Precursory swarms of long-period events at Redoubt Volcano (1989–1990), Alaska: Their origin and use as a forecasting tool

Chouet, Bernard; Page, Robert A.; Stephens, C. D.; Lahr, John C.; Power, John A.

doi:10.1016/0377-0273(94)90030-2

Cited by 254 publications

(138 citation statements)

References 34 publications

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“…A common source is usually inferred for LP events and tremor based on similarities observed in their spectra, their times of occurrence, and the spatial attenuation of their amplitudes Chouet, 1988;Chouet et al, 1994]. Almendros et al [1997] used array techniques to demonstrate that the apparent slowness vectors for both individual LP events and tremor recorded at Deception Island, Antarctica, were exactly the same, a finding indicative of a common source region.…”

Section: Preliminary Epicenter Location: Geometric Modelmentioning

confidence: 99%

Spatial extent of a hydrothermal system at Kilauea Volcano, Hawaii, determined from array analyses of shallow long‐period seismicity: 2. Results

Almendros¹,

Chouet²,

Dawson³

2001

J. Geophys. Res.

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Section: Preliminary Epicenter Location: Geometric Modelmentioning

confidence: 99%

Spatial extent of a hydrothermal system at Kilauea Volcano, Hawaii, determined from array analyses of shallow long‐period seismicity: 2. Results

Almendros¹,

Chouet²,

Dawson³

2001

J. Geophys. Res.

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“…Swarms of shallow (<5 km) volcanic long-period (LP; 0.2-2 s) events represent a forecasting tool of the climactic stage of volcanic eruptions [Chouet et al, 1994;Chouet, 1996;Sparks et al, 2012]. Seismic signals in ice sheets have been used to infer the timing and propagation of a subglacial outburst flood beneath the West Antarctic Ice Sheet [Winberry et al, 2009].…”

Section: Introductionmentioning

confidence: 99%

Vibrational modes of hydraulic fractures: Inference of fracture geometry from resonant frequencies and attenuation

Lipovsky¹,

Dunham²

2018

Preprint

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Oscillatory seismic signals arising from resonant vibrations of hydraulic fractures are observed in many geologic systems, including volcanoes, glaciers and ice sheets, and hydrocarbon and geothermal reservoirs. To better quantify the physical dimensions of fluid‐filled cracks and properties of the fluids within them, we study wave motion along a thin hydraulic fracture waveguide. We present a linearized analysis, valid at wavelengths greater than the fracture aperture, that accounts for quasi‐static elastic deformation of the fracture walls, as well as fluid viscosity, inertia, and compressibility. In the long‐wavelength limit, anomalously dispersed guided waves known as crack or Krauklis waves propagate with restoring force from fracture wall elasticity. At shorter wavelengths, the waves become sound waves within the fluid channel. Wave attenuation in our model is due to fluid viscosity, rather than seismic radiation from crack tips or fracture wall roughness. We characterize viscous damping at both low frequencies, where the flow is always fully developed, and at high frequencies, where the flow has a nearly constant velocity profile away from viscous boundary layers near the fracture walls. Most observable seismic signals from resonating fractures likely arise in the boundary layer crack wave limit, where fluid‐solid coupling is pronounced and attenuation is minimal. We present a method to estimate the aperture and length of a resonating hydraulic fracture using both the seismically observed quality factor and characteristic frequency. Finally, we develop scaling relations between seismic moment and characteristic frequency that might be useful when interpreting the statistics of hydraulic fracture events.

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“…A sudden increase in either the number or amplitude of LP events is often a sign of volcanic unrest, and LP signals are frequently seen as swarms or groups of repeating events concentrated in time. Identification of LP swarms is important in volcano monitoring because they often precede significant eruptions [Pinatubo Volcano Observatory, 1991;Chouet et al, 1994;Neuberg et al, 2000;Varley et al, 2010].…”

Section: Introductionmentioning

confidence: 99%

Distinguishing high surf from volcanic long‐period earthquakes

Lyons

Haney

Fee

et al. 2014

Geophysical Research Letters

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Repeating long-period (LP) earthquakes are observed at active volcanoes worldwide and are typically attributed to unsteady pressure fluctuations associated with fluid migration through the volcanic plumbing system. Nonvolcanic sources of LP signals include ice movement and glacial outburst floods, and the waveform characteristics and frequency content of these events often make them difficult to distinguish from volcanic LP events. We analyze seismic and infrasound data from an LP swarm recorded at Pagan volcano on 12-14 October 2013 and compare the results to ocean wave data from a nearby buoy. We demonstrate that although the events show strong similarity to volcanic LP signals, the events are not volcanic but due to intense surf generated by a passing typhoon. Seismo-acoustic methods allow for rapid distinction of volcanic LP signals from those generated by large surf and other sources, a critical task for volcano monitoring.

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Precursory swarms of long-period events at Redoubt Volcano (1989–1990), Alaska: Their origin and use as a forecasting tool

Cited by 254 publications

References 34 publications

Spatial extent of a hydrothermal system at Kilauea Volcano, Hawaii, determined from array analyses of shallow long‐period seismicity: 2. Results

Spatial extent of a hydrothermal system at Kilauea Volcano, Hawaii, determined from array analyses of shallow long‐period seismicity: 2. Results

Vibrational modes of hydraulic fractures: Inference of fracture geometry from resonant frequencies and attenuation

Distinguishing high surf from volcanic long‐period earthquakes

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