A Real-Time Digital Seismic Event Detection and Recording System for Network Applications (original) (raw)
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A Computer-Aided Data Acquisition System for Multichannel Seismic Monitoring and Recording
IEEE Sensors Journal, 2016
This paper presents an innovative approach based on hardware and software to develop a multichannel seismic monitoring and data acquisition embedded system. The hardware was designed by using basic electronic components and integrated circuits. It consists of two parts, signal processing and microcontroller circuits. The signal processing circuit is a combination of preamplifier, low-pass filter, gain control, high-pass filter, dc offset, and clipper circuits. The proposed data acquisition system is able to record data at a sampling rate of 300 µs, with 10-bit resolution. It has three modes: real-time monitoring, continuous recording, and seismic refraction. The detected seismic signals were filtered using analog filters, which are low pass with 1 kHz and high pass with 2 Hz. A universal serial bus was utilized to communicate between the hardware and the personal computer. A graphical user interface based on windows operating system was developed using Microsoft.NET Framework for transferring, processing, and analyzing the data. The system was tested and experimental results showing the performance of the proposed system were presented. Earth scientists can use this system for educational seismic experiments. It can be easily modified and used for other engineering applications.
Data Automation for on-line Earthquake Precursory Signals
The paper presents the technical knowhow to build an automation software approach for monitoring, recording, and real time analysis of earthquake precursory signals. Three laboratories in different locations such as Bakreswar hot spring site, West Bengal, Baratang mud volcano site, Andaman & Nicobar Islands, and Tattapani hot spring site, Jammu & Kashmir have been developed so far to detect earthquake precursory signals. The various instruments in each of the laboratories include Alpha Guard radon monitor, Micro-gas chromatograph, Barasol radon monitor. All of these instruments are connected through a serial interface (RS-232) to the local server computer installed at each of the laboratories. Here we discuss in detail about the software algorithm in which automatic data acquisition from the connected instruments to the local server computer and automatic transmission of the stored data to the main server computer installed at NIT-Durgapur is done in real time. A web interface to the main server computer is also made. Using this web interface, a particular instrument of a particular laboratory can be selected. Time period (start date to end date) of the data to be accessed could be chosen and real time analysis of the data can be done.
Perspectives of Cross-Correlation in Seismic Monitoring at the International Data Centre
Pure and Applied Geophysics, 2014
We demonstrate that several techniques based on cross correlation are able to significantly reduce the detection threshold of seismic sources worldwide and to improve the reliability of IDC arrivals by a more accurate estimation of their defining parameters. More than ninety per cent of smaller REB events can be built in automatic processing while completely fitting the REB event definition criteria. The rate of false alarms, as compared to the events rejected from the SEL3 in the current interactive processing, has also been dramatically reduced by several powerful filters. The principal filter is the difference of arrival times between the master events and newly built events at three or more primary stations, which should lie in a narrow range of a few seconds. Two effective pre-filters are f-k analysis and F prob based on correlation traces instead of original waveforms. As a result, cross correlation may reduce the overall workload related to IDC interactive analysis and provide a precise tool for quality check for both arrivals and events.
Proceedings of the 6th International Conference on Sensor Networks, 2017
The rapid technological evolution in sensors, sensor platforms and networking is enabling the deployment of large sensor networks for "live" monitoring of seismic activity with high spatial resolution. In this regard, this paper describes our work in developing an online "High Throughput Seismic Sensor Network". We present the architecture and implementation comprising seismic sensors and servers (running data collection services) connected through internet-enabled technologies. We validate and assess the system, as well as identify bottlenecks, by means of experimentation. Based on the collected empirical data, we were able to identify methods and tools to support effective planning and implementation of sensor networks based on two main indicators: Sensor Network Transmission Rate (SNTR), which provides the overall network sensor data transmission throughput and thus an indication of the required network capacity; and CPU Sensor Network Performance Index (CSNPI), which provides an indication of a server capability to handle network sensor data. As we progress in our work to field deploy seismic sensor networks, we will continue to use these tools to plan and deploy future sensor networks, as well as assess improvements and modifications along the way.
A general earthquake-observation system (GEOS)
Microprocessor technology has permitted the development of a General Earthquake-Observation System (GEOS) useful for most seismic applications. Centralprocessing-unit control via robust software of system functions that are isolated on hardware modules permits field adaptability of the system to a wide variety of active and passive seismic experiments and straightforward modification for incorporation of improvements in technology. Various laboratory tests and numerous deployments of a set of the systems in the field have confirmed design goals, including: wide linear dynamic range (16 bit/96 dB); broad bandwidth (36 hr to 600 Hz; >36 hr available); selectable sensor-type (accelerometer, seismometer, dilatometer); selectable channels (1 to 6); selectable record mode (continuous, preset, trigger); large data capacity (1.4 to 60 Mbytes); selectable time standard (WWVB, master, manual); automatic self-calibration; simple field operation; full capability to adapt system in the field to a wide variety of experiments; low power; portability; and modest costs. System design goals for a microcomputer-controlled system with modular software and hardware components as implemented on the GEOS are presented. The systems have been deployed for 15 experiments, including: studies of near-source strong motion; high-frequency microearthquakes; crustal structure; down-hole wave propagation; teleseismicity; and earth-tidal strains. These studies have yielded recordings of near-source radiation fields in the frequency band of 1 to 300 Hz with signal resolution greater than 84 dB, documented seismic signals of 80 Hz at distances of 190 km with implications for nuclear detection, provided complete onscale high-resolution recording of several aftershock sequences with signal amplitudes ranging over 180 dB, and records of Earth dilational strain over the period band 0.1 sec to 28 hr, with superimosed radiation fields for nuclear explosions at regional distances and near-source earthquakes. Data sets recorded on the GEOS illustrate the importance of broad bandwidth, high resolution, and wide linear dynamic range for future earthquake studies. Field deployments of a minicomputer system compatible with the GEOS have emphasized the usefulness of portable field computers for experiments using microcomputer-controlled data-acquisition systems.
SAPS—An automated and networked seismological acquisition and processing system
Computers & Geosciences, 1996
A PC-based digital data acquisition and processing system was developed and implemented on two PCs linked by a peer-to-peer LAN. Sixteen channels are sampled with a rate of 200 Hz. The acquisition is performed continuously in sequenced files on one PC using the IASPEI-released XRTP software. The length of the elementary files is adjustable; we used 90sec in this application. The second PC runs a program to organize automatically the following processing steps: (i) moving the raw data from the first to the second PC: (ii) filterine. the data for running a 'Rex Allen'-like picker for P waves on each elementary file; (iii) concatenating three-consecutive element&y files if the detection criteria are fulfilled; (v) decoding a fast time code (Lennartz-style); (v) discriminating between Iocal and teleseismic events; (vi) plane-wave method location and mb determination for teleseisms; (vii) picking S waves, determining coda duration and locating local events; (viii) conversion of PC-SUDS into GSE format and 'feeding' a Data Request Manager with phases, locations and waveforms; (ix) sending phases and location, via e-mail, minutes after detection, and a 'health status' every hour, to the system manager; (x) plotting the raw data, the picks and printing the location results; and (xi) archiving data and results locally and on a remote workstation. The system has been running since April 1994 with data from the telemetered network of the Upper Rhinegraben. Being modular, the system can be extended and upgraded easily. Loss of data is avoided by using large hard disks as temporary data buffers and file mirroring on different hard disk drives.
Earthquake Early Warning Systems, 2007
In the framework of an ongoing project financed by the Campania Region, a prototype system for seismic early and post-event warning is being developed and tested, based on a dense, wide dynamic seismic network (IS-Net) and under installation in the Apennine belt region. This paper reports the characteristics of the seismic network, focussing on the required technological innovation of the different seismic network components (data-logger, sensors and data communication). To ensure a highly dynamic recording range, each station is equipped with two types of sensors: a strong-motion accelerometer and a velocimeter. Data acquisition at the seismic stations is performed using Osiris-6 model data-loggers made by Agecodagis. Each station is supplied with two (120 W) solar panels and two 130 Ah gel cell batteries, ensuring 72-h autonomy for the seismic and radio communication equipment. The site is also equipped with a GSM/GPRS programmable control/alarm system connected to several environmental sensors (door forcing, solar panel controller, battery, fire, etc) and through which the site status is known in real time. The data are stored locally on the hard-disk and, at the same time, continuously transmitted by the SeedLink protocol to local acquisi
Journal of scientific and industrial research
The paper highlights a new design approach to overcome technical limitations of digital seismographs by incorporating optimum hardware and efficient software modules etc. The paper illustrates how the new design approach has enhanced the limited 64 kbytes addressing capability of 8-bit microprocessor based seismograph to 16 Mbytes capacity. Instrument based on this design philosophy can now record many long duration seismic events and the series of subsequent aftershocks, which need storage of several mega bytes. The technique has enabled uninterrupted data acquisition and processing even when the data of earlier recorded events is being transferred from main storage to PC hard disk. The design concept has been validated successfully by operating the instrument based on this technique for long time in the field.