Earthquake-induced soft-sediment deformations and seismically amplified erosion rates recorded in varved sediments of Koycegiz Lake (SW Turkey)

Date

2016-06-01

Author

Avşar, Ulaş
Avsar, Ozgur
Schmidt, Sabine

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

219
views

0
downloads

Earthquake-triggered landslides amplify erosion rates in catchments, i.e., catchment response (CR) to seismic shocks. In addition to historical eyewitness accounts of muddy rivers implying CRs after large earthquakes, several studies have quantitatively reported increased sediment concentrations in rivers after earthquakes. However, only a few paleolimnological studies could detect CRs within lacustrine sedimentary sequences as siliciclastic-enriched intercalations within background sedimentation. Since siliciclastic-enriched intercalations can easily be of nonseismic origin, their temporal correlation with nearby earthquakes is crucial to assign a seismic triggering mechanism. In most cases, either uncertainties in dating methods or the lack of recent seismic activity has prevented reliable temporal correlations, making the seismic origin of observed sedimentary events questionable. Here we attempt to remove this question mark by presenting sedimentary traces of CRs in the 370-year-long varved sequence of Koycegiz Lake (SW Turkey) that we compare with estimated peak ground acceleration (PGA) values of several nearby earthquakes. We find that earthquakes exceeding estimated PGA values of similar to 20 cm/s(2) can induce soft-sediment deformations, while CRs seem only to be triggered by PGA levels higher than 70 cm/s(2). In Koycegiz Lake, CRs produce Cr-and Ni-enriched sedimentation due to the seismically mobilized soils derived from ultramafic rocks in the catchment. Given the varve chronology, the residence time of the seismically mobilized material in the catchment is determined to be 5 to 10 years.

Subject Keywords

North Anatolian Fault, Mass-Wasting Events, Paleoseismic Record, Historic Earthquakes, Slip Distribution, Surface Rupture, Alpine Fault, Pleistocene, Landslides, Location

URI

https://hdl.handle.net/11511/36615

Journal

JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH

DOI

https://doi.org/10.1002/2016j13012820

Collections

Department of Geological Engineering, Article

Suggestions

OpenMETU
Core

SEISMIC HAZARD ANALYSIS WITH RANDOMLY LOCATED SOURCES Yücemen, Mehmet Semih (1994-03-01) Demarcation of areal and linear seismic sources involves a certain degree of uncertainty and this should be reflected in the final seismic hazard results. The uncertainty associated with the description of the geographical coordinates of a source zone boundary is modeled by introducing the concept of 'random boundary', where the location of the boundary is assumed to exhibit a spatial bivariate Gaussian distribution. Here the mean vector denotes the best estimate of location and the variance reflects the ma...
Seismic Intensity Maps for the Eastern Part of the North Anatolian Fault Zone (Turkey) Based on Recorded and Simulated Ground-Motion Data Askan, Aysegul; Karim Zadeh Naghshineh, Shaghayegh; Bilal, Mustafa (2017-01-01) Seismic intensity maps are employed globally in the aftermaths of earthquakes for rapid response purposes. These maps involve correlations between intensity and peak ground-motion values. In this study, we focus on eastern sections of the North Anatolian fault zone (NAFZ). The eastern segments of the NAFZ are less investigated and have sparse seismic networks compared with western ones. In particular, we study Erzincan, which is a small city in eastern Turkey, located in the conjunction of three active faul...
Fault-based probabilistic seismic hazard assessment of the eastern Makran subduction and the Chaman transform fault, Pakistan: Emphasis on the source characterization of megathrust Shah, Syed Tanvir; Özacar, Atilla Arda; Gülerce, Zeynep (Elsevier BV, 2021-01-01) Seismic source characterization (SSC) for probabilistic seismic hazard assessment (PSHA) in regions characterized by subduction megathrust involves a considerable ambiguity. Lack of detailed geologic, seismic, and geodetic data increases the uncertainties. The enigma is enhanced in regions where thin-skinned accretionary prism faults are part of active deformation. In this study, a planar SSC model for seismically active eastern Makran subduction zone, its associated accretionary prism faults and Chaman tra...
Earthquake imprints on a lacustrine deltaic system: The Kurk Delta along the East Anatolian Fault (Turkey) Hubert-Ferrari, Aurelia; El-Ouahabi, Meriam; Garcia-Moreno, David; Avşar, Ulaş; Altinok, Sevgi; Schmidt, Sabine; Fagel, Nathalie; Cagatay, M. Namik (2017-08-01) Deltas contain sedimentary records that are not only indicative of water-level changes, but also particularly sensitive to earthquake shaking typically resulting in soft-sediment-deformation structures. The Kurk lacustrine delta lies at the south-western extremity of Lake Hazar in eastern Turkey and is adjacent to the seismogenic East Anatolian Fault, which has generated earthquakes of magnitude 7. This study re-evaluates water-level changes and earthquake shaking that have affected the Kurk Delta, combinin...
Seismic testing of a scaled roller-compacted-concrete gravity dam Gharibdoust, Ali; Binici, Barış; Department of Civil Engineering (2016) Within the last half-century, seismic response analysis of concrete gravity dams has been extensively studied. Studies reveal that two types of failure modes prevail in the form of dam body cracking or base slide. The literature lacks the conditions that clearly differentiate the two failure types. In this context a state of the art single degree of freedom pseudo-dynamic testing was developed to assess the gravity dam response on smooth foundation interface. Three different hazard levels of earthquake name...

Citation Formats

U. Avşar, O. Avsar, and S. Schmidt, “Earthquake-induced soft-sediment deformations and seismically amplified erosion rates recorded in varved sediments of Koycegiz Lake (SW Turkey),” JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, pp. 4767–4779, 2016, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/36615.