Remote Sensing Laboratory ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA AVHoTRRA Valerio Lombardo GNV 2007 Progetto Etna

ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA (t+ t) (t) LavaBackground Thermal model (Low Resolution) Identification of the thermal anomaly (Alert) Dual-band constrains The effusion rate estimation Issues

ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA Available Sensors ASTER29/07/2001 MIVIS 29/07/2001 Resolution: 5-8m 30m 1 Km Acquisition: on demand every 16 day 3-5 per day AVHRR 29/07/2001

ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA the radiance detected by the sensor in one band is an average, weighted by the fractional area, of the two radiances related to the different temperatures (Rothery et al ): R tot = f h (R h ) + (1 - f h ) R c RC1 R ( ) = C1 5 (exp(C2/ T) - 1) Planck equation: Background: dual-band technique R 2 tot = f h (R 2 h ) + (1 - f h ) R 2 c R 1 tot = f h (R 1 h ) + (1 - f h ) R 1 c Dual-band technique:

ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA Dual-band solutions allow for calculation of radiant flux (Q lava ) from active flows Q lava = [ f h T h 4 + (1 - f h ) T c 4 ] E r E r = Q tot lava cp lava T+C L Effusion rate Er (Pieri and Baloga 1986; Harris et al. 1997) : Background: effusion rate lava : lava : lava density Cp lava : Cp lava : specific heat capacity T : T : avarage temperature drop throughout the active lava C L : C L : latent heat of crystallization : : average mass of crystals grown in cooling through T Qcon

ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA Methodology We use 3 bands of the MIVIS dataset as input of the system to obtain simultaneous solutions for the three unknowns: T c, T h, f h. R 2 tot = f h (R 2 h ) + (1 - f h ) R 2 c R 1 tot = f h (R 1 h ) + (1 - f h ) R 1 c R 3 tot = f h (R 3 h ) + (1 - f h ) R 3 c 1.53 m 2.19 m m

ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA IDL routine for effusion rate estimation

ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA Landsat 5 and 7 data set Summary of Landsat ETM sensor parameters. Temporal Comparison of Thermal and Geometrical Features INGV database contains 80 Landsat 5 TM and Landsat 7 ETM images covering Etna activity, during 1984 – 2003 period. We applied remote sensing techniques to retrieve the energy flux and effusion rates of active lava flows for each image.

ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA We estimated the energy flux and the effusion rate for every image of our database TIMETIME – 2001 effusion rate estimates

ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA 1984 – 2001 energy flux April - October 1984 March - July 1985 Dicember March 1993 July - December 1997 March 1998 June - September 1998 Febrary - November 1999 January - August 2000 January - April 2001 May - June - July 2001 July - August 2001 Eruptive phases

ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA 1984 – 2001 effusion rate April - October 1984 March - July 1985 Dicember March 1993 July - December 1997 March 1998 June - September 1998 Febrary - November 1999 January - August 2000 January - April 2001 May - June - July 2001 July - August 2001 Eruptive phases