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Titel |
IS42 Graciosa (Azores): A new IMS certified infrasound station in the North Atlantic |
VerfasserIn |
Nicolau Wallenstein, João Luís Gaspar, Alfred Kramer, Juraci Carvalho, Paola Campus, Georgios Haralabus, João Gregório |
Konferenz |
EGU General Assembly 2011
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 13 (2011) |
Datensatznummer |
250056649
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Zusammenfassung |
After several years and attempts to establish an International Monitoring System (IMS)
infrasound station in the Azores Islands, the cooperation between the Preparatory
Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), the
Azores Government, the Centre of Volcanology and Geological Risks Assessment
(CVARG) and the Santa Cruz da Graciosa Municipality (CMSCG), allowed the
construction, installation and certification of the IS42 Graciosa station during the year of
2010.
Graciosa is one of the nine volcanic islands that constitute the Azores archipelago, located
in the middle of the North Atlantic Ocean where the North American, Eurasian and African
lithospheric plates interact. Located in the Central Group of the Azores Islands, between
39º-39º06’Nº and 27º56’-28º05’W, Graciosa has an area of 60.7 km2 and a maximum altitude
of 402 m asl. With an estimated population of 4938 (2009), it has a commercial harbour and
an aerodrome for regional flights, which guarantee the connections to the main populated
islands of the archipelago.
The station IS42 Graciosa was built a bit towards SE of the central part of the island, in a
heavily forested area that grows over recent basaltic lava flows. The station array comprises
eight data acquisition elements (H1 to H8) and one central recording facility (CRF). The
spatial distribution of the elements in the array is arranged in two groups following a
broad geometry of one pentagon and an internal triangle. The side’s lengths of
those two geometric figures vary from an average of about 1km on the first and
around 200 m on the later. Each element array element has 230V independent power
supply from the public grid and all the elements are linked to the CRF by optical
fiber.
In each element a vault, four pipe rosettes are linked to a MARTEC CEA MB2005
microbarometer which signals are digitized in a Nanometrics Europa T and transmitted via a
Telesto optical fiber modem to the CRF. Time synchronisation is performed by a GPS
receiver. In H1 meteorological data acquired by a thermometer and an anemometer are
digitized trough a second Europa T. Data received in the CRF is processed by a PC running
on Linux and transmitted by satellite to the International Data Centre (IDC) in
Vienna.
The Centre of Volcanology and Geological Risks Assessment (CVARG) of the University
of Azores will assure the operation and maintenance of the station. The access to the IMS
data will allow improving its seismo-volcanic monitoring capabilities in order to enhance its
response to the Azorean Civil Defence authorities and future developments in atmospheric
studies. |
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