Historic large earthquake-induced soft sediment deformation features in the Sub-Himalayan Doon valley

1998 ◽  
Vol 135 (2) ◽  
pp. 269-281 ◽  
Author(s):  
RAKESH MOHINDRA ◽  
V. C. THAKUR
Keyword(s):  
Flame Structure ◽  
Large Earthquake ◽  
Fine Sand ◽  
Great Earthquake ◽  
Soft Sediment ◽  
Doon Valley ◽  
Deformation Features ◽  
Sediment Deformation ◽  
Soft Sediment Deformation ◽  
Drop Structure

Well-preserved soft sediment deformation structures were observed at six sites along the course of the Baldi Nadi in the Doon valley of the Garhwal Himalaya. These deformed structures lie in mid- and side-channel bars of the braided Baldi stream. The deformed sediments are composed of unconsolidated alternations of mud, silt and very fine sand with ripple lamination. Deformation is restricted to a single stratigraphic layer bounded by undeformed beds, suggesting synsedimentary deformation. These features can be traced laterally along the course of the braided Baldi Nadi, over a distance of 7 km in isolated bar deposits at one stratigraphic level, 1.5–2 m above the lean season water level. The deformed features display over-steepening of sedimentary strata, folding, graben-type faulting, plume-like intrusion, flame structure, slumping related to disrupted bedding and pear-drop structure. The style and type of deformation vary considerably in the different segments within a single bed, while the intensity may be same at one site. The deformation features of the Baldi Nadi are interpreted to be the product of liquefaction and fluidization of unconsolidated mud and silt during historic earthquake(s), related to the past seismic activity of the Main Boundary Thrust (MBT) and the Himalayan Frontal Fault (HFF) or blind thrust. The intensity of deformation provides an opportunity to reconstruct the felt area magnitude of large historic earthquake(s) and helps in tracing the palaeoearthquake epicentre. The observed earthquake-induced soft sediment deformation features indicate that in addition to the 1905 ‘great’ earthquake, the Doon valley was also affected by historic earthquake(s) of magnitude ∼7, possibly corresponding to those of 1803 and/or 1720, if not older.

scholarly journals Paleoliquefaction Studies and the Evaluation of Seismic Hazard

Geosciences ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 311 ◽  
Author(s):  
Tuttle ◽  
Hartleb ◽  
Wolf ◽  
Mayne
Keyword(s):  
Background Information ◽  
Seismic Zone ◽  
Soft Sediment ◽  
Source Characterization ◽  
Ground Shaking ◽  
Earthquake Hazard Assessment ◽  
Seismic Source Models ◽  
Deformation Features ◽  
Sediment Deformation ◽  
Soft Sediment Deformation

Recent and historical studies of earthquake-induced liquefaction, as well as paleoliquefaction studies, demonstrate the potential usefulness of liquefaction data in the assessment of the earthquake potential of seismic sources. Paleoliquefaction studies, along with other paleoseismology studies, supplement historical and instrumental seismicity and provide information about the long-term behavior of earthquake sources. Paleoliquefaction studies focus on soft-sediment deformation features, including sand blows and sand dikes, which result from strong ground shaking. Most paleoliquefaction studies have been conducted in intraplate geologic settings, but a few such studies have been carried out in interplate settings. Paleoliquefaction studies provide information about timing, location, magnitude, and recurrence of large paleoearthquakes, particularly those with moment magnitude, M, greater than 6 during the past 50,000 years. This review paper presents background information on earthquake-induced liquefaction and resulting soft-sediment deformation features that may be preserved in the geologic record, best practices used in paleoliquefaction studies, and application of paleoliquefaction data in earthquake source characterization. The paper concludes with two examples of regional paleoliquefaction studies—in the Charleston seismic zone and the New Madrid seismic zone in the southeastern and central United States, respectively—which contributed to seismic source models used in earthquake hazard assessment.

scholarly journals Soft sediment deformation features in Dauki Fault region: Evidence of paleoearthquakes, Shillong Plateau, NE India

2021 ◽  
Author(s):  
B.V Lakshmi ◽  
Praveen B. Gawali
Keyword(s):  
Urban Areas ◽  
Late Quaternary ◽  
Soft Sediment ◽  
Shillong Plateau ◽  
Deformation Structures ◽  
Regional Deformation ◽  
Ne India ◽  
Deformation Features ◽  
Sediment Deformation ◽  
Soft Sediment Deformation

Abstract The northeastern region (NER) of India has a number of complex regional geological structures, out of which the Dauki fault (DF) is a prominent one. The E-W trending reverse DF, which is referred to go through the southern margin of Shillong Plateau (SP), have played major role in the regional deformation of the adjoining areas and was believed to be active during the Late Quaternary time. Previous paleoseismological studies conducted on the eastern and western part of the DF, Bangladesh, revealed that the fault ruptured in AD 849–920 and AD 1548 respectively. However there were no studies on the DF from southern side of the SP, India. For the first time, from Indian side, soft sediment deformation structures (SSDS) are reported from five trenches in and around the DF zone, SP. Close to the Dauki village, five trenches in the eastern part of the DF, SP, show presence of micro faulting, sand dykes, disturbed strata, and water escape structures. The detailed investigation of SSDS indicates that the origin for deformation is seismic trigger. The 14C AMS dating of deformation structures generated coseismically by earthquakes suggest three seismic events occurred between 130 and 920 year BP, 5415 to 9140 year BP, and at about 4285 year BP. This study confirms that DF is indeed active, at least, since the mid-Holocene. More trenching and dating of seismically induced deformation features are needed to accurately calculate the recurrence interval of major earthquakes that can strike the fast-expanding urban areas in India and Bangladesh.

3D soft-sediment deformation structures: evidence for Quaternary seismicity in the Madrid basin, Spain

Terra Nova ◽  
1997 ◽  
Vol 9 (5) ◽  
pp. 208-212 ◽  
Author(s):  
P.G. Silva ◽  
J.C. Canaveras ◽  
S. Sanchez-Moral ◽  
J. Lario ◽  
E. Sanz
Keyword(s):  
Soft Sediment ◽  
Deformation Structures ◽  
Sediment Deformation ◽  
Soft Sediment Deformation

Dead Sea shoreline facies with seismically-induced soft-sediment deformation structures, Israel

2000 ◽  
Vol 49 (4) ◽  
pp. 197-214 ◽  
Author(s):  
Dan Bowman ◽  
Dorit Banet-Davidovich ◽  
Hendrik J. Bruins ◽  
Johannes Van der Plicht
Keyword(s):  
Dead Sea ◽  
Soft Sediment ◽  
Deformation Structures ◽  
Sediment Deformation ◽  
Soft Sediment Deformation

scholarly journals Lacustrine Slope-Related Soft-Sediment Deformation Structures in the Cretaceous Gyeokpori Formation, Buan Area, SW Korea, and Volcanism-Induced Seismic Shocks as Their Possible Trigger

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 721
Author(s):  
Ukhwan Byun ◽  
A.J. (Tom) van Loon ◽  
Kyoungtae Ko
Keyword(s):  
Facies Analysis ◽  
Deformation Mechanisms ◽  
Volcanic Area ◽  
Cohesive Sediments ◽  
Soft Sediment ◽  
Deformation Structures ◽  
Sediment Deformation ◽  
Soft Sediment Deformation ◽  
Siliciclastic Rocks ◽  
Sediment Layers

The Gyeokpori Formation in the Buan volcanic area primarily contains siliciclastic rocks interbedded with volcanoclastics. These sediments are characterized by a variety of soft-sediment deformation structures (SSDS). The SSDS in the Gyeokpori Formation are embedded in poorly sorted conglomerates; slump folds are also present in the formation. The deformation mechanisms and triggers causing the deformation are not yet clear. In the present study, the trigger of the SSDS in the Gyeokpori Formation was investigated using facies analysis. This included evaluation of the reworking process of both cohesive and non-cohesive sediments. The analysis indicates that the SSDS are directly or indirectly associated with the alternation of conglomerates and mud layers with clasts. These layers underwent non-cohesive and cohesive deformation, respectively, which promoted SSDS formation. The slump folds were controlled by the extent of cohesive and non-cohesive deformation experienced by the sediment layers in the slope environment. The SSDS deformation style and morphology differ, particularly in the case of reworking by slump activity. This study contributes to the understanding of lacustrine slope-related soft-sediment deformation structures.

scholarly journals MULTIFRACTAL ANALYSIS OF SEISMICALLY INDUCED SOFT-SEDIMENT DEFORMATION STRUCTURES IMAGED BY X-RAY COMPUTED TOMOGRAPHY

Fractals ◽  
2018 ◽  
Vol 26 (01) ◽  
pp. 1850018 ◽  
Author(s):  
YOSHITO NAKASHIMA ◽  
JUNKO KOMATSUBARA
Keyword(s):  
Computed Tomography ◽  
Multifractal Analysis ◽  
Flow Model ◽  
Soft Sediment ◽  
X Ray ◽  
Deformation Structures ◽  
X Ray Computed ◽  
Sediment Deformation ◽  
Soft Sediment Deformation ◽  
Iron Bearing

Unconsolidated soft sediments deform and mix complexly by seismically induced fluidization. Such geological soft-sediment deformation structures (SSDSs) recorded in boring cores were imaged by X-ray computed tomography (CT), which enables visualization of the inhomogeneous spatial distribution of iron-bearing mineral grains as strong X-ray absorbers in the deformed strata. Multifractal analysis was applied to the two-dimensional (2D) CT images with various degrees of deformation and mixing. The results show that the distribution of the iron-bearing mineral grains is multifractal for less deformed/mixed strata and almost monofractal for fully mixed (i.e. almost homogenized) strata. Computer simulations of deformation of real and synthetic digital images were performed using the egg-beater flow model. The simulations successfully reproduced the transformation from the multifractal spectra into almost monofractal spectra (i.e. almost convergence on a single point) with an increase in deformation/mixing intensity. The present study demonstrates that multifractal analysis coupled with X-ray CT and the mixing flow model is useful to quantify the complexity of seismically induced SSDSs, standing as a novel method for the evaluation of cores for seismic risk assessment.

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