scholarly journals Supplementary material to "Slow build-up of turbidity currents triggered by a moderate earthquake in the Sea of Marmara"

2021 ◽  
Author(s):  
Pierre Henry ◽  
Sinan Özeren ◽  
Nurettin Yakupoğlu ◽  
Ziyadin Çakir ◽  
Emmanuel de Saint-Léger ◽  
...  
Keyword(s):  
Turbidity Currents ◽  
Sea Of Marmara ◽  
Moderate Earthquake ◽  
Supplementary Material

Slow build-up of turbid currents triggered by a moderate earthquake in the Sea of Marmara

2020 ◽  
Author(s):  
Pierre Henry ◽  
M Sinan Özeren ◽  
Nurettin Yakupoğlu ◽  
Ziyadin Çakir ◽  
Emmanuel de Saint-Léger ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Debris Flows ◽  
Background Level ◽  
Signal Strength ◽  
Normal Operation ◽  
Turbidity Currents ◽  
Central Basin ◽  
Sea Of Marmara ◽  
Moderate Earthquake ◽  
Mud Flow

<p>Earthquake-induced submarine slope destabilization is known to cause debris flows and turbidity currents. These also interact with currents caused by tsunami and seiches resulting in deposits with specific sedimentological characteristics, turbidite-homogenites being a common example. Data on the deep-sea hydrodynamic events following earthquakes are, however, limited. An instrumented frame deployed at the seafloor in the Sea of Marmara Central Basin recorded some of the consequences of a magnitude 5.8 earthquake that occurred Sept 26, 2019 at 10-12 km depth without causing any significant tsunami. The instrumentation comprises a Digiquartz® pressure sensor recording at 5 s interval and a 1.9-2 MHz Doppler recording current meter set 1.5 m above the seafloor and recording at 1-hour interval. The device was deployed at 1184 m depth on the floor of the basin near the outlet of a canyon, 5 km from the epicenter. Chirp sediment sounder profiles indicate a depositional fan or lobe is present at this location. The passing of the seismic wave was recorded by the pressure sensor, but little other perturbation is recorded until 25 minutes later when the instrument, probably hit by a mud flow, tilts by 65° in about 15 seconds. Over the following 10 hours the tilted instrument records bursts of current of variable directions. The last burst appears to be the strongest with velocities in the 20-50 cm/s range, causing enough erosion to free the device from the mud and allowing the buoyancy attached to the upper part of the frame to straighten it back to its normal operation position. Then, the current, flowing down along the canyon axis, progressively decays to background level (≈2 cm/s) in 8 hours. Doppler signal backscatter strength is a proxy for turbidity, sensitive to sand-size suspended particles. Signal strength increased to high values during the event (max -7.6 dB from a background value of -40dB) and decayed over the next three days. These observations show that even a moderate earthquake can trigger a complex response involving mud flows and turbidity currents. We infer simultaneous slope failures at various locations may produce complex current patterns and cause build-up of kinetic energy over several hours.</p>

scholarly journals Slow build-up of turbidity currents triggered by a moderate earthquake in the Sea of Marmara

2021 ◽  
Author(s):  
Pierre Henry ◽  
Sinan Özeren ◽  
Nurettin Yakupoğlu ◽  
Ziyadin Çakir ◽  
Emmanuel de Saint-Léger ◽  
...  
Keyword(s):  
Sediment Resuspension ◽  
Turbidity Current ◽  
Turbidity Currents ◽  
Central Basin ◽  
Sea Of Marmara ◽  
Sedimentary Records ◽  
Strong Current ◽  
Moderate Earthquake ◽  
Basin Floor ◽  
Hydrodynamic Processes

Abstract. Earthquake-induced submarine slope destabilization is known to cause debris flows and turbidity currents, but the hydrodynamic processes associated with these events remain poorly understood. Records are scarce and this notably limits our ability to interpret marine paleoseismological sedimentary records. An instrumented frame comprising a pressure recorder and a Doppler recording current meter deployed at the seafloor in the Sea of Marmara Central Basin recorded consequences of a MW = 5.8 earthquake occurring Sept 26, 2019 and of a Mw = 4.7 foreshock two days before. The smaller event caused sediment resuspension but no strong current. The larger event triggered a complex response involving a mud flow and turbidity currents with variable velocities and orientations, which may result from multiple slope failures. A long delay of 10 hours is observed between the earthquake and the passing of the strongest turbidity current. The distance travelled by the sediment particles during the event is estimated to several kilometres, which could account for a local deposit on a sediment fan at the outlet of a canyon, but not for the covering of the whole basin floor. We show that after a moderate earthquake, delayed turbidity current initiation may occur, possibly by ignition of a cloud of resuspended sediment. Some caution is thus required when tying seismoturbidites with earthquakes of historical importance. However, the horizontal extent of the deposits should remain indicative of the size of the earthquake.

Volcaniclastic deposits and sedimentation processes around volcanic ocean islands: the central Azores

2021 ◽  
pp. SP520-2021-62
Author(s):  
Yu-Chun Chang ◽  
Neil C. Mitchell ◽  
Thor H. Hansteen ◽  
Julie C. Schindlbeck-Belo ◽  
Armin Freundt
Keyword(s):  
Volcanic Glass ◽  
Sedimentary Facies ◽  
Turbidity Currents ◽  
Content Type ◽  
Core Logging ◽  
Supplementary Material ◽  
Geochemical Analyses ◽  
Lithological Composition ◽  
Volcaniclastic Deposits ◽  
Ocean Islands

AbstractGeological histories of volcanic ocean islands can be revealed by the sediments shed by them. Hence there is an interest in studying cores of volcaniclastic sediments that are particularly preserved in the many flat-floored basins lying close to the Azores islands. We analyse four gravity cores collected around the central group of the islands. Three sedimentary facies (F1-F2a, F2b) are recognized based on visual core logging, particle morphometric and geochemical analyses. F1 is clay-rich hemipelagite comprising homogeneous mud with mottled structures from bioturbation. F2a and F2b are both clay-poor volcaniclastic deposits, which are carbonate-rich and carbonate-poor, respectively. More biogenic carbonate in F2a reflects the incorporation of unconsolidated calcareous material from island shelves or bioturbation. Within F2a and F2b we identify deposits emplaced by pyroclastic fallout, primary or secondary turbidity currents by combining multiple information from lithological composition, sedimentary structures, chemical composition of volcanic glass shards and morphometric characteristics of volcanic particles. Primary volcaniclastic sediments were found in all four cores, echoing activity known to have occurred up to historical times on the adjacent islands. These preliminary results suggest that greater details of geological events could be inferred for other volcanic islands by adopting a similar approach to core analysis.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5602176

Designing Workbook for Teaching Writing Descriptive Text Based on Scientific Approach

2019 ◽  
Vol 1 (2) ◽  
pp. 59
Author(s):  
Indah Pratiwi ◽  
Yanti Sri Rezeki
Keyword(s):  
Teaching Writing ◽  
English Teacher ◽  
Design Development ◽  
Seventh Grade ◽  
Internal Evaluation ◽  
Writing Ability ◽  
Good Book ◽  
Scientific Approach ◽  
Supplementary Material ◽  
Analysis Design

This research aims to design workbook based on the scientific approach for teaching writing descriptive text. This research was conducted on the seventh-grade students of SMPN 24 Pontianak. The method of this research is ADDIE (Analysis, Design, Development, Implementation, and Evaluation) with the exclusion of Implementation and Evaluation phases. This material was designed as supplementary material to support the course book used especially in teaching writing of descriptive text. The respondents in this research were the seventh-grade students and an English teacher at SMPN 24 Pontianak. In this research, the researchers found that workbook based on scientific approach fulfilled the criteria of the good book to teach writing descriptive text. The researchers conducted an internal evaluation to see the usability and the feasibility of the workbook. The result of the evaluation is 89%. It showed that the workbook is feasible to be used by students as the supplementary material to support the main course book and help the students improve their writing ability in descriptive text.

Catalytic Fluorination of Boron Compounds at a Bismuth Redox Platform

2019 ◽  
Author(s):  
Oriol Planas ◽  
Feng Wang ◽  
Markus Leutzsch ◽  
Josep Cornella
Keyword(s):  
Transition Metal ◽  
Main Group ◽  
Group Element ◽  
Oxidation States ◽  
Boron Compounds ◽  
Main Text ◽  
Main Group Element ◽  
Rational Ligand Design ◽  
Supplementary Material

The ability of bismuth to maneuver between different oxidation states in a catalytic redox cycle, mimicking the canonical organometallic steps associated to a transition metal, is an elusive and unprecedented approach in the field of homogeneous catalysis. Herein we present a catalytic protocol based on bismuth, a benign and sustainable main-group element, capable of performing every organometallic step in the context of oxidative fluorination of boron compounds; a territory reserved to transition metals. A rational ligand design featuring hypervalent coordination together with a mechanistic understanding of the fundamental steps, permitted a catalytic fluorination protocol based on a Bi(III)/Bi(V) redox couple, which represents a unique example where a main-group element is capable of outperforming its transition metal counterparts.<br>A main text and supplementary material have been attached as pdf files containing all the methodology, techniques and characterization of the compounds reported.<br>

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