Predictability of strong motions from the Northridge, California, earthquake

Abstract The composite source model for generating synthetic strong ground motions is tested for its ability to predict the statistical characteristics of Northridge accelerograms recorded in or adjacent to the San Fernando valley. The general problem is prediction of strong motions at a site of engineering interest with sufficient realism to be useful for engineering applications. The strongest test of any proposed method is a blind prediction. For this study, a completely blind test was not possible. Our objective was to use only a preliminary description of fault geometry and magnitude and previously published velocity models and, without iteration to improve the quality of fit, to evaluate the differences between predicted and observed accelerograms. The parameters that we predict are peak acceleration, peak velocity, peak displacement, Fourier spectra at seven frequencies, and pseudorelative velocity response (5% damping) at seven periods. Our results are given for 14 stations. For the horizontal components, these parameters are all predicted with a maximum bias of under 50% and an average bias of observations exceeding predictions by 6%. For peak acceleration and some response spectral periods, the bias for this model is smaller than at least some regressions, when applied to this specific earthquake. On the vertical component, the maximum bias is a factor of 2, and the average gives predictions exceeding observations by 25%. Standard deviations of the common logarithm of the ratio of observed-to-predicted parameters are typically about 0.3, which is perhaps 50% greater than the standard deviations typical of regressions but comparable to standard deviations of observations from this earthquake compared to regressions. In the future, it is likely that, in some cases, traditional regressions will be replaced with synthetic calculations of some type, such as the method used here. Based on the results of this study, the amount of progress that has been made in obtaining that goal is very encouraging.

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Blind Test of Methods for Obtaining Velocity Models from First‐Arrival Travel Times Using Refraction Tomography Methods

10.4133/1.3614075 ◽

2011 ◽

Author(s):

Julian Ivanov ◽

Richard Miller ◽

Shelby Peterie

Keyword(s):

Travel Times ◽

Blind Test ◽

Velocity Models ◽

Refraction Tomography ◽

First Arrival Travel Times ◽

First Arrival

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Preliminary Results of Receiver Function Forward Velocity Modelling at Merapi Volcano

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/873/1/012056 ◽

2021 ◽

Vol 873 (1) ◽

pp. 012056

Author(s):

M F R Auly ◽

A K Ilahi ◽

I Madrinovella ◽

S Widyanti ◽

S K Suhardja ◽

...

Keyword(s):

Receiver Function ◽

Tectonic Setting ◽

Vertical Component ◽

P Wave ◽

Function Technique ◽

Boundary Current ◽

Low Velocity ◽

Mantle Boundary ◽

Velocity Models ◽

Synthetic Model

Abstract The tectonic setting of Java island, located at southwestern edge of the Eurasia continent, is dominated by the subduction of Indo-Australia plate. One of the characteristics of active subduction is active seismicity, the generation of arc magmatism and volcanic activity. Mt. Merapi is one example of active volcano related with the subduction process. It is one of the most active volcanoes with location close to high population area. To better understand this area, we employed the Receiver Function technique, a method to image sub surface structure by removing the vertical component from horizontal component. First, we collected high magnitude events and processed RF with water level deconvolution method. Then, we constructed synthetic model with initial velocity input from previous tomography model. Note that we used reflectivity method in generating synthetic model with input parameters matched with parameters from real data processing. Next, we adjusted velocity inputs mainly on tops sediments (1-3 km) to include sediment layers and volcanic rocks, mid-depth low velocity zone that may be related with magma chamber and depth of crust-mantle boundary. Current forward velocity models show a relatively good agreement from 3 stations (ME25, ME32 and ME36). We estimate a thin layer of sediments followed a zone of velocity layer at a depth of 10-15 km and crust-mantle boundary ranging from 26-29 km. In this study, simulated that the signal of sediments layer and low velocity layers interfere main crust mantle boundary that supposed to be highest signal after the P wave in the typical receiver function study.

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RETRACTED ARTICLE: Estimation of the source process and forward simulation of long-period ground motion of the 2018 Hokkaido Eastern Iburi, Japan, earthquake

Earth Planets and Space ◽

10.1186/s40623-019-1079-6 ◽

2019 ◽

Vol 71 (1) ◽

Cited By ~ 1

Author(s):

Hisahiko Kubo ◽

Asako Iwaki ◽

Wataru Suzuki ◽

Shin Aoi ◽

Haruko Sekiguchi

Keyword(s):

Ground Motion ◽

Velocity Structure ◽

Time Window ◽

Waveform Inversion ◽

Strong Motion ◽

Source Model ◽

Multiple Time ◽

Velocity Models ◽

Long Period ◽

Slip Area

Abstract In this study, we investigate the source rupture process of the 2018 Hokkaido Eastern Iburi earthquake in Japan (MJMA 6.7) and how the ground motion can be reproduced using available source and velocity models. First, we conduct a multiple-time-window kinematic waveform inversion using strong-motion waveforms, which indicates that a large-slip area located at a depth of 25–30 km in the up-dip direction from the hypocenter was caused by a rupture propagating upward 6–12 s after its initiation. Moreover, the high-seismicity area of aftershocks did not overlap with the large-slip area. Subsequently, using the obtained source model and a three-dimensional velocity structure model, we conduct a forward long-period (< 0.5 Hz) ground-motion simulation. The simulation was able to reproduce the overall ground-motion characteristics in the sedimentary layers of the Ishikari Lowland.

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Effects of Whole-Body Vibration in Hematobiochemical and Hemogasometric Parameters in Adult and Elderly Healthy Dogs

Acta Scientiae Veterinariae ◽

10.22456/1679-9216.105418 ◽

2020 ◽

Vol 48 ◽

Author(s):

Bruna Martins Silva ◽

Ivan Felismino Charas Santos ◽

Sheila Canevese Rahal ◽

Carmel Dadalto ◽

Lais Rosa Nagai ◽

...

Keyword(s):

Alanine Aminotransferase ◽

Mechanical Vibration ◽

Whole Body Vibration ◽

Whole Body ◽

Peak Acceleration ◽

Single Session ◽

Peak Displacement ◽

Body Vibration ◽

Vibrating Platform ◽

Healthy Dogs

Background: Whole-Body Vibration (WBV) consists of mechanical vibration stimuli produced that propagate throughout the body by increasing the gravitational load. The WBV can increase muscle mass in dogs with muscular atrophy. As Whole-body vibration (WBV) can be used as exercise modality with no impact on the joints, the present study aimed to evaluate the effects of single session of WBV in hematobiochemical and hemogasometric parameters in adult and elderly healthy dogs. Materials, Methods & Results: Fourteen clinically healthy, neutered crossbreed male dogs, non-athlete were selected. The dogs were divided into two groups of seven dogs, according to the age group: Group I - adult dogs (GI): age between 12.0 and 84.0 months old; Group II - elderly dogs (GII): age above 84.0 months old. All dogs were submitted to a single session WBV by using a vibrating platform that delivered a vortex wave circulation as mechanical vibration. The WBV protocol used was 30 Hz frequency (3.10 mm peak displacement; 11.16 m/s2 peak acceleration; 0.29 m/s velocity), then 50 Hz (3.98 mm peak displacement; 39.75 m/s2 peak acceleration; 0.62 m/s velocity), and lastly 30 Hz (3.10 mm peak displacement; 11.16 m/s2 peak acceleration; 0.29 m/s velocity) for 5-min between de frequencies. The hematobiochemical and hemagasometric parameters were evaluated at 1-min before the WBV session (1PRE), 1-min after the WBV session (1POST), 120-min (120POST) and 24 hours after the WBV session (24hPOST). The dogs accepted well the vibration stimulus, however, elderly dogs weighting above 30 kg were more likely to sit down with increased frequency from 30 to 50 Hz. No variations of food and water intakes and gastrointestinal changes were observed after the WBV session. Hemoglobin values showed significant decrease (P = 0.0312) between 1PRE and 1POST in elderly dogs. A significant decrease (P = 0.0453) was observed in alanine aminotransferase values between 120POST and 14hPOST in adult dogs. Creatinine values had a statically decrease (P = 0.0173) between 1PRE and 24hPOST in adult dogs. However, these values remained within the reference range for dogs. Discussion: According to the literature, there are no studies related to the effects of WBV in haematobiochemical and hemogasometric parameters in adult and elderly dogs. No deleterious effects regarding to a single session of WBV were observed, however harmful effects were observed in human patients. The elderly dogs with body mass above 30 kg tried to sit during the increased frequency from 30 to 50 Hz, which was associated with the pressure exerted in their paws. No significant differences were observed in erythrogram and leukogram parameters except for hemoglobin values. Significant decline was observed in hemoglobin values in adult Beagle dogs; and were associated with hemolysis. The significant decrease in alanine aminotransferase and creatinine values did not have clinical significance. No significant alterations were identified in hemogasometric parameters but slight increase in pH values was observed in horses subjected to a 60 km run, and was associated to the loss of Cl ions in sweat. The single session of WBV by using a vibrating platform that delivered a vortex wave circulation, at 30 and 50 Hz frequencies for 5 min did not induced significant changes in hematobiochemical and hemogasometric parameters in adults and elderly healthy dogs.

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Determination of Vegetal Proteins in Milk Powder by Enzyme-Linked Immunosorbent Assay: Interlaboratory Study

Journal of AOAC International ◽

10.1093/jaoac/85.6.1390 ◽

2002 ◽

Vol 85 (6) ◽

pp. 1390-1397 ◽

Cited By ~ 20

Author(s):

Lourdes Sánchez ◽

María D Pérez ◽

Pilar Puyol ◽

Miguel Calvo ◽

Gary Brett ◽

...

Keyword(s):

Immunosorbent Assay ◽

Polyclonal Antibodies ◽

Collaborative Study ◽

Milk Powder ◽

Enzyme Linked Immunosorbent Assay ◽

Wheat Proteins ◽

Blind Test ◽

Relative Standard ◽

Standard Deviations ◽

Phosphate Buffered Saline

Abstract Eight laboratories participated in a collaborative study to evaluate an enzyme-linked immunosorbent assay (ELISA) to determine soy, pea, and wheat proteins in pasteurized or ultra-high temperature (UHT) milk powders. To perform this assay, polyclonal antibodies for soy, pea, and wheat proteins were obtained from rabbit sera. Collaborators received calibration standards composed of milk powder containing 0–8% (w/w) vegetal protein in total protein and blind test samples containing approximately 1, 2, and 5% (w/w) vegetal protein. An indirect competitive ELISA was performed with a kit prepared by a participating laboratory; the kit contained plates coated with soy, pea, or wheat proteins, the corresponding specific antisera, enzyme-labeled second antibody, and substrate solution. Test samples and calibrants were extracted with phosphate-buffered saline, pH 7.4, containing 0.05% Tween and assayed with the ELISA kits. The degree of adulteration was affected by the type of heat treatment applied to the samples. The estimated percentage of vegetal protein addition was close to the theoretical value for pasteurized samples but much lower for UHT samples. For pasteurized samples, intralaboratory relative standard deviations ranged from 5 to 22% and interlaboratory relative standard deviations ranged from 14 to 34%.

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A workflow to discern 1D and 2D ground resonances with single-station microtremor measurements

10.5194/egusphere-egu21-3430 ◽

2021 ◽

Author(s):

Giulia Sgattoni ◽

Silvia Castellaro

Keyword(s):

Site Response ◽

Vertical Component ◽

Sediment Layer ◽

Resonance Frequencies ◽

Single Station ◽

Spectral Components ◽

Bedrock Depth ◽

A Site ◽

Microtremor Measurements ◽

Three Components

Measuring ground resonances is of great importance for seismic site amplification studies. The task is usually addressed with the common H/V (horizontal to vertical spectral ratio) approach, which is widely used for both microzonation studies and stratigraphic imaging. Peaks on the H/V function are used to identify ground resonance frequencies, usually assuming 1D site conditions, i.e. with plane-parallel stratigraphy. In the simple case of a horizontal soft layer overlying a bedrock, 1D resonance is linked to the local bedrock depth (as a function of the shear wave velocity of the sediment layer). Therefore, when the 1D approximation holds, spatial variations of the resonance frequency reflect changes of bedrock depth (when lateral homogeneity of the sediment cover can be assumed). However, at sites with non-plane subsurface geometries, more complex resonance patterns may develop, such as 2D resonance patterns that typically occur within sediment-filled valleys. In this case, 2D resonance involves simultaneous vibration of the whole sedimentary infill at the same frequency, which may lead to large seismic amplification. 2D ground resonances can no longer be linked to the local depth-to-bedrock directly below the measurement site, but depend on the whole valley geometry and mechanic properties. Distinguishing between the 1D and 2D nature of a site is mandatory to avoid wrong stratigraphic and dynamic interpretations, which is in turn extremely relevant for seismic site response assessment.We investigated the problem in the Bolzano sedimentary basin (Northern Italy), which lies at the intersection between three valleys, using a single-station microtremor approach, the same usually applied for H/V surveys. We observed that the footprints of 1D and 2D resonances reside in different behaviors along the three components of motion. This is because, while the dynamic behavior of a 1D-site is the same along all horizontal directions, 2D resonances differ along the longitudinal and transversal directions of the resonating body, e.g. parallel and perpendicular to the valley axis. In addition, 2D resonance modes involve also a vertical component. This implies that the H/V method, by mixing the information along the three components, is not suitable to detect 2D resonances, that can be acknowledged only by looking at the individual spectral components and not at the H/V curves alone.By analyzing several hundred single-station microtremor measurements, we identified a list of frequency and amplitude features that characterize 1D and 2D resonances on individual spectral components of motion and on H/V ratios, on a single measurement and on several measurements acquired along profiles across the investigated valleys. We identified valleys characterized by 1D-only, 1D+2D and 2D-only resonance patterns and we propose a workflow scheme to conduct experimental measurements and data analysis in order to directly assess the 1D or 2D resonance nature of a site with a single-station approach, rather than evaluating this indirectly with numerical modelling.

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Worklife Expectancies of Railroad Workers Based on the Twenty-Seventh Actuarial Valuation Using Competing Risks/Multiple Decrement Theory and the Markov Railroad Model

Journal of Forensic Economics ◽

10.5085/jfe-472 ◽

2020 ◽

Author(s):

James E. Ciecka ◽

Gary R. Skoog

Keyword(s):

Competing Risks ◽

Web Site ◽

Weighted Average ◽

Statistical Characteristics ◽

Accurate Calculation ◽

Railroad Workers ◽

Forensic Economics ◽

Standard Deviations ◽

Years Of Service

Abstract This paper contains worklife expectancies (WLE) of railroad workers based on the Twenty-Seventh Actuarial Valuation (Bureau of the Actuary, 2018), thereby updating the previous study of railroad workers' WLE based on the Twenty-Fifth Actuarial Valuation (Bureau of the Actuary, 2012). The main results of this paper are shown in a set of tables.11The tables in this paper provide worklife expectancies and standard deviations for every five years of service and five years of age and are referred to as abridged tables. Readers may interpolate as appropriate—e.g., a 23-year-old railroader would have a 60%/40% weighted average between the age 25 and age 20 entries. In addition, a more accurate calculation is available. The Association of American Railroads has requested that we provide it with complete unabridged tables that may be distributed to its members and posted on its web site. We have done so under a contract with the Association of American Railroads, which provides that those unabridged tables may be posted on the Journal of Forensic Economics web site. They appear there as supplemental materials to this paper, along with other supplemental content which includes Excel worksheets and additional statistical characteristics.

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Electrical detection of leaks in lined waste disposal ponds

Geophysics ◽

10.1190/1.1444274 ◽

1997 ◽

Vol 62 (6) ◽

pp. 1737-1744 ◽

Cited By ~ 15

Author(s):

William Frangos

Keyword(s):

Waste Disposal ◽

Current Source ◽

Nonlinear Inversion ◽

Blind Test ◽

Location Accuracy ◽

Electrical Potentials ◽

Practical Concern ◽

Plastic Liner ◽

A Site ◽

Processing Steps

A method for detecting and locating leaks in the plastic liner of a waste disposal pond has been implemented and tested at a site near Budmerice in Slovakia. The method is based on detecting electric current flowing through holes in the insulating lining membrane. Unlike similar methods employed elsewhere, this implementation allows monitoring for leaks that may develop during and after filling the pond with electrically inhomogeneous solid waste. To accomplish this goal, sensing electrodes were placed below the membrane during construction. In operation, current was passed between an electrode inside the pond and another outside; the voltage caused by this current was observed on the buried sensing electrodes. The data were then processed to detect and locate any leaks in the membrane. An important practical concern is achieving acceptable detectability and location accuracy while using a sufficiently sparse grid of sensing electrodes. This problem was overcome by two processing steps: (1) calculating electrical potentials from the observed voltages and (2) performing a nonlinear inversion on subsets of the data. With this technique, observations made with a 10- × 8-m grid of electrodes, a relatively low‐power current source, and a simple receiver can provide accurate location information, even for small leaks. In a blind test, the system accurately predicted the locations of six leaks that were subsequently verified visually. Five of the leaks were cuts in the plastic typically measuring less than 2 × 0.1 cm, whereas the sixth leak was a group of many small holes. For the five, the typical location accuracy was about 30 cm, comparable to the basic survey location accuracy of the sensing electrodes.

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