*************************************** From: Shellie Rose <srr13@xxxxxxxx> *************************************** The ASTER spaceborne instrument continues to provide unprecedented data of the ongoing eruption of Klyuchevskoy volcano on the Kamchatka peninsula of eastern Russia. This activity is being closely monitored by the Kamchatka Volcanic Eruption Response Team (KVERT), Seismologists at the Kamchatka Branch of Geophysical Services (KBGS) and remotely by the University of Pittsburgh using the ASTER sensor on the NASA Terra satellite. On 1 June, KVERT downgraded the level of concern color code from red to orange as ash-plume heights and associated risks to international aircraft decreased. Recent ASTER data acquired on 5 and 6 June have recorded the continuing effusive phase of the eruption with activity migrating from the N-NW flank to the SE flank of the volcano. These new lava flows were initially reported by KVERT on 31 May, and early signs of their presence were detected in the 29 May ASTER thermal infrared (TIR) data. Data from the most recent satellite overpasses can be found here: http://ivis.eps.pitt.edu/data/Kamchatka/06June2007_Klyuch.pdf http://ivis.eps.pitt.edu/data/Kamchatka/06June2007_Klyuch2.pdf A decorrelation stretch performed on the nighttime 5 June TIR data reveals that the plume is composed primarily of ash with lesser amounts of water/ice and very little SO2, extending >56 km (off the image) to the south-southwest. The daytime TIR data collected ~ 13 hours later shows plume segments or puffs progressively younger in age and increasing ash content from southwest to the southeast. These ash clouds were above the lower-lying weather clouds, but no higher than the volcano's summit. They presumably show a changing wind direction from southwest to southeast with the older and more distant puffs containing less ash, suggesting fallout has taken place over time. The nighttime TIR data from 5 June also recorded a series of thermal anomalies radiating from the summit and occupying 404 (3.3 sq. km) pixels at temperatures 10 C above background (-16 C). The southeastern anomaly and summit crater included 50 pixels (0.4 sq km) at or above saturation at 97 C. Notably, the maximum brightness temperatures of the northern lava flows mentioned in our previous reports had dropped from saturation to ~ 27 C, far too cool to be detected in the shortwave infrared (SWIR). This suggests that effusive activity has ceased to the north and has now concentrated on the east and southeastern flanks. The nighttime SWIR data acquired on 5 June revealed significant thermal output of the two new SE-flows (similar in power to the previous northern flows). The larger lava flow was approximately 2 km in length and ~100 m wide. The smaller, secondary flow to the south was 443 m in length and ~100 m wide. Using the pre-flow slope calculated from the 18 March ASTER-derived DEM and the down-slope change in distance during the 13 hours between the ASTER overpasses, the average flow velocity was calculated to be ~ 26 m/hr. Brightness temperatures of these flows ranged from 356 C around the perimeter to saturation (~465 C) near the center. During the image interval, the number of saturated pixels increased from 133 (0.12 sq. km) to 171 (0.15 sq. km), suggesting that effusive activity had increased. Visible incandescence was observed in both southeastern lava channels of the 15m/pixel visible/near infrared (VNIR) data. Previous maximum VNIR temperatures of the northern lava flows ranged from 856 ? 905 C, and the new flow falls within that range (873 C). It should be noted that pixel-integrated temperatures such as these are an average over 15 sq. m and likely contain some amount of error due to optically thin plumes and/or incomplete correction for solar reflection. The ASTER instrument is made up of three subsystems each with different spatial and spectral resolutions. Data are 15m/pixel in the VNIR, 30 m/pixel in the SWIR, and 90m/pixel in the TIR regions. ASTER will continue to monitor the volcano to assess changes in the thermal, ash, and gas flux throughout this phase of activity. New ASTER day/night data acquisitions are scheduled for 13/14 June, and 21/22 June. ---------------------------------------------- Shellie Rose University of Pittsburgh Department of Geology and Planetary Science SRCC 200 Pittsburgh, PA 15260 ============================================================== 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. ==============================================================
