Geobit Instruments will not be affected by the “week number rollover” issue on 29th May 2021

Geobit Instruments will not be affected by the “week number rollover” issue on 29th May 2021

Geobit Instruments are not affected by the GPS week rollover issue.

We are pleased to inform you that all GEObit digitizers are using Garmin GPS receivers for time synchronization, and they will not be affected by the GPS rollover issue on 29th May 2021. As a result, all our digitizers will continue operating properly. No action needs to be taken by GEObit Instruments users.

At GEObit, we are always working to offer state-of-the-art technology and high-reliability products, requiring the minimum possible maintenance.

What is the GPS Week Number Rollover (WNRO)?

The GPS system is world renowned for its ability to provide accurate and reliable positioning and timing information worldwide. The GPS satellites transmit to users the date and time accurate to nanoseconds. However, back in 1980, when the GPS system first began to keep track of time, the date and time were represented by a counter that could only count forward to a maximum of 1024 weeks, or about 19.7 years. After 1024 weeks had elapsed, this counter “rolled over” to zero, and GPS time started counting forward again.  This first rollover occurred in August of 1999. The second rollover occurred on April 6, 2019. Several rollovers will happen in the future, depending on the manufacturer and the production date of the GPS receiver.

Is My Geobit Device Affected?

Our GPS supplier, Garmin, has anticipated and prepared for this event. Regardless, Garmin and Geobit have been performing exhaustive testing of current and legacy devices to determine if they will be affected by the GPS week number rollover.  Our testing shows the vast majority of Geobit devices will handle the WNRO without issues.

What is the Effect of a GPS Week Number Rollover Issue?

For GPS devices that are affected, after the rollover occurs, an incorrect date and time will be displayed. This incorrect time will also be used to timestamp track logs, compute sunrise and sunset, and other functions that rely upon the correct date and time. However, the positioning accuracy will not be affected. The device will continue to deliver the same positioning performance as before the rollover.

Geobit @ EUROVOLC 3rd Annual Meeting

Geobit @ EUROVOLC 3rd Annual Meeting

Geobit team in a previous Meeting

GEOBit will be available virtually at EUROVOLC Meeting

 

  • March 1st Presentation schedule:
    • Nikos Germenis – 15:35
  • Want to reach us outside of the above hours?

GEOtiny Compact Digital Seismometer

GEOfba200 Force Balance accelerometer

GEObit joins at the EUROVOLC 3rd Annual Meeting, 1 – 8 March 2021. 

We provide 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.

Nick Germenis (Geobit) will be a key speaker at the meeting

GEOThree Datalogger with C100 sensor

GEOtinyAC! Compact Digital Accelerograph

The Broadband Era

The Broadband Era

The arrival of the new year, 2021, marks the beginning of a new era in the history of Geobit. We are introducing the first Force Balance Accelerometer, the GEOfba200.

Currently, we are also working on the development of the Force Balance Accelerograph, which will be available in the market in the next couple of months.

Following our policy to provide low-cost quality instruments, the new FBA offered at a very competitive price. We implemented smart technologies, including AI techniques in order to produce a high technology instrument which will become a point of reference.

  • Low noise accelerometer for high precision and high dynamic range
  • Selectable full scale range +/-4g to +/-0.25g standard, higher gain set custom available
  • Wide passband DC to 215Hz, higher corner frequency custom available
  • Simple installation using a central fix bolt
  • Electronically adjustable DC offset
  • Power 9-18Vdc, 1.2W
  • Waterproof IP68 aluminum or stainless-steel casing

The GEOfba200 is a very low-noise triaxial force-balance accelerometer with a large dynamic range, suitable for seismology, hazard mitigation and civil engineering applications. The instrument has both a flat response to ground acceleration from DC to 215 Hz and a stable phase response within the passband. Output range is 40Vpp differentially and supports variety range of gain sets from +/-4g to +/-0.25g in the standard configuration and availability for higher gain set under request.

Due to it’s high dynamic range which exceeds 155dB the sensor provides from on-scale recording of earthquake motions to structural seismic noise monitoring and allows engineers to study motions at higher frequencies. The sensor allows easy field calibration through its calibration line.

GEOfba200 sensing element mechanism

Inside the GEOfba200 there are three similar accelerometers, orthogonally placed. The sensor is operating according to the force-balance principle as closed-loop sensor (servo accelerometer).

The motion of the seismic mass is monitored from a very sensitive capacitive transducer and a very low noise VHF preamplifier. The demodulator generates in-phase and low noise seismic signal which is fed back to the seismic mass through a phase compensator, a power amplifier and a fully symmetrical force actuator consisting of a double coil-magnet system. This design eliminates any non-linearity due to lack of symmetry. The output amplifier sets the selectable acceleration gain between +/-4g to +/-0.25g.

GEOfba200 block diagram

GEOfba200 self-noise

Red: 4g, Orange: 2g, Yellow 1g, Green 0.5g, Blue 0.25g

Geobit at AGU Fall Meeting 2020 as Virtual Supporter

Geobit at AGU Fall Meeting 2020 as Virtual Supporter

Geobit team in a previous AGU Fall Meeting

GEOBit & ISTI will be available virtually as AGU Supporters.

  • Meet and Greet :
    • Geobit staff 9am – 11pm EST, 7 – 11 Dec.
    • ISTI staff 11 – 6pm EST, 7 – 11 Dec.
    • Links to join each via Zoom TBA
  • Beer Hour:
    • Join us for a more casual meet and greet at the end of each day!
    • 6pm EST, 7 – 11 Dec.
    • Links to join via Zoom TBA
  • Stay tuned for:
    • what Geobit can do for you
    • and interesting extras we’ll be offering.
  • Want to reach us outside of the above hours?

GEOtiny Compact Digital Seismometer

GEObit & ISTI join together at the AGU 2020 Online Virtual meeting, 1 – 17 December 2020. We are a team providing a complete seismic monitoring solution.

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.

Nick Germenis (Geobit) and Sid Hellman (ISTI) in a previous AGU Fall Meeting

GEOThree Datalogger with C100 sensor

GEOtinyAC! Compact Digital Accelerograph

FREQUENTLY ASKED QUESTIONS ABOUT FALL MEETING 2020

As this will be the first virtual AGU Fall Meeting, the organizers issued some frequently asked questions in order to make our experience easier. Please read 

GENERAL

Where is Fall Meeting 2020 being held?
The Fall Meeting will be available in AGU online platform. They have partnered with various audio-visual providers to ensure quality streaming.

What are the dates for Fall Meeting 2020?
Fall Meeting 2020 will be held from 1-17 December.

Is the meeting still scheduled?
The AGU Fall Meeting will be one of the world’s largest virtual scientific conferences, with exciting programming and events. To assist in minimizing scheduling conflicts, #AGU20 is scheduled from 1-17 December, excluding weekends. Most content will be prerecorded or available as posters for attendees to view and peruse outside of scheduled sessions during the meeting.

When does the online registration tool open to register for the early bird fees?
Early registration will open in mid-September and close 30 October.

What is the expected meeting attendance?
Approximately 27,000 attended the meeting in 2019. View more statistics on the Fall Meeting.

Do I have to be an AGU member to attend?
No, but AGU members, and those who are members of cooperating societies, who joined or renewed their membership for 2020 by 30 October 2020, will receive reduced registration rates.

How do I become an AGU member?
Join AGU or renew your membership: online, via email, or by phone at +1202.462.6900.

SESSIONS, SCIENTIFIC WORKSHOPS, TOWN HALLS, OR EVENTS

Where can I view the full scientific program?

The scientific program is available here.

Where can I find a schedule at a glance?
The overall meeting schedule at a glance can be found here.

When will session chairs be notified of their session schedule?
Session Chairs received email notification of their session schedule on 5 October.

What is the the role of the session chair?
Session chair guidelines can be located here.

Why are sessions numbered differently this year?
Since the Fall Meeting is taking place 1-17 December, excluding weekends. sessions are not numbered as they normally are at a face-to-face meeting.

ABSTRACTS AND GUIDELINES

When will authors be notified of their session schedule?
Presenting and first authors received email notification of their session schedule on 5 October.

Where can I find presenter guidelines?
Oral, poster and eLightning presenter resources and guidelines can found here.

Where do I upload my oral presentation or poster?
Oral presenters please refer to the presentation guidelines and you may upload your pre-recorded presentation and overview slides (PDF) via the Participant’s Corner.
eLightning session presenters please refer to the guidelines for creating your virtual poster and login here to create your poster.
Poster presenters please refer to the guidelines for creating your virtual poster and login here to create your poster. 

eLIGHTNING

Where can I find presenter guidelines and resources?
eLightning presenter guidelines can found here.

Where do I upload my eLightning presentation?
eLightning session presenters please refer to the guidelines for creating your virtual poster and login here to create your poster. 

What if I don’t want to make my eLightning presentation permanently available in the library?

All eLightning presentations will be available for view in the Fall Meeting poster gallery. There will be an opt-out for any presenter who does not want their presentation to be available after the meeting. This library will be available to registered meeting attendees until mid-January. AGU is also investigating the various options for archiving eLightning presentations.

Is the eLightning library open access?
The virtual posters will be available to registered meeting attendees only.

Why is this named eLightning?
In 2016, AGU piloted a Lightning Poster Session format that allowed poster sessions to have a set time, outside of their designated time in the poster hall and in a separate room, for their presenters to give lightning presentations of their posters. This experiment was intended to encourage discussion, enable presenters in the same session to see each other present, and increase visibility of the posters. The current session format is built on the progress made and lessons learned from Lightning Poster Sessions, hence the Lightning in eLightning. We are adding additional value by providing more of an electronic ability, hence the e in eLightning. We also wanted to make sure that it wouldn’t be confused with our long-running ePoster program, where poster presenters are able to upload a static PDF copy of their poster to the online scientific program, so the word poster wasn’t included in the name.

TECHNOLOGY

Will you offer a mobile app this year?
No, there will not be a native application for Fall Meeting 2020.

HOTEL AND TRAVEL

How do I apply for a virtual student travel grant?
The online student travel grant application process opens in mid-June and closes in August. Learn more about the various grants offered to offset the costs of participating virtually.

When can I reserve my hotel room?
AGU will not provide housing for Fall Meeting 2020. If circumstances change and we are able to host a small regional meeting, we will provide an update via our various marketing platforms.

Does AGU offer travel discounts?
AGU will not offer any travel discounts for Fall Meeting 2020.

Visit Geobit @ 2020 SSA Annual Meeting

Visit Geobit @ 2020 SSA Annual Meeting

GEObit and ISTI are exhibiting at 2020 SSA Annual Meeting, 27–30 April, Albuquerque, New Mexico.

GEObit provides high sensitivity wide-band and near broad-band seismic sensors, surface or borehole type, and high dynamic range, low power 32bit ADC data loggers with local data storage and real-time telemetry over seedlink protocol. We are focusing on low power and cost-efficient solutions so we provide to our customer seismic networks with low installation and maintenance costs. Our instruments are ideal for local and regional seismicity and micro-seismicity monitoring and for seismic events such as those induced by unconventional hydrocarbon extraction. Our high fidelity data loggers ensure that these signals are recorded with the highest resolution and timing accuracy.

Together with ISTI, our USA & Canada representative, we welcome you to visit us at our booth, #12, to meet our team and learn about our new upcoming instruments and technologies. We will also be available to answer your questions.

More information about 2020 SSA Annual Meeting may be found here.

Wideband versus Broadband Seismic Sensors in Local and Regional Seismicity Monitoring

Wideband versus Broadband Seismic Sensors in Local and Regional Seismicity Monitoring

This poster was presented by N. Germenis at AGU Fall Meeting 2019, San Francisco, CA.

Abstract

As local earthquakes don’t produce very low frequencies, the use of expensive broadband seismometers, for local and regional seismicity monitoring, may be avoided. Low frequency geophones have been used in the past for this type of monitoring, however their response is typically very limited below 2Hz, and thus a magnitude overestimation may occur. In most cases, wide band seismic sensors are typically used in local and regional seismicity monitoring experiments, but it is not always clear what are the achievable measurement quality levels and how they compare to solutions that are more expensive.

This work tries to shed light into this problem, by presenting a comparative study among three widely available sensors, representing the state of the art in the market of both wideband and broadband sensors. Two different earthquake experiments have been used, with magnitudes ML 4.9 and 4.7 and epicenter distances of 200km and 100km, respectively. For each experiment, the waveform and spectrum plots of each vertical channel have been analyzed.

It is shown that, despite the complexity and cost differences, wideband sensors provide superior performance compared to broadband sensors in the range of their recording spectrum, with no loss of any low period information. Coupled with the cost differences, that allow more stations to be installed, the use of wideband sensors is the recommended way to go, for local and regional seismicity as well as micro-seismicity monitoring.

Figure 1. Seismometers in the seismic vault.

1. Experiment Setup

The scope of the experiment was the investigation of the performance of a wide band sensor (WB), in regional  and  local  earthquake  recording.  The  WB sensor was tested against a typical short period (SP) BB sensor while a Broad Band sensor (BB) was used as a reference. The seismic sensors were installed in a seismic vault, for a period of six months, and common WB recordings of local and regional events were extracted SP for analysis. The scope of the experiment was the investigation of the performance of a wide band sensor (WB), in regional  and  local  earthquake  recording.  The  WB sensor was tested against a typical short period (SP) BB sensor while a Broad Band sensor (BB) was used as a reference. The seismic sensors were installed in a seismic vault, for a period of six months, and common WB recordings of local and regional events were extracted SP for analysis.

Figure 2. Event A (left) and event B (right) records from the three instruments.

2. Waveform data

We have used waveform data from two regional events. The first one (Event A), was an ML 4.9 earthquake recorded at an epicentral distance of 200km, the second one (Event B) had a magnitude of ML 4.7 and was recorded at an epicentral distance of 100km. Instrumentally corrected records are plotted in Fig.2. Wide Band (WB) and Broad Band (BB) records are perfectly matched while the Short Period (SP) sensor clearly lacks longer periods, as expected.

Figure 3. Event A (left) and event B (right) records from the three instruments.

2. Results

In Fig.3 the Power Spectral Density plots of the two events, are presented. In both cases the WB and BB records have equal spectral characteristics, even in the low frequency band. As expected, the SP sensor cannot record accurately in the low frequency part.

References 

[1] Sokos, E. N., Zahradnik, J. ISOLA a Fortran code and a MatlabGUI to perform multiple-point source inversion of seismic data, Computers & Geosciences, Volume 34, Issue 8, August 2008, Pages 967-977.

[2] Sokos, E. and Zahradník, J. Evaluating Centroid‐Moment‐Tensor Uncertainty in the New Version of ISOLA Software, Seismological Research Letters, July/August 2013, v. 84, p. 656-665