CRAB System
Mobile seismic system for marine surveys and monitoring on the shelf and in transition zones.
The system based on 4C Ocean Bottom Nodes which are controlled by the system’s lab containers.
Designed for offshore seismic exploration and regional studies.
CRAB Composition
Ocean Bottom Nodes
Operation in any orientation at the seabed
Autonomous operation during 45 days
Battery recharging time is 24 hours
Diameter 245 mm
Height 132 mm
Weight in air 12 kg
CRAB Specifications
Ocean Bottom Nodes
Electric technical specifications
Recorder | 4 channels Orthogonal oriented Geophones: BH-20MT OMNI / GS-ONE OMNI Hydrophone |
ADC | 24 bit, delta-sigma with sample interval 0.25, 0.5, 1, 2, 4 ms |
Gain | 0, 6, 12, 18, 24, 30, 36 dB |
Max input signal | 1.8 V (rms) |
Equivalent input noise | 0.08 – 3 μV (rms) |
Gain accuracy | ≤ 1% |
Instant dynamic range | 126 dB at 0 dB gain |
Flash memory | 32 GB |
Power autonomy | 45 days |
Geophone electric technical specifications
Natural frequency | 15 Hz |
Distortion (in any orientation) | < 0.2% |
Coil resistance with shunt resistor 7.5 kΩ | 1450 Ω |
Open loop sensitivity | 69,2 V/m/s |
Sensitivity at 70% Damping | 15 V/m/s |
Damping | 0.7 |
Hydrophone electric technical specifications
Capacity (at temperature 25°C, pressure 1 atm) | ≥ 9000pF |
Sensitivity | 6 V/Bar |
Lab container
Purpose
- Charging batteries of the Ocean Bottom Nodes
- Controlling the Ocean Bottom Nodes
- Downloading recorded data from the Ocean Bottom Nodes
Specifications
- Up to 400 Ocean Bottom Nodes
- Can be powered by different supply source (220V, 380V, 440V)
CRAB System Features
Can be operated onshore
or at depth up to 500 meters
Repreparation time
is 24 hours max.
Operating temperature
from -10° to +50° C
Contacts
Marine Technical Center Limited Liability Company
+7 812 339-94-84
info@mtcgeo.com
Dvinskaja st., 14A, space 1-n, office 70,
St. Petersburg, Russia, 198035