Mild Displacements of Boulders during the 2019 Ridgecrest Earthquakes

2020 ◽  
Vol 110 (4) ◽  
pp. 1579-1588 ◽  
Author(s):  
Norman H. Sleep ◽  
Susan E. Hough
Keyword(s):  
Seismic Waves ◽  
Surface Rupture ◽  
Dynamic Stresses ◽  
Flat Surfaces ◽  
Source Effects ◽  
Organic Debris ◽  
Wagon Wheel ◽  
Mechanical Models ◽  
The Coefficient Of Friction ◽  
Fault Trace

ABSTRACT Strong seismic waves from the July 2019 Ridgecrest, California, earthquakes displaced rocks in proximity to the M 7.1 mainshock fault trace at several locations. In this report, we document large boulders that were displaced at the Wagon Wheel Staging Area (WWSA), approximately 4.5 km southeast of the southern terminus of the large M 6.4 foreshock rupture (hereafter “the large foreshock”) and 9 km southwest of the nearest approach of the M 7.1 mainshock surface rupture. Some boulders appear to have slid along essentially flat surfaces, which suggest that dynamic stresses overcame the coefficient of friction. Other boulders appear to have rocked within their sockets. In both cases, we use simple mechanical models to estimate total peak dynamic accelerations between 0.5 and 1g, commensurate with modified Mercalli intensity 9. It is unclear if the strongest shaking at this location occurred during the large foreshock or the M 7.1 mainshock. The inferred accelerations are higher than predicted mainshock ground motions at WWSA, although local high accelerations could have been generated by path, site, or source effects. Gaps between boulders and their sockets are easily visible in the immediate aftermath of earthquakes and provide a quick indication of strong shaking. More importantly, the gaps quickly fill with surficial organic debris, including seeds and leaves of the year, that quickly become entombed. Boulders may thus potentially be extracted to examine gap fillings associated with past earthquakes, providing a new datable paleoseismic method.

scholarly journals MEASURING THE COSEISMIC DISPLACEMENTS OF 2010 Ms7.1 Yushu EARTHQUAKE BY USING SAR AND HIGH RESOLUTION OPTICAL SATELLITE IMAGES

2017 ◽  
Vol XLII-2/W7 ◽  
pp. 665-670 ◽  
Author(s):  
L. Zhang ◽  
J. Wu ◽  
F. Shi
Keyword(s):  
Image Matching ◽  
Seismic Waves ◽  
Image Interpretation ◽  
Optical Image ◽  
Rupture Zone ◽  
Surface Rupture ◽  
Yushu Earthquake ◽  
Seismic Displacement ◽  
Surface Rupture Zone ◽  
Seismic Displacements

After the 2010, Mw7.1, Yushu earthquake, many researchers have conducted detail investigations of the surface rupture zone by optical image interpretation, field surveying and inversion of seismic waves. However, how larger of the crustal deformation area caused by the earthquake and the quantitative co-seismic displacements are still not available. In this paper, we first take advantage of D-InSAR, MAI, and optical image matching methods to determine the whole co-seismic displacement fields. Two PALSAR images and two SPOT5 images before and after the earthquake are processed and the co-seismic displacements at the surface rupture zone and far field are obtained. The results are consistent with the field investigations, which illustrates the rationality of the application of optical image matching technology in the earthquake.

Study on Isolation Device for Decrease of Displacement by Using Control of Friction

2007 ◽  
Author(s):  
Masanori Shintani ◽  
Naoya Taguchi
Keyword(s):  
Coefficient Of Friction ◽  
Frictional Force ◽  
Seismic Waves ◽  
Simulation Analysis ◽  
Relative Displacement ◽  
Analysis Model ◽  
Restoring Force ◽  
Seismic Isolator ◽  
Compression Spring ◽  
The Coefficient Of Friction

This paper deals with reduction of horizontal relative displacement by using a frictional force for a seismic isolator. First, a compression spring is attached to the base. Next, a slope plate is superimposed on it. The frictional force acts on the slope plate. The restoring-force is given to the seismic isolator by the compression spring attached to the base. In the equation of motion of the analytical model, the frictional force changes in proportion to the displacement. The restoring-force is also proportional to the displacement. The restoring-force always works in the direction of the center. Therefore, the frictional force and the restoring-force are both proportional to the displacement. Simulation analysis was performed under various conditions using this analysis model. As a result of conducting the analysis and an experiment with this model, it was shown that response acceleration and relative displacement can be reduced successfully. In order to reduce response acceleration and relative displacement more, analysis was carried out with the actual earthquake waves under the conditions to change the coefficient of friction by relative displacement. As a result, the coefficient of friction that reduces relative displacement most effectively without impairing the performance of the seismic isolator was established. However, the coefficient of friction that reduces the response acceleration and relative displacement effectively depends on by seismic waves. Therefore, in this report, the coefficient of friction that reduces response acceleration and relative displacement most effectively is determined by using white noise. It is analyzed with actual seismic waves by using the decided parameters. The performance of the seismic isolator is examined.

MICRO-SLIP INDUCED DAMPING IN THE CONTACT OF NOMINALLY FLAT SURFACES

2013 ◽  
Vol 05 (01) ◽  
pp. 1350005 ◽  
Author(s):  
NOUSSA BOUCHAALA ◽  
JEAN LUC DION ◽  
NICOLAS PEYRET ◽  
MOHAMED HADDAR
Keyword(s):  
Experimental Study ◽  
Energy Dissipation ◽  
Normal Load ◽  
Damping Ratio ◽  
Bolted Joints ◽  
Dissipated Energy ◽  
Statistical Distributions ◽  
Tangential Load ◽  
Flat Surfaces ◽  
The Coefficient Of Friction

It is well known that the friction between interfaces at bolted joints plays a major role in the damping of assembly structures. Friction can be either induced by macro-slipping or micro-slipping. The aim of this paper is to model and quantify the dissipated energy by micro-sliding down to the scale of roughness between two flat surfaces in order to compute the damping ratio. It was assumed that the coefficient of friction between two materials is constant and that friction is the only source of energy dissipation. An experimental study was conducted to measure static normal load and dynamic tangential load without any coupling between these two main directions. A rheological contact model based on the Extended Greenwood Model with micro-contacts and statistical distributions was developed and studied. Experimental results and simulations are compared in order to assess and discuss the model.

Application of stochastic fractal surface rupture on non-planar faults in tsunami simulation

2020 ◽  
Author(s):  
Shane Murphy ◽  
Andrè Herrero ◽  
Fabrizio Romano ◽  
Stefano Lorito
Keyword(s):  
Fault Plane ◽  
Velocity Model ◽  
Source Model ◽  
Tsunami Source ◽  
Surface Rupture ◽  
Tsunami Simulation ◽  
Model Complex ◽  
Source Models ◽  
Fault Trace ◽  
Subduction Zone Earthquakes

<p>Non-planar faults and surface reached rupture are seldom considered in the source modelling of subduction zone earthquakes. Here we present a new method for accounting for both phenomena in the generation of stochastic slip distribution while still maintaining self similar properties. To do this, we use the composite source model, which involves the placement of numerous circular dislocations on the fault plane. The fault plane is described by an unstructured mesh allowing for a non-planar surface while surface rupture is correctly accounted for by reflecting the slip from circular dislocations that intersect with the fault trace.</p><p>In a case study we demonstrate that the inclusion of rupture at the surface alters the ground or seafloor deformation both in terms of the magnitude (between 60%-20% in 5km zone near the fault trace) and the orientation of the deformation vectors (i.e. by up to 5 degrees). Such changes can have a significant effect on tsunami source and subsequent wave.</p><p>Additionally, with a prescribed rupture velocity model, complex source time functions can also be calculated for each element on the fault plane. Generally, rise time is assumed to be instantaneous in tsunami simulation.</p><p>We will also present preliminary results focused on comparing the tsunami wave height observed along nearby coastlines generated by the different source models (i.e. with/without surface reached rupture and variable source time functions).    </p>

Surface rupture and landscape response within the core of the great Mw 8.3 1934 earthquake mesoseismal area: the case of the Khutti Khola

2020 ◽  
Author(s):  
Magali Riesner ◽  
Laurent Bollinger ◽  
Magali Rizza ◽  
Yann Klinger ◽  
Soma Nath Sapkota ◽  
...  
Keyword(s):  
Potential Surface ◽  
Plate Boundary ◽  
Historical Earthquake ◽  
Surface Rupture ◽  
Alluvial Deposits ◽  
The Core ◽  
Landscape Response ◽  
Lateral Extent ◽  
Fault Trace ◽  
Colluvial Wedge

<p>Great earthquakes generated along the Himalayan mega-thrust plate boundary have been shown to rupture the surface. The Mw 8.3 1934 Bihar-Nepal earthquake is one of these major seismotectonic events. Previous studies focused on sites located at the western end of the fault trace concluded that the surface rupture associated with this earthquake is still locally preserved. Here we document a new site, along the Khutti Khola rivercut, in the core of the mesoseismal area. The effects of the earthquake in that area were described as cataclysmic, generating massive damages, landslides blocking one of the local rivers at 4 sites. The Khutti river cuts the frontal range, incising a 4 m- high cumulated scarp exposed along a 19 m-long stretch of Siwaliks claystone-sandstone and alluvial deposits. A detailed study of the river cut revealed the presence of faults emplacing Siwaliks over quaternary alluvials. These units are sealed by a colluvial wedge and wash as well as by recent underformed alluvials. The C14 radiocarbon analyses of 10 detrital charcoals collected reveal that the last surface-rupturing event at that site occurred after the 17<sup>th</sup> century and prior to the post-bomb deposition of the young alluvials. The only historical earthquake known within that period is the 1934 earthquake, inferring that for this event the rupture reached the surface at that site. The rupture was followed by rapid aggradation and sealed by ~2 meters of sediments. In addition to being another rare example for the preservation of the 1934 earthquake, these observations demonstrate that, despite their magnitude and potential surface rupture, the study of the great Himalayan paleo-earthquakes are still challenging however necessary to constrain their lateral extent.</p>

Multicontact Solid Friction: A Macroscopic Probe of Pinning and Dissipation on the Mesoscopic Scale

MRS Bulletin ◽  
1998 ◽  
Vol 23 (6) ◽  
pp. 41-46 ◽  
Author(s):  
Tristan Baumberger ◽  
Christiane Caroli
Keyword(s):  
Normal Load ◽  
Theoretical Work ◽  
Mesoscopic Scale ◽  
Low Velocity ◽  
Local Pressure ◽  
Static State ◽  
The Real ◽  
Flat Surfaces ◽  
The Coefficient Of Friction ◽  
Image Position

In this article, we review the present status of experimental and theoretical work on friction at the interface between extended macroscopic bodies, rough on the micrometer scale. We show that systematic detailed studies of low-velocity friction using dynamical systems analysis, together with their shear response in the static state, provide a tool for investigating the physical processes taking place on the mesoscopic scale of real contacts between rough surfaces. This approach should shed light on the enduring question of the relationship between macroscopic friction and microscopic dissipative mechanisms. This still open issue has come back to the fore during the last decades, following considerable progress due to the development of “molecular tribometers.Bowden and Tabor pointed out that, because nominally flat surfaces are in general rough on small scales, the real area of contact Ar (Figure 1) is only a small fraction ϕ of apparent contact area A0. On the other hand, they postulated the existence of a stressσs characteristic of the shear strength of the interface between a given couple of solids. Hence the friction force:In this framework, the Amontons-Coulomb (AC) law F = μFN amounts to stating that Ar is proportional to the normal load FN where μ is the coefficient of friction.When considering soft metals, Bowden and Tabor noticed that ϕ ≪ 1 entails that the nominal local pressure p on the real contacts—of the order of FN/(ϕA0)–generally overcomes the yield strength Y so that the contacting asperities flow plastically until p = H≈ 3Y, the “hardness” of the (softer) material. So, Ar = FN/H.

scholarly journals Mud Volcanoes

2021 ◽  
pp. 323-342
Author(s):  
Chi-Yuen Wang ◽  
Michael Manga
Keyword(s):  
Seismic Waves ◽  
Mud Volcanoes ◽  
Dynamic Stresses ◽  
Permeability Changes ◽  
Triggering Mechanisms ◽  
Multiparameter Monitoring ◽  
Mud Flow

AbstractThe eruption of mud and magma can be influenced by earthquakes and reports date back more than 2000 years. Dozens of examples of eruptions have now been documented in response to both static and dynamic stresses from earthquakes. Already erupting systems are most sensitive to earthquakes compared to initiating new eruptions. Multiple plausible mechanisms have been proposed for triggering eruptions including disrupting particle-rich materials, mobilizing bubbles, or changing permeability—changes may occur both within and outside the reservoir hosting the materials that ultimately erupt. Using historical examples of triggered mud eruptions, we explain why it is unlikely that the Sidoarjo mud flow (sometimes nicknamed “Lusi”) was initiated by an earthquake. As multiparameter monitoring of volcanoes expands, it may eventually be possible to identify triggering mechanisms and how seismic waves influence magma and mud mobility in field settings.

Application of a Simple Cold Stub to the Direct Observation of Frozen Hydrated Sand

1973 ◽  
Vol 31 ◽  
pp. 212-213
Author(s):  
John M. Wehrung ◽  
Richard J. Harniman
Keyword(s):  
United States ◽  
Surface Water ◽  
Direct Observation ◽  
Controlled Study ◽  
Clay Particles ◽  
Organic Debris ◽  
Rock Formations ◽  
Water Tables ◽  
Permeable Rock ◽  
Natural Means

Water tables in aquifer regions of the southwest United States are dropping off at a rate which is greater than can be replaced by natural means. It is estimated that by 1985 wells will run dry in this region unless adequate artificial recharging can be accomplished. Recharging with surface water is limited by the plugging of permeable rock formations underground by clay particles and organic debris.A controlled study was initiated in which sand grains were used as the rock formation and water with known clay concentrations as the recharge media. The plugging mechanism was investigated by direct observation in the SEM of frozen hydrated sand samples from selected depths.

HREM observation of dislocations near room temperature fractures in silicon

1988 ◽  
Vol 46 ◽  
pp. 892-893
Author(s):  
M. H. Rhee ◽  
W. A. Coghlan
Keyword(s):  
Cross Section ◽  
Room Temperature ◽  
Single Crystal Silicon ◽  
Dislocation Nucleation ◽  
Back Side ◽  
Ion Milling ◽  
Crystal Silicon ◽  
Flat Surfaces ◽  
Induced Fractures ◽  
Vicker’S Microhardness

Silicon is believed to be an almost perfectly brittle material with cleavage occurring on {111} planes. In such a material at room temperature cleavage is expected to occur prior to any dislocation nucleation. This behavior suggests that cleavage fracture may be used to produce usable flat surfaces. Attempts to show this have failed. Such fractures produced in semiconductor silicon tend to occur on planes of variable orientation resulting in surfaces with a poor surface finish. In order to learn more about the mechanisms involved in fracture of silicon we began a HREM study of hardness indent induced fractures in thin samples of oxidized silicon.Samples of single crystal silicon were oxidized in air for 100 hours at 1000°C. Two pieces of this material were glued together and 500 μm thick cross-section samples were cut from the combined piece. The cross-section samples were indented using a Vicker's microhardness tester to produce cracks. The cracks in the samples were preserved by thinning from the back side using a combination of mechanical grinding and ion milling.

A TEM study of electron tunneling in biological macromolecules

1987 ◽  
Vol 45 ◽  
pp. 140-141
Author(s):  
J. A. Panitz
Keyword(s):  
Stark Effect ◽  
Electron Tunneling ◽  
Imaging Modality ◽  
Tunneling Current ◽  
Biological Species ◽  
Scanning Tunneling ◽  
Biological Macromolecules ◽  
Flat Surfaces ◽  
Virus Particles ◽  
Stm Images

Tunneling is a ubiquitous phenomenon. Alpha particle disintegration, the Stark effect, superconductivity in thin films, field-emission, and field-ionization are examples of electron tunneling phenomena. In the scanning tunneling microscope (STM) electron tunneling is used as an imaging modality. STM images of flat surfaces show structure at the atomic level. However, STM images of large biological species deposited onto flat surfaces are disappointing. For example, unstained virus particles imaged in the STM do not resemble their TEM counterparts.It is not clear how an STM image of a biological species is formed. Most biological species are large compared to the nominal electrode separation of ∼ 1nm that is required for electron tunneling. To form an image of a biological species, the tunneling electrodes must be separated by a distance that would normally be too large for a tunneling current to be observed.

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