scholarly journals The 2002–2005 Changbaishan Volcanic Unrest Triggered by the 2002 M 7.2 Wangqing Deep Focus Earthquake

2021 ◽  
Vol 8 ◽  
Author(s):  
Guoming Liu ◽  
Chenyu Li ◽  
Zhigang Peng ◽  
Yinan Liu ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Template Matching ◽  
Physical Mechanism ◽  
Earthquake Swarm ◽  
Shallow Magma Chamber ◽  
Distant Interaction ◽  
Changbaishan Volcano ◽  
Matching Technique ◽  
Different Types ◽  
Deep Focus ◽  
Magma System

One of the most active intraplate volcanoes in East Asia, Changbaishan volcano experienced unrest from July 2002 to July 2005. On 2002/06/28, the M 7.2 Wangqing deep-focus earthquake occurred ∼290 km northeast of Changbaishan volcano. While some studies have suggested a possible triggering relationship, the physical mechanism of such distant interaction is still not well understood. Using a template matching technique, which cross-correlates waveform of known events with continuous data, we perform systematic detection of microseismic events recorded by station CBS near Changbaishan volcano from July 1999 to July 2007. The detected earthquakes can be further categorized into three different types: volcano-tectonic (VT) events, long-period (LP) events and harmonic-spectra (HS) events. We detect 3763 VT events between July 2002 and July 2007. The intense VT earthquake swarm during the period from July 2002 to July 2005, along with recurring LPs and HSs and other geodetic/geochemical evidence, suggest magma movement during unrest. Compared with the hand-picked catalogue, the catalogue obtained by template matching technique reveals a delayed-triggering relationship between Wangqing deep-focus earthquake and unrest. The small magnitudes of the VT events and the limited numbers of LP and HS events suggest that the Wangqing mainshock likely triggered bubble excitation in the mid-crust magma system, resulting in overpressure and a small magma injection into the shallow magma chamber at a depth of ∼5 km, leading to the 3-years unrest.

A Method to Extract Essential Information from Meteorological Facsimile Charts

2018 ◽  
Vol 33 (01) ◽  
pp. 1954001
Author(s):  
Kefeng Mao ◽  
Xi Chen ◽  
Kelan Zhu ◽  
Dong Hu ◽  
Yan Li
Keyword(s):  
Template Matching ◽  
Weather Forecasting ◽  
Contour Detection ◽  
Connected Region ◽  
Good Effect ◽  
Weather System ◽  
Essential Information ◽  
The Us ◽  
Different Types ◽  
Other Information

Using image processing technology to extract important information, such as isoline and weather system of the meteorological facsimile chart, is conducive to integration with other information, and has important practical value in navigation operations, marine weather forecasting, target recognition, and image retrieval. In meteorological facsimile charts, there are many types of medium-value lines, dense lines in some areas, superimposition and presence of multiple information, such as isolines and isoline characters, intersection of specific weather system symbols, etc. For different types of contours, numeric characters, weather system symbols and other object characteristics, the corresponding object extraction and recognition methods are proposed: Remove the latitude and longitude lines and coastline in the meteorological facsimile map by basemap matching; According to the position and shape features of the figure box, extract the meteorological fax figure box, separate and remove the different character tagging information; On the basis of identifying triangles and semicircles in weather symbols of the frontal system, the frontal symbols are extracted based on the circumscribed triangles and template matching. First the contour character on the fax image is expanded into a block connected region. Determine the position of the character information by judging the number of pixels in the connected region, and then use rotation and template matching to identify the numeric character. Using the meteorological facsimile maps of the US Meteorological Center and the Japan Meteorological Center for the main information extraction, experiments show that the method of this paper has a good effect on the complete and accurate symbol extraction of frontal weather systems, and reduces the computational complexity of contour detection, isoline extraction and numerical recognition. The methods can detect some information from weather charts properly and the error rate is very low.

scholarly journals Hierarchical Region Based Template Matching Technique for Global Motion Reduction of Coronary Cineangiograms

2015 ◽  
Vol 7 (2) ◽  
pp. 156-161 ◽  
Author(s):  
Kulathilake K. A. S. H. ◽  
Ranathunga L. ◽  
Constantine G. R. ◽  
Abdullah N. A.
Keyword(s):  
Template Matching ◽  
Global Motion ◽  
Matching Technique

Spectral yield estimation of NTS explosions

1991 ◽  
Vol 81 (4) ◽  
pp. 1292-1308
Author(s):  
Steven R. Taylor ◽  
Farid U. Dowla
Keyword(s):  
Shock Wave ◽  
Template Matching ◽  
Spectral Shape ◽  
Source Material ◽  
Matching Function ◽  
Spectral Matching ◽  
Matching Technique ◽  
Regression Techniques ◽  
The Difference ◽  
Unknown Event

Abstract The yields of 299 NTS explosions have been estimated from Pn, Pg and Lg spectra (between 0.1 and 10 Hz) at four regional seismic stations. A spectral template matching technique is used where the spectra from an explosion of unknown yield are compared with the spectra of explosions of known yield. A matching function is defined that is a scaled inverse of the difference between the spectra from the known and unknown explosions. The yields from the seven closest matching explosions are then averaged to estimate the yield of the unknown event. The spectral matching technique appears to perform as well as standard regression techniques utilizing mb(Pn) and mb(Lg) measurements except that no geologic information (such as gas-filled porosity) is required. However, the spectral matching technique is only applicable to very well-calibrated test sites. The key to spectral matching is that the spectral shape is sensitive to the near-source geology. In addition to affecting the absolute spectral levels (i.e., coupling), the dynamic response of the near source material to the radiated shock wave is a major factor controlling the shape of the radiated spectra. The spectral shape can therefore be used as an indicator for predicting the coupling of an explosion, which can be subsequently used to predict its yield.

scholarly journals Initial effective stress controls the nature of earthquakes

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
François X. Passelègue ◽  
Michelle Almakari ◽  
Pierre Dublanchet ◽  
Fabian Barras ◽  
Jérôme Fortin ◽  
...  
Keyword(s):  
Effective Stress ◽  
Physical Mechanism ◽  
Fluid Pressure ◽  
Fault Slip ◽  
Rupture Velocity ◽  
Complete Spectrum ◽  
Available Energy ◽  
Different Types ◽  
Theoretical Predictions ◽  
Shallow Part

Abstract Modern geophysics highlights that the slip behaviour response of faults is variable in space and time and can result in slow or fast ruptures. However, the origin of this variation of the rupture velocity in nature as well as the physics behind it is still debated. Here, we first highlight how the different types of fault slip observed in nature appear to stem from the same physical mechanism. Second, we reproduce at the scale of the laboratory the complete spectrum of rupture velocities observed in nature. Our results show that the rupture velocity can range from a few millimetres to kilometres per second, depending on the available energy at the onset of slip, in agreement with theoretical predictions. This combined set of observations bring a new explanation of the dominance of slow rupture fronts in the shallow part of the crust or in areas suspected to present large fluid pressure.

scholarly journals Review and Mechanism of the Thickness Effect of Solid Dielectrics

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2473
Author(s):  
Liang Zhao ◽  
Chun Liang Liu
Keyword(s):  
Physical Mechanism ◽  
Breakdown Strength ◽  
Power Relation ◽  
Thickness Effect ◽  
Power Exponent ◽  
Relative Standard Error ◽  
Dielectric Thickness ◽  
Relative Standard ◽  
Different Types ◽  
Solid Dielectrics

The thickness effect of solid dielectrics means the relation between the electric breakdown strength (EBD) and the dielectric thickness (d). By reviewing different types of expressions of EBD on d, it is found that the minus power relation (EBD = E1d−a) is supported by plenty of experimental results. The physical mechanism responsible for the minus power relation of the thickness effect is reviewed and improved. In addition, it is found that the physical meaning of the power exponent a is approximately the relative standard error of the EBD distributions in perspective of the Weibull distribution. In the end, the factors influencing the power exponent a are discussed.

Development of a multiple-template matching technique for removal of false positives in a computer-aided diagnostic scheme

2001 ◽  
Author(s):  
Qiang Li ◽  
Shigehiko Katsuragawa ◽  
Roger M. Engelmann ◽  
Samuel G. Armato III ◽  
Heber MacMahon ◽  
...  
Keyword(s):  
Template Matching ◽  
False Positives ◽  
Computer Aided ◽  
Matching Technique ◽  
Multiple Template
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