Precursors to dyke-fed eruptions at basaltic volcanoes: insights from patterns of volcano-tectonic seismicity at Kilauea volcano, Hawaii

Abstract

To investigate the physical controls on volcanotectonic (VT) precursors to eruptions and intrusions at basaltic volcanoes, we have analyzed the spatial and temporal patterns of VT earthquakes associated with 34 eruptions and 23 dyke intrusions that occurred between 1960 and 1983 at Kilauea, in Hawaii. Eighteen of the 57 magmatic events were preceded by an acceleration of the mean rate of VT earthquakes located close to the main shallow magma reservoir. Using a maximum-likelihood technique and the Bayesian Information Criterion for model preference, we demonstrate that an exponential acceleration is preferred over a power-law acceleration for all sequences. These sequences evolve over time-scales of weeks to months and are consistent with theoretical models for the approach to volcanic eruptions based on the growth of a population of fractures in response to an excess magma pressure. Among the remaining 40 magmatic events, we found a significant correlation between swarms of VT earthquakes located in the mobile south-flank of Kilauea and eruptions and intrusions. The behaviour of these swarms suggests that at least some of the magmatic events are triggered by transient episodes of elevated rates of aseismic flank movement, which could explain why many eruptions and intrusions are not preceded by longer-term precursory signals. In none of the 57 cases could a precursory sequence be used to distinguish between the approach to an eruption or an intrusion, so that, even when a precursory sequence is recognized, there remains an empirical chance of about 40% (24 intrusions from 57 magmatic events) of issuing a false alarm for an imminent eruption.

An accelerating precursor to predict “time-to-failure” in creep and volcanic eruptions

“…For both the classical FFM (Voight, 1988(Voight, , 1989Kilburn and Voight, 1998;De la Cruz-Reyna and Reyes-Davila, 2001;Kilburn and Petley, 2003;Sparks, 2003;Smith et al, 2007;Lengliné et al, 2008;Lavallée et al, 2008;Bell et al, 2011aBell et al, , 2011bBell et al, , 2013Bell and Kilburn, 2012;Kilburn, 2012;Boué et al, 2015;Salvage and Neuberg, 2016) and the present method, the signal has to be differentiated with respect to time and inverted, hence large fluctuations introduced by these operations pose an important limitation in terms of real-time operational usage. In the relation of Eq.…”

“…Rates of ground deformation and of local fracturing of the crust or volcanic edifice (Voight, 1988;Cornelius and Voight, 1995;Kilburn and Voight, 1998;De la Cruz-Reyna and Reyes-Davila, 2001; Kilburn and Petley, 2003;Sparks, 2003;Smith et al, 2007;Lengliné et al, 2008;Bell and Kilburn, 2012;Kilburn, 2012;Boué et al, 2015;Salvage and Neuberg, 2016) commonly accelerate before volcanic eruptions. Accelerating creep deformation has also been suggested as a method to predict landslides (Saito, 1969;Kilburn and Petley, 2003;Petley et al, 2005).…”

“…Thus, by linearly extrapolating the curve of the inverse rate to zero, the failure time t f can be determined as the intersection with the time axis (Voight, 1988(Voight, , 1989Kilburn and Voight, 1998;De la Cruz-Reyna and Reyes-Davila, 2001;Kilburn and Petley, 2003;Sparks, 2003;Smith et al, 2007;Lengliné et al, 2008;Lavallée et al, 2008;Bell and Kilburn, 2012;Kilburn, 2012), representing an infinite deformation rate. This method works well in retrospective prediction for such laboratory experiments, landslides, and volcanic eruptions (Voight, 1988;Voight, 1994, 1995;Kilburn and Voight, 1998;Murray and Ramirez Ruiz, 2002;Budi-Santoso et al, 2013).…”

Rational volcanic hazard forecasts and the use of volcanic alert levels

“…Bayesian approaches are often used in conjunction with Event Trees (e.g., Newhall and Hoblitt 2002;Marzocchi et al 2004Marzocchi et al , 2008Newhall and Pallister 2015, and references therein), that represent the complex ramification of possible outcomes, each one quantified as a probability distribution which is allowed to evolve as long as new information is added (e.g., when new observations are available). To-date, Bayesian approaches have been employed in a large number of situations in volcanology, including forecasts of volcanic hazards over the shortterm (Aspinall et al 2003(Aspinall et al , 2006Marzocchi et al 2008; Lindsay et al 2010;Brancato et al 2011Brancato et al , 2012Bell and Kilburn 2012;Marzocchi and Bebbington 2012;Sandri et al 2009Sandri et al , 2012Selva et al 2012Selva et al , 2014Garcia-Aristizabal et al 2013;Anderson and Segall 2013;Rouwet et al 2014;Aspinall and Woo 2014;Sobradelo et al 2015;Boue et al 2015;Tonini et al 2016;Bartolini et al 2016) as well as over the long-term (Martin et al 2004;Baxter et al 2008;Neri et al 2008;Orsi et al 2009;Marzocchi et al 2008Marzocchi et al , 2010Sobradelo and Martì 2010;Passarelli et al 2010a, b;Selva et al 2012;Marzocchi and Bebbington 2012;Sandri et al 2012Sandri et al , 201...…”

When probabilistic seismic hazard climbs volcanoes: the Mt. Etna case, Italy – Part 1: Model components for sources parameterization

“…In fact, seismic swarms located here before the 2001, 2002, 2004 and 2008 eruptions are interpreted as a consequence of stress field variations induced by the process of magma rising and dyke emplacement Gambino et al, 2004;Alparone et al, 2012;Sicali et al, 2015). Conversely, for the flanks of the volcano, especially the eastern one hosting the seismic sources relevant to seismic hazard, the IET distribution shows a prevalence of uncorrelated events, i.e., behavior more similar to a tectonic domain than a volcanic one (see Traversa and Grasso, 2010;Bell and Kilburn, 2012). The role of a different, wider stress field acting in the Timpe area -a structurally homogeneous domain characterized by a general east-west extension (Bousquet and Lanzafame, 2004) -is also proved by the analyses of long time series of geodetic and seismic data (Bruno et al, 2012;Solaro et al, 2010;Bozzano et al, 2013;Palano, 2016, and references therein), highlighting the influence of large-scale instability processes where the strain is released by a steady process on decennial timescale .…”