The WI network is composed of stations geographically distributed all along the Lesser Antilles subduction zone, from Grenada in the south, to St Barthélémy in the north.
The stations all share the following features: (1) very Small Aperture Terminal (VSAT) satellite telemetry, (2) solar power and 10-day battery, (3) multi sensor stations with broadband seismometer (Nanometrics - Trillium120s or 240s) , accelerometer (Kinemetrics - Episensors +/- 2G) and continuous GNSS (Trimble, NetR9), (4) vault and installation design to minimize environmental effects on the instruments.
The vault design addresses several needs: environmental insulation, ground coupling,and instrument security.
The seismic pier, which can accommodate a broadband seismometer, with its insulation, and an accelerometer, is mechanically isolated from the vault walls.
The sensors are separated from the electronics in order to avoid any electric, magnetic and thermal mutual influence.
The vault is further insulated with 6 cm thick Styrofoam panels covering every floor. A “CASSIS” shielding (CASserole SISmologique – seismic cooking pot) which is based on the granite slab and “cooking pot”, attenuates the barometric effects and then decreases the vertical noise level of broadband sensors by several dBs.
An additional mumetal cover on Trillium 240 damps magnetic field variations by 100 dB between 50s and 600s, which is the range of the strongest natural variations during magnetic storms.
Data of this network are fully disseminated in SEED format (Seismic data) or Rinex format (GNSS) in real time (raw data) and after a validation.
The stations all share the following features: (1) very Small Aperture Terminal (VSAT) satellite telemetry, (2) solar power and 10-day battery, (3) multi sensor stations with broadband seismometer (Nanometrics - Trillium120s or 240s) , accelerometer (Kinemetrics - Episensors +/- 2G) and continuous GNSS (Trimble, NetR9), (4) vault and installation design to minimize environmental effects on the instruments.
The vault design addresses several needs: environmental insulation, ground coupling,and instrument security.
The seismic pier, which can accommodate a broadband seismometer, with its insulation, and an accelerometer, is mechanically isolated from the vault walls.
The sensors are separated from the electronics in order to avoid any electric, magnetic and thermal mutual influence.
The vault is further insulated with 6 cm thick Styrofoam panels covering every floor. A “CASSIS” shielding (CASserole SISmologique – seismic cooking pot) which is based on the granite slab and “cooking pot”, attenuates the barometric effects and then decreases the vertical noise level of broadband sensors by several dBs.
An additional mumetal cover on Trillium 240 damps magnetic field variations by 100 dB between 50s and 600s, which is the range of the strongest natural variations during magnetic storms.
Data of this network are fully disseminated in SEED format (Seismic data) or Rinex format (GNSS) in real time (raw data) and after a validation.