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

2. 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

3. 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

4. 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. 1988 ): 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:

5. 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

6. 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 11.36 m

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

8. 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.

9. ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA We estimated the energy flux and the effusion rate for every image of our database TIMETIME 1984 2001 1984 – 2001 effusion rate estimates

10. ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA 1984 – 2001 energy flux April - October 1984 March - July 1985 Dicember 1991 - 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

11. ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA 1984 – 2001 effusion rate April - October 1984 March - July 1985 Dicember 1991 - 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