****************************************** 06 June 2006 ASTER data of Merapi Volcano ****************************************** From: Michael Ramsey <mramsey+@xxxxxxxx> The ASTER instrument is continuing to collect data of Merapi Volcano in an urgent request mode during the current crisis in Indonesia. A unique nighttime/daytime image pair was acquired of the volcano within 12 hours of one another on 06 June 2006. The data have just been downloaded and briefly examined (more analysis will follow). However, both images indicate an increasing level of thermal and plume activity. The daytime image shows an ash-rich plume extending over 40km to the SE, continuing off the image edge (it is likely the plume extends a much longer distance). The presence of ash is also confirmed using the thermal infrared bands of ASTER, which show significantly higher ash abundance where compared to the plume from 30 May (see previous VOLCANO Listserv posting). The visible/near infrared image can be found here: http://ivis.eps.pitt.edu/data/merapi/day-night2.jpg Contoured on the image is the 25 C boundary derived from the nighttime image collected 12 hours later. These data indicate the minimum down-slope extent of the hot pyroclastic material. It is very likely that material traveled further down-slope, but has cooled enough to not be detectable in the ASTER 90m TIR pixels. The thermally elevated material to the SE has increased significantly since the last ASTER image on 30 May and now appears to be as long as the previously-dominant SW flow direction. A comparison of the day versus night TIR-derived temperature images can be found here: http://ivis.eps.pitt.edu/data/merapi/day-night3.jpg A very precursory analysis of the shortwave infrared (SWIR) ASTER channels indicates that temperatures at the summit remain well above 420 C and have increased in areal extent (more analysis will follow). A complete list of all Merapi ASTER images described in my postings to the VOLCANO Listserv can be found here: http://ivis.eps.pitt.edu/data/merapi/ ASTER will continue to observe Merapi during this crisis period. The instrument is unique for volcanic observations because of its 15m - 90m spatial resolution, its ability to be scheduled and point off-nadir, and its ability to collect visible to thermal IR data during both the day and night. For more information on ASTER, please see the NASA website for the instrument: http://asterweb.jpl.nasa.gov/ Cheers, Mike +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Dr. Michael Ramsey, Associate Professor Dept. of Geology & Planetary Science, University of Pittsburgh 4107 O'Hara Street, room 200 SRCC Pittsburgh, PA 15260-3332, USA office: 412-624-8772; fax: 412-624-3914; IVIS Lab: 412-624-8773, IVIS Spectrometer Lab: 412-624-7874 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ============================================================== To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxxx To contribute to the volcano list, send your message to: volcano@xxxxxxxx Please do not send attachments. ==============================================================
