Rapid deformation of Kilauea Volcano: Global Positioning System measurements between 1990 and 1996

Abstract

Campaign Global Positioning System (GPS) measurements from 1990 to 1996 are used to calculate surface displacement rates on Kilauea Volcano, Hawaii. The GPS data show that the south flank of the volcano, which has generated several large earthquakes in the past 3 decades, is displacing at up to ∼8 cm/yr to the south‐southeast. The summit and rift zones are subsiding, with maximum subsidence rates of ∼8 cm/yr observed a few kilometers south of the summit caldera. Elastic dislocation modeling of the GPS data suggests that the active sources of deformation include deep rift opening along the upper east and east rift zone, fault slip along a subhorizontal fault near the base of the volcano, and deflation near the summit caldera. A nonlinear optimization algorithm was used to explore the parameter space and to find the best fitting source geometry. There is a broad range of model geometries that fit the data reasonably well. However, certain models can be ruled out, including those that have shallow rift opening or shallow fault slip. Some offshore, aseismic slip on a fault plane that dips between 25° northnorthwest and 8° south‐southeast is required. Best fitting slip and rift opening rates are 23–28 cm/yr, although rates as low as 10 cm/yr are permitted by the data.

Slope failure and volcanic spreading along the submarine south flank of Kilauea volcano, Hawaii

“…Convergence between Kilauea and Mauna Loa may have resulted from generally south directed gravitational stresses along this portion of the flank, directed radially away from Kilauea's summit. Rupture of the shallow flank and western boundary fault enabled downslope slumping, accompanied by continuing convergence, matching present-day ground motions [e.g., Owen et al, 2000]. Alternatively, the west dipping strata in Nali'ikakani Ridge represent nearshore fragmental basalt deposits comparable to those accumulating below the lava entry to the northeast (Figure 1).…”

“…The central embayment is white and midslope basin is speckled. GPS ground displacement vectors resolved for time interval 1990 -1996 [Owen et al, 2000] are superimposed. EPM 1 -2 Tilling et al, 1976;Lipman et al, 1985].…”

“…[8] Seaward flank displacements have become more clearly resolved in recent years [e.g., Owen et al, 1995Owen et al, , 2000Delaney et al, 1993Delaney et al, , 1998]. For the time period 1990 -1996, uninterrupted by large flank earthquakes, global positioning system (GPS) measurements indicate that the surface of the south flank has crept seaward at rates up to 10 cm/yr [Owen et al, 1995].…”

“…Flank motion is in response to gravitational relaxation of the volcanic edifice, assisted by pressurized magma beneath the summit and rift zones [e.g., Swanson et al, 1976;Dieterich, 1988;Iverson, 1995;Delaney and Denlinger, 1999], generally termed volcanic spreading [e.g., Borgia, 1994]. Seaward displacement is accommodated by slip along a decollement horizon modeled near the base of the volcano [e.g., Owen et al, 1995Owen et al, , 2000, probably facilitated by sediments on the oceanic plate [e.g., Nakamura, 1980;Iverson, 1995] or viscous dunite beneath the edifice [Clague and Denlinger, 1994].…”

Rift zone reorganization through flank instability in ocean island volcanoes: an example from Tenerife, Canary Islands

“…One hypothesis suggests that dike swarms may push a volcano flank seaward and thus facilitate fault slip of huge edifice segments (Clague and Denlinger 1994;Iverson 1995;Elsworth and Voight 1996;Cayol et al 2000). An alternative hypothesis favors the passive control of intrusive rift zones when a flank deforms gravitationally (Delaney et al 1998;Owen et al 2000;Walter and Troll 2003). There is growing evidence that the number and orientations of dike swarms in volcanic edifices are largely controlled by the near-surface imbalance that arises from the instability of volcano flanks.…”