Tilts in Strong Ground Motion

Graizer, Vladimir

doi:10.1785/0120060065

Cited by 152 publications

(85 citation statements)

References 27 publications

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“…Whilst tilt 'contamination' of the vertical 326 component is generally considered minimal (Graizer, 2006), recorded horizontal (e and n) 327 acceleration (and hence velocity and displacement) can be overestimated unless corrected for 328 (Young et al, 2012). The effects of ground tilt on horizontal displacement increase with 329 increasing period (Webb and Crawford, 1999;Crawford and Webb, 2000) but have been 330…”

Section: Fatigue Damage Accumulation Zones 244mentioning

confidence: 99%

Are microseismic ground displacements a significant geomorphic agent?

et al. 2014

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Abstract 5 This paper considers the role that microseismic ground displacements may play in fracturing 6 rock via cyclic loading and subcritical crack growth. Using a coastal rock cliff as a case 7 study, we firstly undertake a literature review to define the spatial locations that may be prone 8 to microseismic damage. It is suggested that microseismic weakening of rock can only occur 9 in 'damage accumulation zones' of limited spatial extent. Stress concentrations resulting from 10 cliff height, slope angle and surface morphology may nucleate and propagate a sufficiently 11 dense population of microcracks that can then be exploited by microseismic cyclic loading. 12We subsequently examine a 32-day microseismic dataset obtained from a coastal cliff-top 13 location at Staithes, UK. The dataset demonstrates that microseismic ground displacements 14 display low peak amplitudes that are punctuated by periods of greater displacement during 15 storm conditions. Microseismic displacements generally display limited preferential 16 directivity, though we observe rarely occurring sustained ground motions with a cliff-normal 17 component during storm events. High magnitude displacements and infrequently experienced 18 ground motion directions may be more damaging than the more frequently occurring, 19 reduced magnitude displacements characteristic of periods of relative quiescence. As high 20 magnitude, low frequency events exceed and then increase the damage threshold, these 21 extremes may also render intervening, reduced magnitude microseismic displacements 22 ineffective in terms of damage accumulation as a result of crack tip blunting and the 23 2 generation of residual compressive stresses that close microcracks. We contend that damage 24 resulting from microseismic ground motion may be episodic, rather than being continuous 25 and in (quasi-)proportional and cumulative response to environmental forcing. A conceptual 26 model is proposed that describes when and where microseismic ground motions can operate 27 effectively. We hypothesise that there are significant spatial and temporal limitations on 28 effective microseismic damage accumulation, such that the net efficacy of microseismic 29 ground motions in preparing rock for fracture, and hence in enhancing erosion, may be 30 considerably lower than previously suggested in locations where high magnitude 31 displacements punctuate 'standard' displacement conditions. Determining and measuring the 32 exact effects of microseismic ground disp...

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Section: Fatigue Damage Accumulation Zones 244mentioning

confidence: 99%

Are microseismic ground displacements a significant geomorphic agent?

et al. 2014

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“…Therefore, the original shaking record has to be corrected so as to avoid the wavy nature of the displacement waveform. The baseline shift may be attributed to many reasons including ground tilting [11], and contamination of low-frequency noise. Baseline correction is found to be effective in removing low-frequency content and it is actually a method of high-pass filtering with an unknown cut-off frequency [1].…”

Section: Data Acquisition Processing and Analysismentioning

confidence: 99%

Systematic Approaches for Signal Processing of Soil Shaking Table Test

2017

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Abstract.Selecting an appropriate methodology in signal processing of shaking table test is of fundamental importance for evaluating the soil dynamic parameters. This paper presents the systematic approaches in selecting an appropriate signal processing method for a soil shaking table test. A soil model of 150 mm in diameter and 100 mm in height was tested on a 1g shaking table. The soil model was instrumented with accelerometers to measure the resultant accelerations under different shaking motions. Under normal data processing practices, the acceleration data was adjusted and numerically integrated to obtain the linear displacement data. However, the accuracy and reliability of the computed displacement data and the adopted adjustment technique often raise arguments. In the present study, the acceleration data was subjected to two baseline correction schemes and one method of digital band-pass filtering. The results from the three signal processing methods were compared with the actual displacement data obtained from a direct measurement using laser displacement sensor. Bandpass filtering method was found to be a more reliable data processing method in this particular study. The use of laser displacement sensor can serve as a useful reference when choosing an appropriate adjustment scheme in data processing.

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“…Strong motion (SM) data, which is inexpensive, can provide high-frequency information with high precision and high sensitivity; however, the integrated velocity and displacement are seriously distorted owing to a baseline shift caused by low-frequency noise and tilting or rotation of the instrument; consequently, the recovered displacement has a precision of the order of decimeters or worse [9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Integration of Single-Frequency GNSS and Strong-Motion Observations for Real-Time Earthquake Monitoring

Zhang

et al. 2018

Remote Sensing

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Abstract:In this study, a real-time earthquake monitoring system based on the integration of single-frequency global navigation satellite system (GNSS) and strong motion (SM) observations was developed. This high-precision integrated system can provide full-frequency monitoring information, and it makes full use of SM data to quickly and accurately determine the vibration window for initial baseline shift correction. High-precision displacement data obtained from GNSS epoch-differenced velocity estimation are used to constrain the SM's low-frequency baseline shift. Hence, full-frequency monitoring information (displacement, velocity, and acceleration) can be provided in real-time. Three different datasets were used for validation and the results confirm that the proposed system can be used for practical earthquake monitoring.

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Tilts in Strong Ground Motion

Cited by 152 publications

References 27 publications

Are microseismic ground displacements a significant geomorphic agent?

Are microseismic ground displacements a significant geomorphic agent?

Systematic Approaches for Signal Processing of Soil Shaking Table Test

Integration of Single-Frequency GNSS and Strong-Motion Observations for Real-Time Earthquake Monitoring

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