scholarly journals Observations of volcanic earthquakes and tremor at Deception Island - Antarctica

1999 ◽  
Vol 42 (3) ◽  
Author(s):  
G. Alguacil ◽  
J. C. Almendros ◽  
E. Del Pezzo ◽  
A. Garcia ◽  
J. M. Ibañez ◽  
...  
Keyword(s):  
Volcanic Activity ◽  
High Frequency ◽  
Low Frequency ◽  
Volcanic Tremor ◽  
Shallow Aquifer ◽  
Seismic Events ◽  
Deception Island ◽  
Rapid Phase ◽  
Long Period ◽  
Frequency Phase

Deception Island - South Shetlands, Antarctica is site of active volcanism. Since 1988 field surveys have been carried out with the aim of seismic monitoring, and in 1994 a seismic array was set up near the site of the Spanish summer base in order to better constrain the source location and spectral properties of the seismic events related to the volcanic activity. The array was maintained during the Antarctic summer of 1995 and the last field survey was carried out in 1996. Data show the existence of three different groups (or families) of seismic events: 1) long period events, with a quasi-monochromatic spectral content (1-3 Hz peak frequency) and a duration of more than 50 s, often occurring in small swarms lasting from several minutes to some day; 2) volcanic tremor, with a spectral shape similar to the long period events but with a duration of several minutes (2-10); 3) hybrid events, with a waveform characterised by the presence of a high frequency initial phase, followed by a low frequency phase with characteristics similar to those of the long period events. The high frequency phase of the hybrid events was analysed using polarisation techniques, showing the presence of P waves. This phase is presumably located at short epicentral distances and shallow source depth. All the analysed seismic events show back-azimuths between 120 and 330 degrees from north (corresponding to zones of volcanic activity) showing no seismic activity in the middle of the caldera. Particle motion, Fourier spectral and spectrogram analysis show that the low frequency part of the three groups of the seismic signals have similar patterns. Moreover careful observations show that the high frequency phase which characterises the hybrid events is present in the long period and in the tremor events, even with lower signal to noise ratios. This evidence suggests that long period events are events in which the high frequency part is simply difficult to observe, due to a very shallow source and/or hypocentral distance higher than that of hybrids, while the tremor is composed of rapidly occurring hybrid events. We propose a possible interpretation for the three groups of seismic events. These may be generated by multiple pressure-steps due to the rapid phase change from liquid to vapour in a shallow aquifer which comes in contact with hot materials. The pressure change can put a crack in resonance or excite the generation of multiple surface waves modes in the shallow layered structure.

scholarly journals The Marsquake Catalogue from InSight, Sols 0-478

2020 ◽  
Author(s):  
John Clinton ◽  
Savas Ceylan ◽  
Martin van Driel ◽  
Domenico Giardini ◽  
Simon C. Stähler ◽  
...  
Keyword(s):  
Seismic Data ◽  
High Frequency ◽  
Thermal Stresses ◽  
Low Frequency ◽  
Local Source ◽  
First Year ◽  
Seismic Events ◽  
Long Period ◽  
Seismic Catalogue ◽  
Seismic Origin

The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission began collecting high quality seismic data on Mars from February 2019. This manuscript documents the seismicity observed by SEIS, InSight’s seismometer, since this time until the end of March, 2020. Within the InSight project, the Marsquake Service (MQS) is responsible for prompt review of all seismic data collected by InSight, detection of events that are likely to be of seismic origin, and curation and release of seismic catalogues. In the first year of data collection, MQS have identified 465 seismic events that we interpret to be from regional and teleseismic marsquakes. Seismic events are grouped into 2 different event families: the low frequency family are dominated by energy at long period below 1 second, and the high frequency family primarily include energy at and above 2.4~Hz. Event magnitudes, from Mars-specific scales, range from 1.3 to 3.7. A third class of events with very short duration but high frequency bursts have been observed 712 times. These are likely associated with a local source driven by thermal stresses. This paper describes the data collected so far in the mission and the procedures under which MQS operates; summarises the content of the current MQS seismic catalogue; and presents the key features of the events we have observed so far, using the largest events as examples.

scholarly journals Statistical analysis of Stromboli VLP tremor in the band [0.1–0.5] Hz: some consequences for vibrating structures

2006 ◽  
Vol 13 (4) ◽  
pp. 393-400 ◽  
Author(s):  
E. De Lauro ◽  
S. De Martino ◽  
M. Falanga ◽  
M. Palo
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
Noise Source ◽  
Volcanic Tremor ◽  
Large Data ◽  
Musical Instruments ◽  
Data Set ◽  
Long Period ◽  
Vibrating Structures ◽  
Analyze Time Series

Abstract. We analyze time series of Strombolian volcanic tremor, focusing our attention on the frequency band [0.1–0.5] Hz (very long period (VLP) tremor). Although this frequency band is largely affected by noise, we evidence two significant components by using Independent Component Analysis with the frequencies, respectively, of ~0.2 and ~0.4 Hz. We show that these components display wavefield features similar to those of the high frequency Strombolian signals (>0.5 Hz). In fact, they are radially polarised and located within the crater area. This characterization is lost when an enhancement of energy appears. In this case, the presence of microseismic noise becomes relevant. Investigating the entire large data set available, we determine how microseismic noise influences the signals. We ascribe the microseismic noise source to Scirocco wind. Moreover, our analysis allows one to evidence that the Strombolian conduit vibrates like the asymmetric cavity associated with musical instruments generating self-sustained tones.

Combining Distributed Acoustic Sensing and Beamforming in a Volcanic Environment on Mount Meager, British Columbia.

2021 ◽  
Author(s):  
Sara Klaasen ◽  
Patrick Paitz ◽  
Jan Dettmer ◽  
Andreas Fichtner
Keyword(s):  
British Columbia ◽  
Power Distribution ◽  
High Frequency ◽  
Low Frequency ◽  
Volcanic Tremor ◽  
Extreme Environment ◽  
Volcanic Complex ◽  
Acoustic Sensing ◽  
Distributed Acoustic Sensing ◽  
Volcanic Environment

<p>We present one of the first applications of Distributed Acoustic Sensing (DAS) in a volcanic environment. The goals are twofold: First, we want to examine the feasibility of DAS in such a remote and extreme environment, and second, we search for active volcanic signals of Mount Meager in British Columbia (Canada). </p><p>The Mount Meager massif is an active volcanic complex that is estimated to have the largest geothermal potential in Canada and caused its largest recorded landslide in 2010. We installed a 3-km long fibre-optic cable at 2000 m elevation that crosses the ridge of Mount Meager and traverses the uppermost part of a glacier, yielding continuous measurements from 19 September to 17 October 2019.</p><p>We identify ~30 low-frequency (0.01-1 Hz) and 3000 high-frequency (5-45 Hz) events. The low-frequency events are not correlated with microseismic ocean or atmospheric noise sources and volcanic tremor remains a plausible origin. The frequency-power distribution of the high-frequency events indicates a natural origin, and beamforming on these events reveals distinct event clusters, predominantly in the direction of the main peaks of the volcanic complex. Numerical examples show that we can apply conventional beamforming to the data, and that the results are improved by taking the signal-to-noise ratio of individual channels into account.</p><p>The increased data quantity of DAS can outweigh the limitations due to the lower quality of individual channels in these hazardous and remote environments. We conclude that DAS is a promising tool in this setting that warrants further development.</p>

scholarly journals The coupling between very long period seismic events, volcanic tremor, and degassing rates at Mount Etna volcano

2013 ◽  
Vol 118 (9) ◽  
pp. 4910-4921 ◽  
Author(s):  
Luciano Zuccarello ◽  
Michael R. Burton ◽  
Gilberto Saccorotti ◽  
Christopher J. Bean ◽  
Domenico Patanè
Keyword(s):  
Volcanic Tremor ◽  
Mount Etna ◽  
Seismic Events ◽  
Etna Volcano ◽  
Long Period

scholarly journals Analyzing Low Frequency Seismic Events at Cerberus Fossae as Long Period Volcanic Quakes

2021 ◽  
Author(s):  
Sharon Kedar ◽  
Mark P. Panning ◽  
Suzanne E. Smrekar ◽  
Simon C. Stähler ◽  
Scott D. King ◽  
...  
Keyword(s):  
Low Frequency ◽  
Seismic Events ◽  
Long Period ◽  
Cerberus Fossae

scholarly journals Low-frequency phase measurement with high-frequency squeezing

2012 ◽  
Vol 20 (16) ◽  
pp. 18173 ◽  
Author(s):  
Zehui Zhai ◽  
Jiangrui Gao
Keyword(s):  
High Frequency ◽  
Phase Measurement ◽  
Low Frequency ◽  
Frequency Phase

Results of seismic monitoring surveys of Deception Island volcano, Antarctica, from 1999–2011

2012 ◽  
Vol 24 (5) ◽  
pp. 485-499 ◽  
Author(s):  
Enrique Carmona ◽  
Javier Almendros ◽  
Inmaculada Serrano ◽  
Daniel Stich ◽  
Jesús M. Ibáñez
Keyword(s):  
Volcanic Tremor ◽  
Local Network ◽  
South Shetland Islands ◽  
Deception Island ◽  
Seismic Arrays ◽  
Shetland Islands ◽  
Long Period ◽  
Spatially Homogeneous ◽  
Regional Stresses ◽  
Seismic Crisis

AbstractDeception Island volcano (South Shetland Islands, Antarctica) has been monitored in summer surveys since 1994. We analyse the seismicity recorded from 1999–2011 with a local network and seismic arrays. It includes long-period (LP) events, volcanic tremor episodes and volcano-tectonic (VT) earthquakes. Long-period events are conspicuous, ranging from 58 (2007–08) to 2868 events (2003–04). The highest number of LP events in one day is 243 on 2 February 2001, and there are several discrete periods of intense LP activity. These variations may be related to alterations in the shallow hydrothermal system of Deception Island. The number of VT earthquakes recorded during the surveys range from 4 (2008–09) to 125 (2007–08). In some periods VT distributions are temporally and spatially homogeneous, with a generally low level of seismicity. In other periods we observe a peak of VT activity lasting a few days, concentrated in a particular area. These two patterns may respond to different processes, involving regional stresses and local tectonic destabilization induced by volcanic activity. Overall, this study indicates that over the period 1999–2011 the volcano presented a moderate level of seismicity, and suggests that there has been no significant reactivation of the volcano since the 1999 seismic crisis.

Design and Research on Piezoelectric Acceleration Geophone

2012 ◽  
Vol 468-471 ◽  
pp. 826-830 ◽  
Author(s):  
Ya Min Xing ◽  
Sheng Hu Liu ◽  
Dong Xu Wang
Keyword(s):  
High Frequency ◽  
Detection Method ◽  
Low Frequency ◽  
Response Characteristic ◽  
Piezoelectric Crystal ◽  
Field Test Result ◽  
Test Result ◽  
Higher Sensitivity ◽  
Frequency Phase ◽  
Piezoelectric Acceleration

A kind of piezoelectricity acceleration geophone is studied and discussed. carried on its amplitude frequency, phase-frequency characteristic theoretically, obtained the primary factor of the influence on frequency response, and improved in the piezoelectric crystal choice and geophone structure. The theory and the field test result indicated that, this piezoelectricity acceleration geophone has better response characteristic on low frequency and the high-frequency as well as a higher sensitivity, it is one better detection method.

scholarly journals A statistical framework to assess cross-frequency coupling while accounting for confounding analysis effects

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Jessica K Nadalin ◽  
Louis-Emmanuel Martinet ◽  
Ethan B Blackwood ◽  
Meng-Chen Lo ◽  
Alik S Widge ◽  
...  
Keyword(s):  
High Frequency ◽  
Statistical Power ◽  
Brain Activity ◽  
Low Frequency ◽  
Modeling Framework ◽  
Frequency Coupling ◽  
Phase Amplitude ◽  
Cross Frequency Coupling ◽  
Frequency Phase

Cross frequency coupling (CFC) is emerging as a fundamental feature of brain activity, correlated with brain function and dysfunction. Many different types of CFC have been identified through application of numerous data analysis methods, each developed to characterize a specific CFC type. Choosing an inappropriate method weakens statistical power and introduces opportunities for confounding effects. To address this, we propose a statistical modeling framework to estimate high frequency amplitude as a function of both the low frequency amplitude and low frequency phase; the result is a measure of phase-amplitude coupling that accounts for changes in the low frequency amplitude. We show in simulations that the proposed method successfully detects CFC between the low frequency phase or amplitude and the high frequency amplitude, and outperforms an existing method in biologically-motivated examples. Applying the method to in vivo data, we illustrate examples of CFC during a seizure and in response to electrical stimuli.

scholarly journals Interaction between seismicity and deformation on different time scales in volcanic areas: Campi Flegrei and Stromboli

2019 ◽  
Vol 52 ◽  
pp. 1-8 ◽  
Author(s):  
Mariarosaria Falanga ◽  
Enza De Lauro ◽  
Simona Petrosino ◽  
Salvatore De Martino
Keyword(s):  
Stationary Phase ◽  
Time Scales ◽  
Volcanic Activity ◽  
High Frequency ◽  
Campi Flegrei ◽  
Feeding System ◽  
Low Frequencies ◽  
Long Period ◽  
Volcanic Processes ◽  
Different Time Scales

Abstract. We study oscillations recorded at Stromboli and Campi Flegrei by different sensors: seismometers, strainmeters and tiltmeters. We examine both the high-frequency (>0.5 Hz) portion of the spectrum and very long period signals up to tidal scales. In this context, seismicity and deformation are investigated on different time scales (from minutes to days/years) in order to identify the basic elements of their interaction, whose understanding should provide new insights on the predictive models. In this work, the strict relation of tides and volcanic processes is shown. At Stromboli, indeed the transition from the stationary phase to the non-stationary phase seems to have a tidal precursor that is related to the duration of the crisis. The subsequent volcanic activity is interpreted as the response of the volcano to restore the equilibrium condition. The moveout from equilibrium produces, first, variations in the standard statistics of explosions, then leads to effusive stage and to a pressure drop in the shallow feeding system. That process induces the nucleation of a gas bubble and the excitation of low frequencies. Campi Flegrei seismicity shows a correlation between the diurnal solar solid tide and the energy released by the long period signals, indicating that the whole mechanism is modulated on a tidal scale. In other words, in the case of Stromboli, a departure from the equilibrium state is marked by solid tide variations in a certain frequency band. On the other hand, at Campi Flegrei diurnal to annual solid tides modulate an increase of volcanic activity.

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