Electricity + Control February 2019

CABLES + ACCESSORIES

cable features four twisted pairs, surrounded by an aluminium-coated plastic band that acts as screen- ing. The PE outer sheath resists UV light and is transversely waterproof, meaning that it does not allow moisture to penetrate through the sheath. If water penetrates at the ends of the cable, in this case at the connections to the seismometer and the modem in the data centre, or through a tear caused by a sharp object, the water is prevented from spreading through the cable. This is because the cable is filled with petroleum jelly, commonly known as Vaseline. Möllhoff thinks the choice of cable is a good one. The 60-volt direct current power supply to the seismometers is stable, as is the data transmis- sion in both directions via separate wire pairs. This allows the volcanologists to adjust the seismom- eter settings from afar. The measuring system for the first installed seismometer works perfectly, collecting 1.5 gigabytes of data per month and

transmitting it live to Reykjavík and Dublin.

Measurement campaign until the eruption So far, there is nothing to suggest that Hekla might be about to erupt. The measurement campaign is planned to continue until the next eruption oc- curs. The goal is to discover how im- minent eruptions are reflected in the measurement data and to provide insights into developing a permanent early warning system. Such a system could then also be installed on other volcanoes. At any rate, the research goes on; as Möllhoff says, “There are still plenty of volcanoes we have not explored yet, and plenty of unan- swered questions”.

Source: Icelandic Meteorological Office

Electricity + Control

FEBRUARY 2019

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