Portable Seismic Stations

Portable Seismic Stations

Portable Seismic Stations

GEObit provides compact solutions for quick deploy seismic stations based on GEOThree digitizer/recorder and C100 sensor. The GEOThree recorder has 3 input channels, and integrated sensor electronics. The digitizer is based on a powerful, wide dynamic range 32bit delta-sigma analog-to-digital converter, with very low noise characteristics and excellent power supply rejection. The sampling rate can be set to 50, 100, 200, 250, 500 and 1000 samples per second. The sensor response is 10sec – 98Hz. The data are stored into removable microSD card. Ultra low power consumption allows over one month of operation if getting powered from an ordinary 12V/65Ah lead-acid battery.

The LCD, displays the State-of-Health, time and date and other information related to the instrument’s operation. The digitizer is intended for installation in harsh environments. The instrument supports embedded SEEDlink server for real time data telemetry.

Applications

  • Aftershock studies
  • Local and regional seismicity monitoring
  • Seismic Tomography
  • Reservoir monitoring
  • Induced seismicity monitoring
  •  Geothermal monitoring
  • Structural monitoring (Dams, Bridges, Ancient Castles)

Here we present the instrumentation which have been used in several passive tomography projects as well as several micro-seismicity and induced seismicity projects, and explain why we propose the use of this kind of equipment.

Micro-Seismicity Monitoring Instrumentation GEOThree Compact Sensor/Digitizer/Recorder Unit

Figure 1: seismic Event

So why chose a GEObit unit? 

1. Why wide band sensor?

At micro-seismicity monitoring experiments and applications the seismic events usually have a magnitude from –2R, up to 4R, and their frequency spectrum is into the band 0.8Hz to 20Hz. So, a wide band seismometer with the range of at least 0.5Hz(2 sec) up to 30 Hz is necessary to be used for the recording of such seismic events. In micro-seismicity monitoring , we are using sensors with recording bandwidth from 0.1Hz to 100Hz in order to record the seismic events with the maximum quality. The low frequency response gives us the ability to calculate moment tensors as well.

Figure 2: seismic Event plot

Figure 3: seismic event spectrum plot

Somebody may ask, why not broadband sensors? The answer is that the broadband sensors are much more expensive than our sensors and makes the survey inefficient in price terms. We do not get more information using broad-band sensors of local micro-earthquakes recording. At the next experiment we used wide band and broad-band sensors at the seismic network. Here is an example of a recorded earthquake.

Figure 4: seismic event recorded from wide-band and broad band sensors

Figure 5: seismic event spectrum of the broad-band sensor

Figure 6: seismic event spectrum of the wide-band sensor

The figure 4 shows a typical seismic event recorded from a wide-band and eight broad-band (Nanometrics – Trillium 40T) sensors. Trace 19 is the broad-band one and it could not be recognized from others having a first look at the signal plot. The frequency spectrum of the BB sensor and the spectrum of the wide-band sensors are presented at figures 5 and 6 respectively. These spectrum plots represent frequencies of the recorded signals of the same earthquake. Clearly, both are equal, therefore enev with the use of wide-band sensor, the recording result is equal.

Why not using simple geophones? Commercial geophones with small dimensions have usually natural frequency 4.5Hz or 10Hz. Using these kind of geophones, the lower part of the spectrum of the signal is lost (low frequency), because the geophones cannot respond in the low frequency area (below 4.5 Hz), and its sensitivity falls dramatically. There are also geophones in the market with natural frequency of 2.0Hz or 2.5Hz, but their dimensions do not allow to be used in small boreholes. Their bandwidth is quite enough for magnitude 1 or 2 local events, but not enough to cover low frequency, below 1Hz.

2. Why force-balance sensor?

The S-100 sensor is based on force-balance principle. Special electronics provide feedback at 4.5Hz geophones, plus additional electronic bandwidth correction and provide a 10sec-98Hz sensor unit. The 4.5Hz geophones are not so sensiitive over tilt. Usually they respond perfectly within 5 – 10 degrees of tilt. This means that the sensor can be installed into the borehole without any need of special leveling. An elastic packer provided from us, is more than enough to hold the sensor into the borehole. It is leveled according the casing verticality and it is operational, ranging within its characteristics even there is some degrees of tilt at the borehole casing. So, the ideal solution for fast, accurate installation is the wide-band seismometers consisted of 4.5Hz geophones, having small dimensions and low cost, designed according the force-balance principle. Our wide-band sensors meet all the requirements for local micro-earthquake recording in the passive tomography projects and in our new GEOThree digitizer/recorder, the sensor electronics are build-in into the instrument.

3. Why borehole type sensor?

Many seismic sensors are surface mount type. For their installation, usually seismic vaults have to be opened, where the noise level is less than the surface. Our instruments are mostly borehole type, so they can be easily installed in a typical depth 20 meters. The noise level at this depth is much less than the surface. The borehole can easily be (in the most of the cases) opened using a drilling machine at low cost, within some working hours. Small diameter boreholes can be opened by hand in rough areas where no vehicles can access.

Figure 7: seismic noise at 20m depth borehole

Figure 8: seismic noise at the surface

Figure 9: Sinusoidial signal for sensor calibration

Figure 10: Pulse signal for sensor calibration

4. Why high sensitivity sensor?

 The magnitude (Richter Scale) of the recorded events for the passive seismic tomography exploration, range from –2R to 3R. For the recording of such small events, the sensor must be very sensitive. Our instruments provide high sensitivity such as 1500V/m/sec.

5. Why in-build sensor self test?

 The operator needs a way to apply a fast signal test to the equipment in order to verify proper operation. Most of the clients are asking for such kind of tests to be performed from the instruments by themselves. The GEOThree recorder provides a build-in signal generator combined with a micro-controller, and injects signal to the sensor. The square wave or sinusoidal signal that injected to the sensor with constant amplitude, forces the masses of the geophones to move. The geophones produce a seismic signal to their output proportional to their movement. The shape of this signal that the user should see is shown at the figures 9 and 10.

Once the user connects  with the GEOThree unit through the DataMonitor, he can verify the proper operation of the sensor. In parallel, the processor of the digitizer uses this signal to perform auto-calibration function at the system. So, all the seismic stations of the microseismic network can always be calibrated during the recording period.

6. Why high resolution digitiser?

 The resolution of the digitiser is one of the most important parameters of the seismic instrumentation. 24bits digitizers are mostly used in seismic exploration. The GEOThree unit is based on a 4rd generation 32bit digitizer, with dynamic range 136dB at 250sps, while dynamic range is 142dB at 10sps.

7. Why big capacity storage media?

Our standalone seismic stations units are getting powered from a typical 12V battery which may be cycler from seismic crew or charged by a solar panel. The seismic crew usually visits the stations once per month or later for changing battery and retrieving the data. For places that this routine visit is difficult to be done, because that the access of some stations is difficult, the storage media must have enough capacity to store the data for longer period. Using a 2Gb microSD the recording duration for 3ch, 100sps will be up to 26days. Larger capacity Compact Flash Card will be used for larger recording period. The units support up to 64Gbytes flash card.

Figure 11: Digitizer noise spectrum

Figure 12: Digitizer noise histogram plot

Figure 13: Portable seismic station 

8. Why very low power consumption?

 One other important point of the standalone seismic station is the power autonomy. Given that is it powered from a simple 12V lead acid battery, the cycle must be as many days as the seismic crew needs to visit the seismic station. Seismic networks consisted of 50 seismic stations, spread in an area of 1000 – 2000 Sqm2 placed in accessible terrain, usually takes a few weeks to the seismic crew for visiting them. So the power autonomy of each seismic station (recorder + sensor) must be enough for at least one month of operation. Our seismic stations can operate for this time period, powered from a set of double 12V/62Ah lead –acid batteriy.

AGU Fall Meeting 2022: We are back

AGU Fall Meeting 2022: We are back

Geobit & ISTI join together at the AGU Fall Meeting in Chicago, IL, 12 – 16 Dec 2022.

We are glad to announce that we are exhibiting live again at the AGU Fall Meeting, after an absence of two years, because of Covid19 restrictions.

With 65+ years of combined experience, GEObit and ISTI are joining forces to become the most competitive and fastest growing joint venture group in the seismic monitoring services industry.

Providing state-of-the-art seismic instruments, network design, installation techniques, data monitoring and processing services, our group is able to deliver a cost-effective total solution to the energy exploration & production industry, especially to the oil, gas and geothermal sector. Our key benefits are that we produce in-house hardware and software while installing and maintaining the microseismic monitoring network to ensure a high level of data quality and availability. In other words, we make the technology – we apply the technology – we offer the technology.

We have worldwide experience having installed and operated seismic networks all over the world, from Indonesia/Papua jungle to the Middle East desert, from Alaska glaciers to Himalayan Mountains. In the USA, we are currently running many dedicated microseismic monitoring projects with over 200 stations installed in the past 10 years.

Visit us at booth #1726, AGU 2022

 

Chicago, IL, USA  |  12 – 16 December

 

Meet our team and learn about the latest offerings. Dimitris Mourtzouchos & Effie Siaini (Geobit), Paul Friberg & Sid Hellman (ISTI), and others will be available to answer your questions.

McCormick Place - South Building

2301 S King Dr, Chicago, IL 60616

More information about AGU Fall Meeting 2019 may be found here.

The Thailand roadshow

The Thailand roadshow

Seismic Instruments for Active Faults Monitoring, Engineering Seismology and Earthquake Early Warning

Geobit and World Tech Enterprise Ltd present an exclusive geophysics lecture event, Seismic Instruments for Active Faults Monitoring, Engineering Seismology and Earthquake Early Warning in Bangkok, Thailand.

In this seminar, earthquake monitoring tools will be presented for proactive faults detection, as well as engineering science and monitoring to advance earthquake warnings, to be helpful in coping when situations occur and preparing for the future of Thailand.

The event will take place at Ibis Style Hotel Bangkok Ratchada, Bangkok, Thailand on Tuesday 13 December 2022, 09:00 local time.

Registrations are free and can be done here.

Geobit is exhibiting at The Earthquake Expo Asia

Geobit is exhibiting at The Earthquake Expo Asia

Natural Disasters Expo Asia 2022

We are pleased to announce that Geobit is exhibiting at the Earthquake Expo Asia 2022, part of the Natural Disasters Expo Asia 2022. We welcome you to visit our booth, to meet our team and learn about our new upcoming instruments and technologies. We will also be available to answer your questions.

The exhibition is being held 7–8 December 2022 at Singapore Expo, Hall 3, 1 Expo Drive, Singapore 486150.

Opening Times:

Wednesday, 7th December 2022
10am – 5pm

Thursday, 8th December 2022
10am – 4pm

We hope to see you there!

When: 7 - 8 December 2022

Where: Singapore Expo, Hall 3, 1 Expo Drive, Singapore, 486150

Natural Disaster Expo is segmented into 4 zones: Flood, Earthquake, Heat & Fire and Storm, bringing visitor focus to the most costly natural disasters in the world. It is a destination for disaster preparedness experts and emergency responce professionals to discover the newest disaster-related products, services and advancements in order to maximize recovery methods and increase the efficiency of community outreach.

Geobit to discuss with future resellers and distributors

After years of cooperation with advanced geophysical companies in limited areas of Asia, we are now open to discuss the expansion of our network.

If you are interested in becoming a Geobit reseller or Distributor, we are welcome you in our booth #916 to discuss details and opportunities.

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Multi-Channel Systems

Multi-Channel Systems

Multi-Channel Systems for Structural Monitoring applications

  • Multi-channel systems (up to 1000 recording channels) with parallel data recording at the central recording unit
  • Parallel data processing
  • Usage of 32bit ADC digitizer units
  • Extremely low power consumption, only 0.2W per channel
  • Real time telemetry over seedlink protocol & system control
  • Variety selection of analog sensors (BB seismometer, Short Period Seismometer, Geophone Force-Balance, High Frequency Geophone, Deep Borehole Geophone Sensor, Water Pressure, Hydrophone, Seismic Accelerometer, Strong Motion Accelerometer, MEMS Accelerometer)
  • Real time data processing module according to the DIN4150 format
  • Real time user alert

GEObit provides a flexible, real time, immediate warning structural monitoring solution. We combine our GEOThree digitizers/recorders and a very powerful processing unit for providing real time structural motoring & alert system.

The Geobit advanced multi-channel structural monitoring system supports real time automatic user alert. The system acquires data from all the channels at 200sps per channel by default, continuously and processes them in real time. The vibration level is calculated in DIN4150 format and if the level exceeds the standard limit, the user receives alert sms and e-mail.

The multi channel system has been used as well in several applications requiring real time vibrations monitoring, like blast monitoring, structure vibrations monitoring caused from nearby works or constructions, or ancient buildings monitoring by any type of human source vibrations.

The GEOShock software

The communication and analysis software (GEOShock) is running on a linux pc, with the following features: Signal waveform plot, FFT analysis, spectrum response, energy content per frequency, file conversion in ASCII format, individual trigger level set of each sensor, alert via e-mail or sms when SPPV exceeds predefined limits etc. The software can be installed into any computer and thus the user can receive data in real time and have them processed in multiple receiving points. The software includes the data plot software “SeisGram2k” and the SPPV monitor.

The implementation of the software has been developed in a such way that it provides continuous monitoring and recording of the vibrations in real time and in parallel vibration calculation at every minute and how many times the SPPV limit has been exceeded (if so). The SPPV limit is not constant but linear to the frequency from 10 to 100Hz and can be derived from the structural study of the building.

The software has the ability to send automated email notifications to the user in case of exceeding the limits.

The SPPV velocity calculation is automatically performed from the monitor service program GEOshock that processes the data in real time, calculates the SPPV magnitude and displays it in a plot as function of frequency. It also plots the maximum SPPV value that is calculated every  minute.  If the SPPV threshold is exceeded, the user receives an alert e-mail containing the maximum value that exceed the threshold.

Geobit sponsored the 16th Congress of Geological Society of Greece

Geobit sponsored the 16th Congress of Geological Society of Greece

16th International Congress of the Geological Society of Greece

We are pleased to announce that Geobit is exhibiting and sponsoring as Gold Sponsor, the 16th International Congress of the Geological Society of Greece 2022. We welcome you to visit our booth, to meet our team and learn about our new upcoming instruments and technologies. We will also be available to answer your questions.

The Congress of the Geological Society of Greece is being held 17–19 September 2022 in Patras, Greece.

We hope to see you there!

When: 17 - 19 October 2022

Where: Conference & Cultural Center of the University of Patras, Patras, Greece

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