How Does Sedimentary Layering Affect the Generation of Tsunamis?

2009 ◽  
Author(s):  
Denys Dutykh ◽  
Fre´de´ric Dias
Keyword(s):  
Half Space ◽  
Hard Rock ◽  
Test Case ◽  
Sediment Layer ◽  
Sedimentary Deposits ◽  
Vertical Displacements ◽  
Generation Region ◽  
Sediment Layers ◽  
Parameter Values ◽  
Future Work

This article presents preliminary results on the influence of sediment layers on the process of tsunami generation. The main scope here is to demonstrate and especially quantify the effect of sedimentation on vertical displacements of the seabed due to an underwater earthquake. The effects in the far field are left for future work. The elastodynamics equations are integrated with a finite element method and the fault is modelled as a dislocation in a half-space. A comparison between two cases is performed. The first one corresponds to the classical situation of an elastic homogeneous and isotropic half-space, which is traditionally used for the generation of tsunamis. The second test case takes into account the presence of a sediment layer separating the oceanic column from the hard rock. Some important differences are revealed. We conjecture that deformations in the generation region may be amplified by sedimentary deposits, at least for some parameter values. The mechanism of amplification is studied through careful numerical simulations.

scholarly journals The δ13C, δ18O and Δ47 records in biogenic, pedogenic and geogenic carbonate types from paleosol-loess sequence and their paleoenvironmental meaning

2021 ◽  
pp. 1-17
Author(s):  
Kazem Zamanian ◽  
Alex R. Lechler ◽  
Andrew J. Schauer ◽  
Yakov Kuzyakov ◽  
Katharine W. Huntington
Keyword(s):  
Land Snail ◽  
Isotopic Signature ◽  
Sediment Layer ◽  
Isotopic Signatures ◽  
Pedogenic Carbonates ◽  
Rhine Valley ◽  
Clumped Isotope ◽  
Time Specific ◽  
Sediment Layers ◽  
Paleoenvironmental Reconstructions

Abstract Paleoenvironmental reconstructions are commonly based on isotopic signatures of a variety of carbonate types, including rhizoliths and land-snail shells, present in paleosol-loess sequences. However, various carbonate types are formed through distinct biotic and abiotic processes over various periods, and therefore may record diverging environmental information in the same sedimentological layer. Here, we investigate the effects of carbonate type on δ13C, δ18O, and clumped isotope-derived paleotemperature [T(Δ47)] from the Quaternary Nussloch paleosol-loess sequence (Rhine Valley, SW Germany). δ13C, δ18O, and T(Δ47) values of co-occurring rhizoliths (-8.2‰ to -5.8‰, -6.1‰ to -5.9‰, 12–32°C, respectively), loess dolls (-7.0‰, -5.6‰, 23°C), land-snail shells (-8.1‰ to -3.2‰, -4.0‰ to -2.2‰, 12–38°C), earthworm biospheroliths (-11‰, -4.7‰, 8°C), and “bulk” carbonates (-1.9‰ to -0.5‰, -5.6‰ to -5.3‰, 78–120°C) from three sediment layers depend systematically on the carbonate type, admixture from geogenic carbonate, and the duration of formation periods. Based on these findings, we provide a comprehensive summary for the application of the three isotopic proxies of δ13C, δ18O, and Δ47 in biogenic and pedogenic carbonates present in the same sediment layer to reconstruct paleoenvironments (e.g., local vegetation, evaporative conditions, and temperature). We conclude that bulk carbonates in Nussloch loess should be excluded from paleoenvironmental reconstructions. Instead, pedogenic and biogenic carbonates should be used to provide context for interpreting the isotopic signature for detailed site- and time-specific paleoenvironmental information.

scholarly journals Detection and Identification of Sediment Layer to Discover the Marine Mineral Resources Potential in Aruah Islands

2021 ◽  
Vol 9 (1) ◽  
pp. 70
Author(s):  
Pareng Rengi ◽  
Ulil Amri ◽  
Tomi Ramadona ◽  
Ediar Usman ◽  
Bustari Bustari
Keyword(s):  
Sediment Sample ◽  
Single Channel ◽  
Low Frequency ◽  
Mineral Resources ◽  
Coarse Sand ◽  
Sediment Layer ◽  
Sediment Thickness ◽  
Seismic Profiles ◽  
Detection And Identification ◽  
Sediment Layers

<p>Aruah Islands is located on an international shipping line adjacent to Malaysia. The important aspect in borderline management is the maritime resource potential, one of which is sea minerals. In order to dig the information about marine mineral resources in Aruah Islands, a high-resolution seismic reflection with low frequency was applied, which capable to detect the depth and identify the sedimentary layers clearly and accurately. The depth of water and sediment layers were detected using an echosounder, reason Navi sound type 210 with a tow fish 100 kHz and shallow seismic boomer with a single channel type and wave energy 200 Joules. Gravity core and grab sampler were used to collect the sediment sample. There were three stages on seismic interpretation: sequence analysis, facies analysis, and reflection character identification. Furthermore, sediments containing coarse sand-sized minerals were observed using a microscope. The measurement result of Aruah Islands water depth was ranging from 0-80 m, the deepest part is on the Northern of Batu Mandi island which was 80 m depth. Seismic profiles indicated that the upper layer of tertiary sedimentary as the youngest rocks. Based on sediment thickness, the thickest area was found on the Western (approx. 50 m) and the Northern (approx. 32 m). In line with the island’s Southern part condition, which was plain or shallow sea exposure, the Southeastern island sediment thickness ranged only about 10-18 m. Generally, based on the analyzed sediment sample, quartz was the main mineral found, which was 60-80% of the composition. Other minerals were zircon, tin, hematite, magnetite, limonite, biotite, and dolomite.</p>

Torsional damping of a back-to-back gearbox rig: Experimental measurements and frequency domain modelling

2002 ◽  
Vol 216 (2) ◽  
pp. 157-168 ◽  
Author(s):  
S J Drew ◽  
B J Stone
Keyword(s):  
Frequency Domain ◽  
Natural Frequencies ◽  
Model Parameters ◽  
Modal Damping ◽  
Torsional Damping ◽  
Analysis Of Results ◽  
Torsional Frequency ◽  
Signal Processing Methods ◽  
Parameter Values ◽  
Future Work

This paper is concerned with the experimental measurement and modelling of the torsional damping levels of a back-to-back gearbox rig. The aims of the investigation were to experimentally measure and analyse modal damping levels for the first nine torsional natural frequencies; to optimize damping parameters for modelling and to assess any limitations of the models for future work. Standard signal processing methods were used to determine modal damping levels from measured torsional frequency responses, with good confidence in the results. A damping sensitivity analysis for the two frequency domain receptance (FDR) models was used to determine optimum damping parameter values. Damping levels for six of nine natural frequencies were well matched with the experimental data. Discrepancies at other frequencies were attributed mainly to torsional-transverse coupling, present in the rig but not the model. Analysis of results for the ninth natural frequency determined a very low level of damping for the gearbox. It was also concluded that the model parameters may be used with confidence in a time domain receptance model for future investigations related to the test gearbox damping.

Closed-Form Solutions of the Elastic Half Space due to a Line Heat Source

2014 ◽  
Vol 638-640 ◽  
pp. 2082-2091
Author(s):  
John C.C. Lu ◽  
Feng Tsai Lin
Keyword(s):  
Heat Source ◽  
Closed Form ◽  
Half Space ◽  
Hankel Transform ◽  
Elastic Half Space ◽  
Line Heat Source ◽  
Closed Form Solutions ◽  
Line Sink ◽  
Vertical Displacements ◽  
Thermoelastic Response

Thermoelastic response due to a line heat source is analog to poroelastic reaction caused by a fluid line sink. In this study, the strata are modeled as a thermoelastic or poroelastic half space bounded by horizontal surface in the mathematical model. Thermomechanics and poromechanics are applied on the formulation of basic governing equations, and an analogy is drawn to show the similarity. Using Hankel transform technique and approaching symbolic integral through Mathematica, the closed-form solutions of the horizontal and vertical displacements due to a fluid line sink are obtained. The displacements produced by the line heat source are described through analog quantities between thermoelasticity and poroelasticity. The solutions can be applied to dewater operations and build waste repository.

A Analysis and Research on the Methods of Object Oriented Software Testing

2013 ◽  
Vol 709 ◽  
pp. 616-619
Author(s):  
Jing Chen
Keyword(s):  
Genetic Algorithm ◽  
Genetic Algorithms ◽  
Test Data ◽  
Object Oriented ◽  
Automatic Generation ◽  
Test Case Generation ◽  
Test Case ◽  
Test Cases ◽  
Path Coverage ◽  
Parameter Values

This paper proposes a genetic algorithm-based method to generate test cases. This method provides information for test case generation using state machine diagrams. Its feature is realizing automation through fewer generated test cases. In terms of automatic generation of test data based on path coverage, the goal is to build a function that can excellently assess the generated test data and guide the genetic algorithms to find the targeting parameter values.

Minimum Test Case for Discrete-Type Software Reliability Testing by Stratified Sampling

2012 ◽  
Vol 263-266 ◽  
pp. 1874-1879
Author(s):  
Qiu Ying Li ◽  
Lei Luo
Keyword(s):  
Software Reliability ◽  
Traditional Approach ◽  
Simple Random Sampling ◽  
Stratified Sampling ◽  
Necessary Condition ◽  
Test Case ◽  
Test Cases ◽  
Operational Profile ◽  
Future Work ◽  
Discrete Type

The traditional approach for generating software reliability test cases according to operational profile (OP) can be regarded as a simple random sampling. The stratified sampling is a complex but more accurate sampling approach which can make the sampling results more accurate and less variance by dividing the population into several subsets and randomly sampling from each subset respectively. Firstly, this paper introduced the traditional method which can be used to determine the number of test cases in the discrete-type software reliability demonstration testing. Secondly, the necessary condition for the minimum test case based on the stratified sampling was studied. Then a new approach was proposed and its principle was analyzed for determining the minimum test case of the discrete-type software by using the stratified sampling. Finally, the future work was discussed.

RECONSTRUCTION OF LAYERED ELASTIC BOTTOM CHARACTERISTICS BY THE FREQUENCY DEPENDENCE OF SOUND REFLECTIVITY

2001 ◽  
Vol 09 (04) ◽  
pp. 1475-1484 ◽  
Author(s):  
VLADIMIR N. FOKIN ◽  
MARGARETE S. FOKINA
Keyword(s):  
Frequency Dependence ◽  
Half Space ◽  
Simulated Data ◽  
Elastic Half Space ◽  
Ocean Bottom ◽  
Sediment Layer ◽  
Elastic Bottom ◽  
Sea Bottom ◽  
Sound Reflection ◽  
Grazing Angles

The relation between the sound reflection losses measured at fixed grazing angles and the characteristics of the sediment layer and underlying half-space is considered. Based on this relation, a method of the reconstruction of the sea bottom characteristics is developed for a ocean bottom consisting of a single sediment layer overlaying a semi-infinite elastic half-space. Using this bottom model, the reconstruction of the characteristics of a layered elastic bottom is performed from the numerically simulated data with induced synthetic error.

scholarly journals Approximate formula for the H/V ratio of Rayleigh waves in incompressible orthotropic half-spaces coated by a thin elastic layer

2017 ◽  
Vol 39 (4) ◽  
pp. 365-374
Author(s):  
Pham Chi Vinh ◽  
Tran Thanh Tuan ◽  
Le Thi Hue
Keyword(s):  
Free Surface ◽  
Rayleigh Wave ◽  
Half Space ◽  
Rayleigh Waves ◽  
Elastic Layer ◽  
Approximate Formula ◽  
Elastic Half Space ◽  
Displacement Amplitude ◽  
Vertical Displacements ◽  
Thin Elastic Layer

This paper is concerned with the propagation of Rayleigh waves in an incompressible orthotropic elastic half-space coated with a thin incompressible orthotropic elastic layer. The main purpose of the paper is to establish an approximate formula for the Rayleigh wave H/V ratio (the ratio between the amplitudes of the horizontal and vertical displacements of Rayleigh waves at the traction-free surface of the layer). First, the relations between the traction amplitude vector and the displacement amplitude vector of Rayleigh waves at two sides of the interface between the layer and the half-space are created using the Stroh formalism and the effective boundary condition method. Then, an approximate formula for the Rayleigh wave H/V ratio of third-order in terms of dimensionless thickness of the layer has been derived by using these relations along with the Taylor expansion of the displacement amplitude vector of the thin layer at its traction-free surface. It is shown numerically that the obtained formula is a good approximate one. It can be used for extracting mechanical properties of thin films from measured values of the  Rayleigh wave H/V ratio.

Directly Dating Sedimentary Rocks

2006 ◽  
Vol 12 ◽  
pp. 77-105 ◽  
Author(s):  
E. Troy Rasbury ◽  
Jennifer M. Cole
Keyword(s):  
Critical Evaluation ◽  
Sedimentary Rocks ◽  
Black Shales ◽  
Depositional Environments ◽  
Radiometric Dating ◽  
Geochemical Behavior ◽  
Sedimentary Deposits ◽  
Future Work ◽  
Isotope Systematics

This contribution seeks to provide a summary of radiometric dating techniques that are currently applicable to Phanerozoic sedimentary deposits and therefore relevant to paleontologists. First we overview the assumptions necessary for radiometric dating and introduce isochrons and concordia diagrams as methods for calculating ages and evaluating isotope systematics. We then focus on the four most promising systems: U-Pb dating of carbonates, Re-Os dating of black shales, and U-Pb and Lu-Hf dating of phosphates. We review expected geochemical behavior of daughter and parent isotopes in the context of both marine and terrestrial depositional environments. A critical evaluation of previously published ages and potential directions for future work are provided.

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