ETNA RADIO OBSERVATORY
Live data from NICOLOSI (CT), Etna Park, Sicily
Maintained by Rosario Catania - Alessandro Longo - Salvatore Caffo Salvatore Spina - Luca Catania
thanks to Renato Romero (vlf.it) for the idea of layout
(To see on google map click this link http://g.co/maps/73ffv (Lat. 37°37'52.45"N - Long. 15°1'20.26"E)
This monitoring station is placed in the Etna Park that extends from the summit of the volcano to the towns surrounding it. Beautiful not only for its eruptions and for its lava flows, but also for the unique environment surrounding it, rich in sounds, perfumes, and colors. An enchanting landscape protected by a park you cannot miss the opportunity to visit if you are in Sicily.
System 1: INDUCTION COIL
Realized with 14 km of 0.22 mm enamelled copper wire (about 5 kg) wrapped on a high permeability core, made by 130 insulated iron rods 0.6 cm thikness and 2 meters long, for a total weight of 120 kg (!).
A low noise preamplifier, made with an OP27 frontend as an unbalanced differential amplifier, supplies the needed amplification to drive the sound card line input directly. Power comes from a local battery recharged by a solar panel.
ERO COIL - credits: www.etna-ero.it
ERO COIL core - credits: www.etna-ero.it
ELF and ULF MAGNETIC FIELD
Here below the first LIVE spectrogram, uSchumann resonances are marked in right side of the picture. Bottom part zooms on the 0,1 to 4 Hz range.
FFT resolution 10,5 mHz, scroll time 40 seconds.pdated every hour. It shows the last 8 hours ELF and ULF activity, as received by our coil (magnetic field).
ERO an example of a spectrogram , source COIL 8 hrs (click to open live view) - credits: www.etna-ero.it
Following the same signal, in 1 hour strips. Picture updated every hour.
This is the frequency range of schumann resonances, and a zone of deep interest to us, for the study of possible interaction of magmatic flow with the terrestrial magnetic field. FFT resolution 168 mHz, scroll time 4.6 seconds.
ERO an example of a spectrogram , source COIL 1 hr (click to open live view) - credits: www.etna-ero.it
Last spectrogram coming from coil shows daily strips, useful to compare activity from day to day, and to find anomalies. Picture updated every hour.
Scroll time 109 seconds and FFT resolution 10,5 mHz.
ERO an example of a spectrogram , source COIL 24 hrs (click to open live view) - credits: www.etna-ero.it
System 2: ORTHOGONAL LOOP
IdealLoop H301 system: http://www.vlf.it/feletti2/idealloop.html . Compact loop to receive VLF from 8 Hz to 20 kHz, with two 50 x 50 cm squared orthogonal loops.
ERO orthogonal loop- credits: www.etna-ero.it
RDF low freqeuncy magnetic field. Color indicates signals incoming direction.
Scroll time 11188 mS , FFT resolution 84 mHz.
ERO an example of a spectrogram , source orthogonal loop 2 hrs (click to open live view) - credits: www.etna-ero.it
And by the same reception system, the hourly multi strips.
Scroll time 4600 mS , FFT resolution 168 mHz.
ERO an example of a spectrogram , source orthogonal loop multistrips (click to open live view) - credits: www.etna-ero.it
RDF VLF magnetic field.
Scroll time 11 sec FFT resolution 91 mHz. Signal pre-filtered with Paul Nicholson's filter to reduce the hum noise.
ERO an example of a spectrogram , source orthogonal loop 2 hrs VLF (click to open live view) - credits: www.etna-ero.it
System 3: GEOPHONE
Geophone Multistrip hourly representation, useful for local seismic and vulcanic events correlation.
Scroll time 4.6 sec, updated every hour.
ERO an example of a spectrogram , source GEOPHONE multi strips (click to open live view) - credits: www.etna-ero.it