Seismic Stations

The SGS applies the structural engineering standards, designed by the Nanometrics Inc. in the construction of seismic stations. The aerial image shows the typical arrangement of the components of a seismic telemetry station. The station is protected by a 2.3-meter high barbed-wire fence for security. A two-meter-deep insulated vault was drilled and constructed, where the broadband sensors were placed over a concrete base on the bedrock. The sensors are insulated with thermal wool to minimize the impacts of temperature variations. The station’s communication equipment transmits information from the vast remote sites via satellite to the SGS main seismic data processing center. The satellite channel is operated through regular commands from the SGS seismic center. The image shows a chamber with a white cover in the upper left part of the station. It is placed away from the rest of the equipment to reduce the effects of wind noises. The electronic data instrumentation and batteries are placed in the two chambers near the dish and solar panels.

A remote seismic station with satellite telemetry.

The equipment in each broadband seismic station include the following:

• Seismometer sensor:

A device for converting seismic wave velocities into digital signals. The network uses several types of this sensor.

• CENTAUR Digitizer

A device for converting the analog electrical signals into digital signals, which are stored in the device and transmitted through the communication system to the main center of the national network. It includes a GPS for timing accuracy.

• VSAT Communication System:

A communication system that transmits and receives data through satellites and uses the VAST technology, which allows the use of a relatively small antenna with a diameter of 1.2 m. It requires an installation base with dimensions of approximately 4 sq. m. The system consists of an antenna and a Cygnus transceiver, installed behind the antenna and contains a GPS for timing accuracy to achieve synchronization between the stations and the reception center. Transmission and reception are carried out through a channel of the National Center for Earthquakes and Volcanoes (NCEV) on the Arabsat satellite.

• Power System

Diagram of the main components of a satellite telemetry seismic station

The power system supplies all components with their electrical needs and is consist of:

• three solar cells, 85 watts each, and similar alternatives, installed on a steel base with a dimension of about 2 m x 1 m.
• a solar cell charge controller for appropriate battery charging according to the battery type.
• three maintenance-free solar batteries with a capacity of 100 amps and an approximate weight of 30 kg each.