Duration, magnitude, and frequency of subaerial volcano deformation events: New results from Latin America using InSAR and a global synthesis

Abstract

[1] We combine new observations of volcano deformation in Latin America with more than 100 previous deformation studies in other areas of the world to constrain the frequency, magnitude, and duration of subaerial volcano deformation events. We discuss implications for eruptive hazards from a given deformation event and the optimum repeat interval for proposed InSAR satellite missions. We use L band (23.6 cm wavelength) satellite-based interferometric synthetic aperture radar (InSAR) to make the first systematic search for deformation in all volcanic arcs of Latin America (including Mexico, Central America, the Caribbean, and the northern and southern Andes), spanning 2006-2008. We combine L and C band (5.6 cm wavelength) InSAR observations over the southern Andes volcanoes to extend the time series from 2002 to 2008 and assess the capabilities of the different radars: L band gives superior results in highly vegetated areas. Our observations reveal 11 areas of volcano deformation, some of them in areas that were thought to be dormant. There is a lack of observed deformation at several erupting volcanoes, probably due to temporal aliasing. The total number of deforming volcanoes in the central and southern Andes now totals 15 (from observations between 1992 and 2008), comparable to the Alaska/Aleutian arc. Globally, volcanoes deform across a variety of time scales (from seconds to centuries) often without eruption and with no apparent critical observation time scale, although observations made every minute are sometimes necessary to see precursors to eruption.

Satellite radar data reveal short-term pre-explosive displacements and a complex conduit system at Volcán de Colima, Mexico

“…Observations of precursory deformation with InSAR are relatively rare at explosive volcanoes, which has been attributed to the characteristics of the magma reservoir (Chaussard and Amelung, 2012;Ebmeier et al, 2013), a lack of pressurization (Chaussard et al, 2013), the steep topography (Pinel et al, 2011) or temporal aliasing (Fournier et al, 2010). The short temporal baseline and high resolution of our satellite imagery, in combination with a high quality DEM, reduces errors typically associated when using standard resolution InSAR in this type of terrain (Pinel et al, 2011).…”

“…We exploit the radar data interferometrically (InSAR), a method now used routinely to analyze large scale deformation at many volcanoes (Fournier et al, 2010;Ebmeier et al, 2013), and allowing the identification of the depths and geometries of volcanic magma chambers (Dzurisin, 2007). Recent studies have also revealed the importance of both timeliness and spatial resolution when identifying processes associated with basaltic eruptions (Bagnardi et al, 2013;Richter et al, 2013).…”

Stratovolcano growth by co‐eruptive intrusion: The 2008 eruption of Tungurahua Ecuador

“…Point source or penny-shaped cracks [Mogi, 1958;Fialko et al, 2001] produce circular deformation patterns which are inconsistent withthe elongated fringe pattern observed. Models of dike intrusion, including that proposed by Fournier et al [2010], are dominated by horizontal motion and typically have two lobes [Okada, 1985], providing a poor fit.…”

Temporal seismic wave velocity variations at Láscar volcano

“…In the past decade a great progress has been made with geodetic measurements, especially near volcanoes. However, it has been shown using InSAR that the deformation near Láscar volcano is considerable less than other zones within the Andes (Pritchard and Simons, 2004;Henderson y Pritchard, 2013;Fournier et al, 2010). Therefore, it is likely that the source of the inferred velocity change can be due to fluid motion in a very local region, and by small amounts, and can not be detected on a larger scale as observed with InSAR.…”