Methodology for Full Waveform Near Real-Time Automatic Detection and Localization of Microseismic Events Using High (8 kHz) Sampling Rate Records in Mines: Application to the Garpenberg Mine (Sweden)

2019 ◽  
Vol 91 (1) ◽  
pp. 399-414 ◽  
Author(s):  
Kadek Hendrawan Palgunadi ◽  
Natalia Poiata ◽  
Jannes Kinscher ◽  
Pascal Bernard ◽  
Francesca De Santis ◽  
...  
Keyword(s):  
Real Time ◽  
Sampling Rate ◽  
Seismic Network ◽  
Event Extraction ◽  
Noise Sources ◽  
Full Waveform ◽  
High Sampling ◽  
High Sampling Rate ◽  
Wide Range ◽  
Microseismic Events

Abstract Recent studies have demonstrated the success of automatic full-waveform detection and location methods in analyzing and monitoring natural and induced seismicity. These approaches have been shown to provide a significant improvement in events detectability, increasing the significance of statistical analysis that permits to identify small changes of seismicity rates in space and time. Although currently nontrivial and by far nonstandard, application of such methods to seismic monitoring of active mines could significantly improve forecasting of potential destructive rockburst events. The main challenges of such applications are related to the presence of a wide range of seismic noise sources that have to do with mining activity and a high sampling rate of recorded data (several kHz), posing problems for real-time data transfer and processing. In this study, we propose an adapted full-waveform-based automatic method for the detection and location of microseismic events that makes use of continuous seismic records from an in-mine seismic network and can be adjusted to a near-real-time monitoring scheme. The method consists of two steps: (1) event extraction and amplitude ratio-based preliminary location and (2) event relocation using a coherency-based backprojection approach. The event extraction, based on multiband signal characterization implemented in the first step, allows us to overcome the challenge of high sampling rate data (8 kHz), reducing the overall volume of transferred data and providing an energy-based signal classification scheme. This allows us to remove a significant number of machinery noise sources. The technique is developed and tested on the case study of the Garpenberg mine (Sweden) monitored by a local seismic network that is maintained by Ineris. We demonstrate the improvement in event detection capacity by a factor of 50, compared with the standard triggered-based monitoring schemes. This increased number of detected microseismic events permits us to investigate the migration pattern of induced microseismicity that is generated in response to production blast.

Micro-seismicity of the Northern Sea of Galilee - Before and During the July-August 2018 Seismic Swarm

2020 ◽  
Author(s):  
Ittai Kurzon
Keyword(s):  
Seismic Activity ◽  
Time Windows ◽  
Sampling Rate ◽  
Seismic Network ◽  
Seismic Stations ◽  
Seismic Swarm ◽  
The North ◽  
Seismic Catalogue ◽  
High Sampling ◽  
High Sampling Rate

<p>This study presents observations and analysis from a high-sampling-rate micro-seismic network, located at the north of the Sea of Galilee, Israel. Stations’ locations were chosen following the seismic swarm at the North of the Sea of Galilee, in October 2013, aiming to perceive a better understanding of the seismicity and structure of this area, in light of that anomaly seismic swarm, and of the seismic activity along the Dead Sea Fault. The micro-seismic network was active between May 2016 to August 2018, with six stations altogether, in distances of 3-5km around the northern Sea of Galilee.  Each of the micro-seismic stations had two collocated sensors: 1) GS-1 Geospace, 1 Hz vertical seismometers, sampled at 500 samples per second, and 2) 3-channel Episensor embedded in a Rock+ Kinemetrics datalogger, sampled at 200 samples per second. Towards the dismantling of the network, another swarm, stronger in magnitude, and longer in duration, has occurred in July-August 2018, roughly at the same location. Meanwhile, a significant upgrade of the Israel Seismic Network (ISN) was taking place, also densifying the number of stations around the Sea of Galilee.</p><p>The seismic processing presented here has many steps of verification, at all levels: detection, association, and location.  Processing begins with the local high-sampling-rate micro-seismic stations, tuning the most appropriate micro-seismic detectors, and association, location and magnitude parameters. Then this new generated micro-seismic catalogue is used to reveal lower magnitude events within the ISN stations, followed by relocation and re-magnitude estimations, done to those events that have additional information from the ISN stations. Running this process for increasing time-windows, it is demonstrated how the use of micro-seismic instrumentation can increase the seismic catalogue by an order of magnitude, providing higher resolution of the seismicity, both in space and time.</p><p>These efforts, of increasing the seismic catalogue, and improving their locations, are utilised for two main goals: a) obtaining a clearer picture of the seismicity and structure in the area before and during the seismic swarm of July-August 2018, b) Zooming into the interesting micro-seismic activity just before the initiation of the swarm.</p>

Intelligent Displacement Measuring System for Rock Stratum

2011 ◽  
Vol 103 ◽  
pp. 583-586
Author(s):  
Feng Ling Li ◽  
Jian Hua Rong ◽  
Yu Ping Zhang
Keyword(s):  
Civil Engineer ◽  
Real Time ◽  
Sampling Rate ◽  
Measuring System ◽  
Displacement Sensor ◽  
Rock Stratum ◽  
Baud Rate ◽  
Real Time Clock ◽  
High Sampling Rate ◽  
Displacement System

Measuring rock stratum displacement in dam grouting process is very important. A new displacement system is designed, comprising a programmable microcontroller Atmega16, a new grating capacitive displacement sensor(GCDS), DS1302 real time clock chip and announciator etc. The system has high sampling rate of 9600 baud rate and can trap the displacement equal to 0.001 millimeter in one second. Equipped with mechanical conveyance system, the system can be applied to the civil engineer. The experiment results show the instrument can measure accurately the displacement value and alarm geologic disaster in time, which can conduct continuous and accurate monitoring and provide operation decisions for dam engineers.

All-optical parallelization for high sampling rate photonic ADC in fully digital radar systems

2010 ◽  
Author(s):  
Paolo Ghelfi ◽  
Lingmei Ma ◽  
Xiaoxia Wu ◽  
Minyu Yao ◽  
Alan E. Willner ◽  
...  
Keyword(s):  
Sampling Rate ◽  
Radar Systems ◽  
High Sampling ◽  
High Sampling Rate ◽  
All Optical

scholarly journals High sampling rate thermistor string observations at the slope of Great Meteor Seamount

Ocean Science ◽  
2005 ◽  
Vol 1 (1) ◽  
pp. 17-28 ◽  
Author(s):  
H. van Haren ◽  
R. Groenewegen ◽  
M. Laan ◽  
B. Koster
Keyword(s):  
High Frequency ◽  
North Atlantic Ocean ◽  
Sampling Rate ◽  
Very High Frequency ◽  
High Sampling ◽  
High Sampling Rate ◽  
In Situ Calibration ◽  
Great Meteor Seamount ◽  
Very High

Abstract. A high sampling rate (1 Hz) thermistor string has been built to accommodate the scientific need to accurately monitor high-frequency and vigorous internal wave and overturning processes in the ocean. The thermistors and their custom designed electronics can register temperature at an estimated precision of about 0.001° C with a response time faster than 0.25 s down to depths of 6000 m. With a quick in situ calibration using SBE 911 CTD an absolute accuracy of 0.005° C is obtained. The present string holds 128 sensors at 0.5 m intervals, which are all read-out within 0.5 s. When sampling at 1 Hz, the batteries and the memory capacity of the recorder allow for deployments of up to 2 weeks. In this paper, the instrument is described in some detail. Its performance is illustrated with examples from the first moored observations, which show Kelvin-Helmholtz overturning and very high-frequency (Doppler-shifted) internal waves besides occasionally large turbulent bores moving up the sloping side of Great Meteor Seamount, Canary Basin, North-Atlantic Ocean.

Torsional Vibration Detection Using High Sampling Rate and High Resolution Keyphasor Information

2013 ◽  
Author(s):  
Huageng Luo ◽  
Roengchai Chumai ◽  
Nicolas Peton ◽  
Brian Howard ◽  
Arun Menon
Keyword(s):  
Torsional Vibration ◽  
Sampling Rate ◽  
Synchronous Motor ◽  
Rotating Machinery ◽  
Normal Operation ◽  
Machinery Condition Monitoring ◽  
Vibration Detection ◽  
High Sampling ◽  
High Sampling Rate ◽  
Phase Demodulation

Torsional vibration excitation in rotating machinery can cause system reliability issues or even catastrophic failures. Torsional vibration detection and monitoring becomes an important step in rotating machinery condition monitoring, especially for those machines driven by a variable frequency drive (VFD), a pulse width modulation motor (PWM), or a synchronous motor (SM), etc. Traditionally, the torsional vibration is detected by a phase demodulation process applied to the signals generated by tooth wheels or optical encoders. This demodulation based method has a few unfavorable issues: the installation of the tooth wheels needs to interrupt the machinery normal operation; the installation of the optical barcode is relatively easier, however, it suffers from short term survivability in harsh industrial environments. The geometric irregularities in the tooth wheel and the end discontinuity in the optical encoder will sometimes introduce overwhelming contaminations from shaft order response and its harmonics. In addition, the Hilbert Transform based phase demodulation technique has inevitable errors caused by the edge effect in FFT and IFFT analyses. Fortunately, in many industrial rotating machinery applications, the torsional vibration resonant frequency is usually low and the Keyphasor® and/or encoder for speed monitoring is readily available. Thus, it is feasible to use existing hardware for torsional vibration detection. In this paper, we present a signal processing approach which used the Keyphasor/encoder data digitized by a high sampling rate and high digitization resolution analog-to-digital (A/D) convertor to evaluate the torsional vibration directly. A wavelet decomposition (WD) based method was used to separate the torsional vibration from the shaft speed, so that the time history of the torsional vibrations can be extracted without significant distortions. The developed approach was then validated through a synchronous motor fan drive and an industrial power generation system. Detailed results are presented and discussed in this paper.

High sampling rate or high resolution in a sub-Nyquist sampling system

Measurement ◽  
2020 ◽  
Vol 166 ◽  
pp. 108175
Author(s):  
Yijiu Zhao ◽  
Houjun Wang ◽  
Yanze Zheng ◽  
Yi Zhuang ◽  
Naixin Zhou
Keyword(s):  
High Resolution ◽  
Sampling Rate ◽  
Sampling System ◽  
High Sampling ◽  
High Sampling Rate
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