TY - JOUR
T1 - Lava lakes on Io
T2 - Observations of Io's volcanic activity from Galileo NIMS during the 2001 fly-bys
AU - Lopes, Rosaly M C
AU - Kamp, Lucas W.
AU - Smythe, William D.
AU - Mouginis-Mark, Peter
AU - Kargel, Jeff
AU - Radebaugh, Jani
AU - Turtle, Elizabeth P.
AU - Perry, Jason
AU - Williams, David
AU - Carlson, R. W.
AU - Douté, S.
N1 - Funding Information:
We thank the Galileo Flight Team for their dedication and hard work in making the Io flybys successful, in particular, Frank Leader, Marcia Segura, Robert Mehlman, James Shirley, and Yanhua Anderson. Imke de Pater and Franck Marchis kindly provided data for Table 2 . This paper was much improved as a result of reviews by David Rothery, Susan Sakimoto, and Robert Howell. Part of the research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Rosaly Lopes was partly funded under grant PGG02-0079-0211 from NASA's Planetary Geology Program.
PY - 2004/5
Y1 - 2004/5
N2 - Galileo's Near-Infrared Mapping Spectrometer (NIMS) obtained its final observations of Io during the spacecraft's fly-bys in August (I31) and October 2001 (I32). We present a summary of the observations and results from these last two fly-bys, focusing on the distribution of thermal emission from Io's many volcanic regions that give insights into the eruption styles of individual hot spots. We include a compilation of hot spot data obtained from Galileo, Voyager, and ground-based observations. At least 152 active volcanic centers are now known on Io, 104 of which were discovered or confirmed by Galileo observations, including 23 from the I31 and I32 Io fly-by observations presented here. We modify the classification scheme of Keszthelyi et al. (2001, J. Geophys. Res. 106 (E12) 33 025-33 052) of Io eruption styles to include three primary types: promethean (lava flow fields emplaced as compound pahoehoe flows with small plumes < 200 km high originating from flow fronts), pillanian (violent eruptions generally accompanied by large outbursts, > 200 km high plumes and rapidly-emplaced flow fields), and a new style we call "lokian" that includes all eruptions confined within paterae with or without associated plume eruptions). Thermal maps of active paterae from NIMS data reveal hot edges that are characteristic of lava lakes. Comparisons with terrestrial analogs show that Io's lava lakes have thermal properties consistent with relatively inactive lava lakes. The majority of activity on Io, based on locations and longevity of hot spots, appears to be of this third type. This finding has implications for how Io is being resurfaced as our results imply that eruptions of lava are predominantly confined within paterae, thus making it unlikely that resurfacing is done primarily by extensive lava flows. Our conclusion is consistent with the findings of Geissler et al. (2004, Icarus, this issue) that plume eruptions and deposits, rather than the eruption of copious amounts of effusive lavas, are responsible for Io's high resurfacing rates. The origin and longevity of islands within ionian lava lakes remains enigmatic.
AB - Galileo's Near-Infrared Mapping Spectrometer (NIMS) obtained its final observations of Io during the spacecraft's fly-bys in August (I31) and October 2001 (I32). We present a summary of the observations and results from these last two fly-bys, focusing on the distribution of thermal emission from Io's many volcanic regions that give insights into the eruption styles of individual hot spots. We include a compilation of hot spot data obtained from Galileo, Voyager, and ground-based observations. At least 152 active volcanic centers are now known on Io, 104 of which were discovered or confirmed by Galileo observations, including 23 from the I31 and I32 Io fly-by observations presented here. We modify the classification scheme of Keszthelyi et al. (2001, J. Geophys. Res. 106 (E12) 33 025-33 052) of Io eruption styles to include three primary types: promethean (lava flow fields emplaced as compound pahoehoe flows with small plumes < 200 km high originating from flow fronts), pillanian (violent eruptions generally accompanied by large outbursts, > 200 km high plumes and rapidly-emplaced flow fields), and a new style we call "lokian" that includes all eruptions confined within paterae with or without associated plume eruptions). Thermal maps of active paterae from NIMS data reveal hot edges that are characteristic of lava lakes. Comparisons with terrestrial analogs show that Io's lava lakes have thermal properties consistent with relatively inactive lava lakes. The majority of activity on Io, based on locations and longevity of hot spots, appears to be of this third type. This finding has implications for how Io is being resurfaced as our results imply that eruptions of lava are predominantly confined within paterae, thus making it unlikely that resurfacing is done primarily by extensive lava flows. Our conclusion is consistent with the findings of Geissler et al. (2004, Icarus, this issue) that plume eruptions and deposits, rather than the eruption of copious amounts of effusive lavas, are responsible for Io's high resurfacing rates. The origin and longevity of islands within ionian lava lakes remains enigmatic.
KW - Io
KW - Satellites of Jupiter
KW - Volcanism
UR - http://www.scopus.com/inward/record.url?scp=2442645451&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=2442645451&partnerID=8YFLogxK
U2 - 10.1016/j.icarus.2003.11.013
DO - 10.1016/j.icarus.2003.11.013
M3 - Article
AN - SCOPUS:2442645451
SN - 0019-1035
VL - 169
SP - 140
EP - 174
JO - Icarus
JF - Icarus
IS - 1
ER -