hekla-4 (4331&amp;#177;20 BP) are visible in the top half of all the trenches. In addition, a few younger tephra layers are visible in the top part of the trenches. In Tra&amp;#240;arger&amp;#240;i several dark layers rich in organic matter are found, including birch wood-rich layers from the Earlier Birch Period (9000-7000 BP) and the Later Birch Period (5000-2500 BP). In Vestari Krubbssk&amp;#225;l the lower halves of the trenches display mostly lacustrine deposits whereas in Tra&amp;#240;arger&amp;#240;i the lower half of the trench shows alluvial deposits overlaying coarser deposits (gravels/pebbles) most likely of late-glacial or early post-glacial origins. In addition, early Holocene tephra layers are observed in some of the trenches at both sites and may correspond to Askja-S (10800 BP), Saksunarvatn (10300 BP) and Vedde (12100 BP). These observations provide good age constraints and suggest that both the Vestari Krubbssk&amp;#225;l and Tra&amp;#240;arger&amp;#240;i trenches cover the entire Holocene.&lt;/p&gt;&lt;p&gt;Trenches at both sites show significant normal deformation in addition to strike-slip, well correlated with their larger scale topographies (pull-apart basin in Vestari Krubbssk&amp;#225;l and 45 m-high fault scarp in Tra&amp;#240;arger&amp;#240;i). We mapped layers, cracks and faults on all trench walls to build a catalogue of Holocene earthquakes. We identified events based on the upward terminations of the cracks and retrodeformation. Our results yield fewer major earthquakes than expected, suggesting that large earthquakes (around magnitude 7) are probably rare and the more typical HFF earthquakes of magnitude 6-6.5 likely produce limited topsoil deformation.[yk1]&amp;#160; Our interpretation also suggests that the Holocene slip rate [yk2]&amp;#160;for the fault section we are studying may be slower than the estimated geodetic slip rate (6 to 9 mm/yr)[yk3]&amp;#160; for the entire onshore HFF, although secondary onshore sub-parallel fault strands could accommodate part of the deformation.&lt;/p&gt;

scholarly journals Pollen-based paleoenvironmental and paleoclimatic change at Lake Ohrid (south-eastern Europe) during the past 500 ka

2016 ◽  
Vol 13 (5) ◽  
pp. 1423-1437 ◽  
Author(s):  
Laura Sadori ◽  
Andreas Koutsodendris ◽  
Konstantinos Panagiotopoulos ◽  
Alessia Masi ◽  
Adele Bertini ◽  
...  
Keyword(s):  
Lake Ohrid ◽  
Good Correspondence ◽  
Scientific Drilling ◽  
Near Eastern ◽  
Orbital Parameters ◽  
Age Model ◽  
Tephra Layers ◽  
Assemblage Zone ◽  
Yugoslavian Republic ◽  
Glacial Periods

Abstract. Lake Ohrid is located at the border between FYROM (Former Yugoslavian Republic of Macedonia) and Albania and formed during the latest phases of Alpine orogenesis. It is the deepest, the largest and the oldest tectonic lake in Europe. To better understand the paleoclimatic and paleoenvironmental evolution of Lake Ohrid, deep drilling was carried out in 2013 within the framework of the Scientific Collaboration on Past Speciation Conditions (SCOPSCO) project that was funded by the International Continental Scientific Drilling Program (ICDP). Preliminary results indicate that lacustrine sedimentation of Lake Ohrid started between 1.2 and 1.9 Ma ago. Here we present new pollen data (selected percentage and concentration taxa/groups) of the uppermost  ∼  200 m of the 569 m long DEEP core drilled in the depocentre of Lake Ohrid. The study is the fruit of a cooperative work carried out in several European palynological laboratories. The age model of this part of the core is based on 10 tephra layers and on tuning of biogeochemical proxy data to orbital parameters. According to the age model, the studied sequence covers the last  ∼  500 000 years at a millennial-scale resolution ( ∼  1.6 ka) and records the major vegetation and climate changes that occurred during the last 12 (13 only pro parte) marine isotope stages (MIS). Our results indicate that there is a general good correspondence between forested/non-forested periods and glacial–interglacial cycles of the marine isotope stratigraphy. The record shows a progressive change from cooler and wetter to warmer and drier interglacial conditions. This shift in temperature and moisture availability is visible also in vegetation during glacial periods. The period corresponding to MIS11 (pollen assemblage zone OD-10, 428–368 ka BP) is dominated by montane trees such as conifers. Mesophilous elements such as deciduous and semi-deciduous oaks dominate forest periods of MIS5 (PASZ OD-3, 129–70 ka BP) and MIS1 (PASZ OD-1, 14 ka BP to present). Moreover, MIS7 (PASZ OD-6, 245–190 ka) shows a very high interglacial variability, with alternating expansions of montane and mesophilous arboreal taxa. Grasslands (open vegetation formations requiring relatively humid conditions) characterize the earlier glacial phases of MIS12 (PASZ OD-12, 488–459 ka), MIS10 (corresponding to the central part of PASZ OD-10, 428–366 ka) and MIS8 (PASZ OD-7, 288–245 ka). Steppes (open vegetation formations typical of dry environments) prevail during MIS6 (OD-5 and OD-4, 190–129 ka) and during MIS4-2 (PASZ OD-2, 70–14 ka). Our palynological results support the notion that Lake Ohrid has been a refugium area for both temperate and montane trees during glacials. Closer comparisons with other long southern European and Near Eastern pollen records will be achieved through ongoing high-resolution studies.

Sign in / Sign up

Export Citation Format

Share Document