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Geode Frequently Asked Questions (FAQ):
1. What is a Geode?
A Geode is a small waterproof and shock-proof seismic recorder. Each Geode contains circuitry to measure the signals from geophones placed in the ground. Geodes are situated close to the geophones out on the ground. Geophones are usually measuring acoustic energy returning to the surface. The acoustic energy is caused by a hammer blow, an explosion, a weight drop or a vibrating mass.
2. How is a Geode different from a conventional seismic recorder?
Conventional seismographs usually have a control computer and the measurement circuitry packaged together in a single container. They connect to geophones using long spread cables which can be heavy and costly. Conventional seismic recorders are not very weatherproof, so they are typically covered or housed in a vehicle for protection from the elements.
Geodes, on the other hand, are completely sealed and are deployed very close to the geophones out in the field. Geodes are physically close to the geophones so short cables can be used to attach to them. Geodes transmit their data back to a central location using light, inexpensive digital cable.
3. How do I control a Geode?
Almost any PC running Windows 98/NT/ME/W2K or XP will do, including your laptop. The computer will need a network card (standard on most devices these days). PCMCIA network cards are widely available and work well for laptops, which make very suitable field devices. If you are using the laptop outside, pick one with a bright display that you can see in the sun. 128 Mb of memory or greater will improve performance.
4. How many channels will a Geode hold?
Geodes house from 3 to 24 Geodes in a small, 9 lb (4 kg) box. You can connect Geodes together to make systems up to 1000 channels.
5. What kinds of surveys can I use a Geode for?
You can use a Geode for any survey that you use a conventional system for – reflection, refraction, downhold, VSP, checkshot or cross hole tomography. The Geode's wide bandwidth and extremely long record lengths allow any kind of vibratory or pseudo-random source (Mini-Sosie) to be used. Self-triggering and special pretrigger memory facilitate earthquake monitoring as well as vibration and blast measurements.
6. Can I connect Geodes together to build larger systems?
Yes, you can connect many Geodes together and build systems up to 1000 channels.
7. What is a Geode distributed system?
The term "distributed" refers to method in which the circuitry to measure the geophones (A/D converters) is deployed. In older, conventional seismic recorders, all of the A/D circuitry is housed in one place, often in a vehicle, at one central location. This means that heavy and expensive analog cables are used to transmit the tiny geophone signals back to the central location, often decreasing signal levels as the spread cables cross power lines, pipes or act as antennae. In a distributed configuration, small, sealed boxes containing the A/D measurement circuitry are placed close to the geophones right on the ground. The signals from the geophones are digitized close to their source and data can be transferred back to a small computer using noiseless digital cables. This means lighter, cheaper cables, better data quality and a lighter, more portable system.
8. What software do I need to run a Geode.
Geodes are available with two different versions of operating software – SGOS and MGOS. SGOS stands for "Single Geode Operating System and is used to control a single Geode module of up to 24 channels. If you were doing small engineering surveys, this is what you would probably uses.
MGOS stands for Multiple Geode OperatingSystem and has additional networking software to manage many Geodes on many lines. There are also some additional features like a real-time spectral window, a roll function, multiple preamp gains that make MGOS more suitable for larger scale surveys.
9. Why would I use a Geode system instead of a conventional seismograph?
- Portability
- Expandability and flexibility
- Decouples the PC from the system
- Longer life
Why would I want to use a conventional seismograph instead of a Geode system?
- Everything in one place
- For small systems less than 24 channels there may be no significant functional advantage to a distributed system. A Geode might be cheaper though.
- Built-in, very rugged PC
- Daylight visible screen (most laptops are poor in the sun).
- I already own conventional cables
- I need a built in printer
10. Can I have both a conventional and a distributed seismic system using Geodes?
The architecture of the Geode and StrataVisor NZ product allows you to have both a conventional and distributed system together (see the StrataView NZ data sheet). The StrataVisor NZ seismograph can contain up to 64 internal channels (128 channels rack mounted) and additional network cards can be added to operate additional external Geodes.
You might choose this mixed configuration if you already own analog spread cables and do small surveys with them, but occasionally wish to expand up to larger systems of 120 channel or more.
- You can also purchase an NZC, which is an NZ with no channels. The NZC is shorter, but contains four built-in lines to control Geodes. It is very rugged. This combination provides perhaps the best of both worlds.
11. What is the standard separation between Geodes?
Geodes can transmit up to 0.25km (250 m) between modules. Repeaters are available to go further, or any Geode can be programmed to be a repeater.
12. Can I place Geodes further apart?
Yes, Geodes can be also used as repeaters so you can go up to 1.5 km between boxes. It is possible to go further than this, but a trigger repeater would be required.
13. Can you tell me the maximum practical distances between geophones for various Geode configurations?
- A single Geode with 3 to 24 channels has no distance limitation between geophones, since there is only one analog spread cable.
- Two Geodes, each with 3 to 24 channel each have no distance limitation between geophones, since they can be situated beside each other with the spread cables pointed in opposite directions.
- Three or more colinear Geodes (all in a line) can be separated by a maximum of 250 m (unless you are using repeaters). If you require 30m between geophones, each Geode should be configured with 8 channels per box. If 10m between geophones are required, up to 24 channels per Geode is acceptable. Channels in the Geode can be turned offor on via the control software to accomplish these configurations, or A/D cards simply removed from the boxes.
14. What applications software comes with a Geode?
- ·SIPTQC refraction software based on Rimrock Geophysic's widely used SIPT software. SIPQC runs directly on your laptop and can be launched from within MGOS or SGOS software. This software is also available in a PC version.
- SeisImager refraction software from Geometrics. This versatile software includes a modeling package, a first break picker, and three methods of interpreting data. Click here to download a SeisImager data sheet. Go to the DOWNLOADS page for more information and a trial version of SeisImager.
- WinSeis-Lite, a full featured reflection package for processing CDP style reflection data
15. Can I plug my Geode into any other Geometrics seismograph?
You can plug your seismograph into a StrataVisor NZ. Older Geometrics seismographs are not compatible.
16. What kind of cable is used to send digital signals between Geodes?
Geometrics uses standard, lightweight CAT5 Ethernet cable, widely available anywhere in the world. We also have CAT5 cable with an extruded coating for operation in harsh environments. This covering is required for cold weather operation.
17. Can I build Geode digital cables myself?
Yes. We use General Connector U77/U connectors. You can download a wiring diagram here. Use Beldon 1752A cable. Instruction assembly diagram is available here. This cable can be coated for use in harsh environments. Contact Geometrics.
18. Can I use my old 12 channel refraction cables with NK-27 connectors with a Geode?
Yes, we can provide an adapter cable.
19. How does the optional self-trigger algorithm on the Geode work?Click here to download a technical data sheet on self-triggering
20. How do I power the Geode(s)? Are they efficient?
Geodes are powered from a small 12V external battery. A motorcycle battery (10 AH) will operate the system all day.
21. What grade of electronic components are used in Geode contruction.
Geodes use entirely industrial and military grade electronic components to achieve the –30 to 75C temperature extremes and the shock and vibration tolerances that we advertise in our specifications. Other manufacturers use commercial grade components as they are less expensive, but less reliable.
22. How are Geode boards tested.
Each Geode board is subjected to full temperature range testing (specs are proven at –30, +75 and at room temperature) for every system shipped. The Geode was designed to be dropped from 1m onto concrete and withstands the MIL810E vibration standard.
23. Are Geodes waterproof?
Geodes are completely sealed and do not need to be opened. All connectors and the test switch conform to IP67 or IP68 ratings. Our tests show Geodese can be submerged for up to an hour at .25m water depth or up to 1 m for 10 minutes. However, there is a breather valve on the front of the Geode to allow access if there is a vaccuum inside. This must be closed before submersion, so please be careful. Each Geode includes a dessicant pack to remove moisture.
24. Are Geodes shock proof?
Geodes have undergone rigorous testing at our own test facilities and at outside testing labs that we hire. All boards in the Geode are cushioned with rubber shock mounts. We have dropped Geodes from 1 m unto concrete on 14 points (all sides and corners). Geodes have been shaken to 18g at transportation frequencies and pass the MIL810E vibration transportation tests. Whereas we don't recommend you take these extremes with your Geodes, you can rest assured we have exposed them to shock and vibration that far exceeds most field use, to ensure reliability.
25. What software components are available as options?
- marine surveying
- sub-bottom profiling
- continuous acquisition, 100% recording with no missed samples. May limit the number of channels or sample rates available as A/D cards can collect data faster than it can be transferred to the PC
- blast monitoring
- mini-sosie, pseudo-random source processing
Please contact us at Geometrics if you would like to discuss any of these applications, or new applications that would require custom software.Please download our software options data sheet for more details.
26. What is meant by a "field version" of the processing software like SeisImager or SIPQC refraction software.
Field versions of software operate only when the ES-3000 or Geode is connected and operating from your laptop. This applies also to the NZ seismograph.
27. Can I use an USB Ethernet adapter to run the Geode?
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