Automatic Recognition of Long Period Events From Volcano Tectonic Earthquakes at Cotopaxi Volcano

2016 ◽  
Vol 54 (9) ◽  
pp. 5247-5257 ◽  
Author(s):  
Roman A. Lara-Cueva ◽  
Diego S. Benitez ◽  
Enrique V. Carrera ◽  
Mario Ruiz ◽  
Jose Luis Rojo-Alvarez
Keyword(s):  
Automatic Recognition ◽  
Long Period ◽  
Cotopaxi Volcano ◽  
Tectonic Earthquakes

scholarly journals The first Long Period earthquake detected in the background seismicity at Mt. Vesuvius

2013 ◽  
Vol 56 (4) ◽  
Author(s):  
Paola Cusano ◽  
Simona Petrosino ◽  
Francesca Bianco ◽  
Edoardo Del Pezzo
Keyword(s):  
Moment Tensor ◽  
Low Frequency ◽  
Seismic Moment Tensor ◽  
Spectral Content ◽  
Long Period ◽  
Tectonic Events ◽  
Duration Magnitude ◽  
Background Seismicity ◽  
Tectonic Earthquakes ◽  
The Hilbert Transform

<p>The typical earthquakes occurring at Mt. Vesuvius are Volcano-Tectonic. On July 20, 2003, an unusual earthquake with low and narrow frequency content was detected. The seismograms presented an emergent onset and a nearly monochromatic spectrum at all stations of the Osservatorio Vesuviano (Istituto Nazionale di Geofisica e Vulcanologia) seismic network. The event was located at about 4 km b.s.l. close to the crater axis and an equivalent duration magnitude of 0.6 was estimated. The nature of this event was investigated by comparing its features with those of two typical Volcano-Tectonic earthquakes occurred inside the same source volume. We compared the spectral content calculating the spectrograms and the coda patterns using the Hilbert Transform. A Seismic Moment Tensor inversion was performed on the low frequency earthquake. The focal mechanisms for the two Volcano-Tectonic earthquakes were estimated with a classical technique and resulted compatible with the stress field acting on the volcano. Taking into account the clear differences with the typical Volcano-Tectonic events as well as the peculiarities retrieved from our analyses (monochromatic, low frequency spectral content, and sustained coda) and also some geochemical observations, we classify the unusual low frequency seismic event detected at Mt. Vesuvius as Long Period earthquake and propose that its origin could be linked to a pressure drop in the deep hydrothermal system.</p>

A deep learning approach for automatic recognition of seismo-volcanic events at the Cotopaxi volcano

2021 ◽  
Vol 409 ◽  
pp. 107142
Author(s):  
Fernando Lara ◽  
Román Lara-Cueva ◽  
Julio C. Larco ◽  
Enrique V. Carrera ◽  
Rubén León
Keyword(s):  
Deep Learning ◽  
Automatic Recognition ◽  
Learning Approach ◽  
Volcanic Events ◽  
Cotopaxi Volcano

Feature selection of seismic waveforms for long period event detection at Cotopaxi Volcano

2016 ◽  
Vol 316 ◽  
pp. 34-49 ◽  
Author(s):  
R.A. Lara-Cueva ◽  
D.S. Benítez ◽  
E.V. Carrera ◽  
M. Ruiz ◽  
J.L. Rojo-Álvarez
Keyword(s):  
Feature Selection ◽  
Event Detection ◽  
Long Period ◽  
Seismic Waveforms ◽  
Cotopaxi Volcano ◽  
Selection Of ◽  
Long Period Event

Source process of very-long-period events accompanying long-period signals at Cotopaxi Volcano, Ecuador

2008 ◽  
Vol 176 (1) ◽  
pp. 119-133 ◽  
Author(s):  
Indira Molina ◽  
Hiroyuki Kumagai ◽  
Alexander García-Aristizábal ◽  
Masaru Nakano ◽  
Patricia Mothes
Keyword(s):  
Source Process ◽  
Long Period ◽  
Cotopaxi Volcano

Reliable automatic detection of long-period volcanic earthquakes at Long Valley caldera, California

1995 ◽  
Vol 85 (5) ◽  
pp. 1518-1522 ◽  
Author(s):  
John R. Evans ◽  
Andrew M. Pitt
Keyword(s):  
Time Window ◽  
Poor Performance ◽  
Volcanic Hazards ◽  
Active Management ◽  
Tectonic Earthquake ◽  
Long Valley Caldera ◽  
Volcanic Earthquakes ◽  
Long Period ◽  
Long Valley ◽  
Tectonic Earthquakes

Abstract Capturing the rare long-period (LP) volcanic earthquakes occurring in and near Long Valley caldera, California, is important to ongoing volcanic-hazards monitoring. It is difficult, however, because LP events are weak, emergent, and almost devoid of energy above a few hertz. Automatic systems designed for tectonic earthquakes routinely fail to capture LP events. We applied a PC-based teleseism-specific event-detection computer program to capturing these events. Retuning the software for LP events involved only changing parameters originally designed for change in this algorithm. Our retuned algorithm has captured every known LP event at Long Valley from October 1992 through the end of 1994. We monitored up to 16 stations known to produce good records of LP events, saving those events that triggered enough of these stations (typically 10 of 16) within a specified time window. The principal difficulty has been the algorithm's sensitivity to regional earthquakes, which have waveforms similar to LP events. During our test, the 1992 Landers, 1994 Northridge, and 1994 Double Springs Flat (Nevada) earthquakes each have swamped the detector, requiring careful, active management of PC disk resources. The efficacy of this retuned algorithm and the poor performance of tectonic-earthquake detectors during some volcanic emergencies make this algorithm an attractive candidate for volcano monitoring.

On nearly-commensurable periods in the restricted problem of three bodies, with calculations of the long-period variations in the interior 2:1 case

1966 ◽  
Vol 25 ◽  
pp. 197-222 ◽  
Author(s):  
P. J. Message
Keyword(s):  
Periodic Solution ◽  
Periodic Solutions ◽  
Large Amplitude ◽  
Restricted Problem ◽  
Small Amplitude ◽  
Minor Planets ◽  
Long Period ◽  
Numerical Integrations ◽  
Period Variations ◽  
The Mean

An analytical discussion of that case of motion in the restricted problem, in which the mean motions of the infinitesimal, and smaller-massed, bodies about the larger one are nearly in the ratio of two small integers displays the existence of a series of periodic solutions which, for commensurabilities of the typep+ 1:p, includes solutions of Poincaré'sdeuxième sortewhen the commensurability is very close, and of thepremière sortewhen it is less close. A linear treatment of the long-period variations of the elements, valid for motions in which the elements remain close to a particular periodic solution of this type, shows the continuity of near-commensurable motion with other motion, and some of the properties of long-period librations of small amplitude.To extend the investigation to other types of motion near commensurability, numerical integrations of the equations for the long-period variations of the elements were carried out for the 2:1 interior case (of which the planet 108 “Hecuba” is an example) to survey those motions in which the eccentricity takes values less than 0·1. An investigation of the effect of the large amplitude perturbations near commensurability on a distribution of minor planets, which is originally uniform over mean motion, shows a “draining off” effect from the vicinity of exact commensurability of a magnitude large enough to account for the observed gap in the distribution at the 2:1 commensurability.

Discussion following the presentation by F. Deubner

1977 ◽  
Vol 36 ◽  
pp. 69-74
Keyword(s):  
List Type ◽  
The Sun ◽  
Type Number ◽  
Harmonic Motion ◽  
Locally Excited ◽  
Long Period ◽  
Coherent Wave ◽  
Short Period ◽  
Global Modes

The discussion was separated into 3 different topics according to the separation made by the reviewer between the different periods of waves observed in the sun :1) global modes (long period oscillations) with predominantly radial harmonic motion.2) modes with large coherent - wave systems but not necessarily global excitation (300 s oscillation).3) locally excited - short period waves.

The growth of mica polytypes as studied by conventional and high-resolution TEM

1983 ◽  
Vol 41 ◽  
pp. 174-177
Author(s):  
A. Baronnet ◽  
M. Amouric
Keyword(s):  
Water Pressure ◽  
Point Of View ◽  
Temperature Fields ◽  
Natural Occurrence ◽  
Growth Mechanisms ◽  
Long Period ◽  
High Resolution Tem ◽  
Layer Stacking ◽  
Experimental Works ◽  
Potential Use

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.

TEM Analysis of Long-Period Polytypes in SiC—S

1976 ◽  
Vol 34 ◽  
pp. 630-631
Author(s):  
S. Shinozaki ◽  
J. W. Sprys
Keyword(s):  
Electron Diffraction ◽  
Isothermal Annealing ◽  
Tem Analysis ◽  
Long Period ◽  
Transmission Electron ◽  
Average Grain Size ◽  
High Resolution Tem ◽  
Structural Lattice ◽  
The Stability ◽  
Continuous Curves

In reaction sintered SiC (∽ 5um average grain size), about 15% of the grains were found to have long-period structures, which were identifiable by transmission electron microscopy (TEM). In order to investigate the stability of the long-period polytypes at high temperature, crystal structures as well as microstructural changes in the long-period polytypes were analyzed as a function of time in isothermal annealing.Each polytype was analyzed by two methods: (1) Electron diffraction, and (2) Electron micrograph analysis. Fig. 1 shows microdensitometer traces of ED patterns (continuous curves) and calculated intensities (vertical lines) along 10.l row for 6H and 84R (Ramsdell notation). Intensity distributions were calculated based on the Zhdanov notation of (33) for 6H and [ (33)3 (32)2 ]3 for 84R. Because of the dynamical effect in electron diffraction, the observed intensities do not exactly coincide with those intensities obtained by structure factor calculations. Fig. 2 shows the high resolution TEM micrographs, where the striped patterns correspond to direct resolution of the structural lattice periodicities of 6H and 84R structures and the spacings shown in the figures are as expected for those structures.

Directional observation on lipid of male nectary of Lindera megaphylla hemsl. by the rapid embedding method with polyethylene glycol (PEG)

1990 ◽  
Vol 48 (3) ◽  
pp. 718-719
Author(s):  
Dai Dalin ◽  
Guo Jianmin
Keyword(s):  
Electron Microscope ◽  
Polyethylene Glycol ◽  
Chemical Reaction ◽  
Traditional Method ◽  
Osmium Tetroxide ◽  
Unsaturated Lipid ◽  
Embedding Method ◽  
Long Period ◽  
New Methods

Lipid cytochemistry has not yet advanced far at the EM level. A major problem has been the loss of lipid during dehydration and embedding. Although the adoption of glutaraldehyde and osmium tetroxide accelerate the chemical reaction of lipid and osmium tetroxide can react on the double bouds of unsaturated lipid to from the osmium black, osmium tetroxide can be reduced in saturated lipid and subsequently some of unsaturated lipid are lost during dehydration. In order to reduce the loss of lipid by traditional method, some researchers adopted a few new methods, such as the change of embedding procedure and the adoption of new embedding media, to solve the problem. In a sense, these new methods are effective. They, however, usually require a long period of preparation. In this paper, we do research on the fiora nectary strucure of lauraceae by the rapid-embedding method wwith PEG under electron microscope and attempt to find a better method to solve the problem mentioned above.

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