The Geometrics Geode is a popular engineering seismograph used by academics and geophysical professionals because of its ruggedness and versatility. The seismographs components are protected by a pelican case to prevent damage. It is powered by a deep cell 12 volt battery and connects to a laptop via Ethernet connection. The operating software must be installed on the laptop and can be found at the manufacturer’s website.
Typical uses for the Geode include reflection, refraction, MASW/MAM, or tomography surveys as well as for more niche use cases such as earthquake, quarry blasts, or heavy equipment monitoring. The geode can be used for marine profiling too. Geodes can be tethered together via Ethernet cable to expand the number of channels in increments of 24 for full scale 2D and 3D surveys.
Configurations and Considerations
The geode can be used with a variety of different spread cables and geophone types depending on which seismic methods and depths that the operator wants to reach. It is important that the operator verifies that the spread cable will plug either directly into the geode or connect via Y-adaptor cable.
In some situations, the operator may want to use more than the standard 24 channels. In this case, the user can tether together systems via the yellow Ethernet cable. Sometimes a rollbox may also be used to expand an array of geophones. When using a rollbox, only one geode is used.
Having a good 12v deep cycle battery is important to keep the geode powered. Always charge the deep cycle battery for a minimum of 24 hours before use. Batteries bought from the store are often discharged and do not last long unless charged first. An inverter may be needed to power any laptop that is running the operating software.
Geode Packing List
1 x Geode Seismograph Channels 24 S/N 4973
Customer Provides PC
1 x Power Cable
1 x External Ethernet Cable Assembly
1 x Network Interface Box
1 x Adapter Cable 2 by 12 to 24 for 12-Trace Spread Cables
1 x USB Flash Drive with Manuals and Software
2 x Spread Cable, 12 traces each
26 x Geophones (2 extra)
1 x Striker Plate
1 x Trigger Line 300 ft on Plastic Reel with hammer switch
2 x Shipping Totes (28x22x18, 55lbs, 70 lbs)
Configurations: 3, 6, 8, 12, 16 or 24 channels in weatherproof field deployable Geode module. Geode is operated from either 98/NT/2K/XP based laptop1 or by Geometrics’ ruggedized StrataVisor NZ field computer. Single Geodes are operated using SGOS software, which contains basic seismograph functions used for engineering surveys. Multiple Geodes can be connected together to build systems with many channels and many lines using MGOS software.
A/D Conversion: 24 bit result using Crystal Semiconductor sigma-delta converters and Geometrics proprietary over sampling.
Dynamic Range: 144 dB (system), 110 dB (instantaneous, measured) at 2 ms, 24 dB.
Distortion: 0.0005% @ 2 ms, 1.75 to 208 Hz.
Bandwidth: 1.75 Hz to 20 kHz. Low corner frequency option available.
Common Mode Rejection: > 100dB at <= 100 Hz, 36 dB.
Crosstalk: -125 dB at 23.5 Hz, 24 dB, 2 ms.
Noise Floor: 0.20 uV, RFI at 2 ms, 36 dB, 1.75 to 208 Hz.
Stacking Trigger Accuracy: 1/32 of sample interval.
Maximum Input Signal: 2.8V PP at 0dB
Input Impedance: 20 kOhm, 0.02 uf.
Preamplifier Gains: Software selectable between 24 and 36 dB. Can be jumpered to allow selection of 12 or 24 dB or jumpered to 0 dB.
Anti-alias Filters: -3 dB at 83% of Nyquist frequency, down 90 dB.
Acquisition and Display Filters:
Low Cut: OUT, 10, 15, 25, 35, 50, 70, 100, 140, 200, 280, 400 Hz, 24 or 48 dB/octave, Butterworth.
Notch: 50, 60, 150, 180 Hz and OUT, with the 50 dB rejection bandwidth 2% of center frequency.
High Cut: OUT, 250, 500 or 1000 Hz, 24 or 48 dB/ octave.
Sample Interval: 0.02, 0.03125, 0.0625, 0.125, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 ms.
Correlation: Optional high-speed hardware correlator available in each Geode for fast cycle time with vibrators and pseudo-random (MiniSosie) sources2.
Maximum Record Length: 16,384 samples per channel standard, 65,536 samples per channel optional.
Pre-trigger Data: Up to 4,096 Samples.
Delay: 0 to 9999 ms in 1 sample interval steps.
Data Transmission: Uses reliable Ethernet connections and requires no custom transmission software. Interfaces directly with network capabilities of Windows 98/NT/2K/XP.
Auxiliary Channels: All Geode channels can be programmed as either AUX or DATA. Fixed data and aux channels available in StrataVisor NZ.
Roll Along: Built-in, no external roll box required.
Line Testing: Real time noise monitor displays real-time output from geophones. Optional geophones pulse test helps identify bad geophones and shorted or broken cables2.
Instrument Tests: Optional built-in daily, weekly and monthly testing available2. External laboratory quality test system available to measure noise, crosstalk, dynamic range, gain similarity and trigger accuracy to factory specification.
Data Formats: SEG-2 standard with SGOS. SEG-D and SEG-Y available2.
Single Geode Operating Software (SGOS): Includes full compliment of acquisition, display, plotting, filtering and storage features.
Multiple Geode Operating Software (MGOS): Allows single laptop to control multiple Geodes and adds additional preamp gains, correlation, expanded record length, tape writing, geophone pulse test, expanded test and diagnostics and roll along capability.
StrataVisor NZ Software: Functionally similar to MGOS above but operates on ruggedized NZ field system.
Data Storage: Stores data locally on laptop hard drive for transfer to portable media2.
Plotters: Drives a variety of NT compatible printers including Printrex 4, 8 and 12 inch plotters. Consult factory.
Triggering: Positive, negative or contact closure, software adjustable threshold.
Power: Requires 12V external battery. Uses 0.65W/channel during acquisition, sleep mode reduces power consumption by 70% while in standby.
Environmental: Geode:-30 to 70degrees C. Waterproof and submersible. Withstands a 1 m drop onto concrete on 6 sides and 8 corners. NZ: Starts from +5oC to 40oC. Operates from –5oC to 45oC.
Physical: Geode: 12.2″L x 9 3/4″W x 7″D (31cmL x 24.75cmW x 17.75cm), weighs 3.5 kg.
NZ field PC with no channels: 10.5“L x 18″W x 21“D (26.7cmL x 45.7 cmW x 53.34 cmD), weighs 30 lb (13.5 kg)
Seismic recorder with 3-64 internal channels: 10.5“L x 18″W x 13 “D (26.7cm L x 45.7 cmW x 33 cmD), weighs 20 lb (9 kg)
Operating System: Windows 98/NT/XP/2000.
Data Processing and Interpretation: Includes refraction software with first break picking, layer assignment, depth below each geophone using delay time, refraction tomography and reflection processing software. Consult factory for individual data sheets.
1- Laptop computers are NOT field devices. They are easily damaged by harsh treatment or exposure to extreme environments. They have a short battery life. Geometrics StrataVisor NZ is designed to operate in harsh conditions for extended periods and should be used with the Geode for professional surveys when reliability is important..
2 – Available with MGOS software only.