Synthetic aperture radar (SAR)-based mapping of volcanic flows: Manam Island, Papua New Guinea J. K. Weissel1, K. R. Czuchlewski1,2, and Y. Kim3 1Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, USA 2Department of Earth and Environmental Sciences, Columbia University, New York, USA 3Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
Abstract. We present new radar-based techniques for efficient identification
of surface changes generated by lava and pyroclastic flows, and
apply these to the 1996 eruption of Manam Volcano, Papua New Guinea.
Polarimetric L- and P-band airborne synthetic aperture radar (SAR)
data, along with a C-band DEM, were acquired over the volcano on
17 November 1996 during a major eruption sequence. The L-band data
are analyzed for dominant scattering mechanisms on a per pixel basis
using radar target decomposition techniques. A classification method
is presented, and when applied to the L-band polarimetry, it readily
distinguishes bare surfaces from forest cover over Manam volcano.
In particular, the classification scheme identifies a post-1992 lava
flow in NE Valley of Manam Island as a mainly bare surface and the
underlying 1992 flow units as mainly vegetated surfaces. The
Smithsonian's Global Volcanism Network reports allow us to speculate
whether the bare surface is a flow dating from October or November
in the early part of the late-1996 eruption sequence. This work
shows that fully polarimetric SAR is sensitive to scattering
mechanism changes caused by volcanic resurfacing processes such as
lava and pyroclastic flows. By extension, this technique should
also prove useful in mapping debris flows, ash deposits and volcanic
landslides associated with major eruptions.
Citation: Weissel, J. K., Czuchlewski, K. R., and Kim, Y.: Synthetic aperture radar (SAR)-based mapping of volcanic flows: Manam Island, Papua New Guinea, Nat. Hazards Earth Syst. Sci., 4, 339-346, doi:10.5194/nhess-4-339-2004, 2004.