Landslide Characteristics Revealed by High-Frequency Seismic Waves from the 2017 Landslide in Central Japan

2020 ◽  
Vol 91 (5) ◽  
pp. 2719-2729
Author(s):  
Issei Doi ◽  
Takuto Maeda
Keyword(s):  
High Frequency ◽  
Seismic Waves ◽  
Wave Packets ◽  
Impulsive Phase ◽  
Frequency Component ◽  
Source Location ◽  
High Frequency Component ◽  
Central Japan ◽  
Location Determination ◽  
High Frequency Seismic Waves

Abstract The recent development of advanced seismograph networks offers us a chance to remotely detect landslide occurrences with high-frequency (>∼1  Hz) components. This study examined a landslide in central Japan that produced clearly detectable seismic signals at multiple seismic stations in a permanent network. Wave packets propagated with a group velocity of 3  km/s from the landslide area. Using a source location determination method with amplitude information from the high-frequency component, the source location of the wave packets was shown to be in the vicinity of the landslide with an error of 5 km. Moreover, seismograms specific to this landslide also contained a distinct impulsive phase with a source located in the vicinity of the landslide. The study demonstrated that seismic waves with a high-frequency component from landslides can be used to estimate their mechanisms as well as their locations when they are recognized by a routine seismic network.

Vibroseis Nonlinear Scanning Signal Simulation Analysis

2013 ◽  
Vol 318 ◽  
pp. 191-195
Author(s):  
Gong Ming Zheng ◽  
Yuan Yuan Shen ◽  
Ling Ling Song
Keyword(s):  
High Frequency ◽  
Seismic Waves ◽  
Simulation Analysis ◽  
Frequency Component ◽  
Seismic Exploration ◽  
High Frequency Component ◽  
Frequency Components ◽  
Signal Simulation ◽  
Important Means ◽  
Filtering Effect

Vibrator nonlinear scan is an important means of high frequency seismic exploration. With the propagation of seismic waves, High frequency components continue to be absorbed, due to the filtering effect of the earth. Nonlinear scanning technology can get some degree of compensation to the seismic wave loss in the high frequency part in the propagation, by extending the vibration of the high frequency component time. This article through MATLAB simulation, this paper analyzed the nonlinear scanning signals in scanning signals and logarithmic index scanning signals, and the similarities and differences between the two signals are summarized.

Laser-Generated Ultrasonic Technique for Inspecting Delamination in CFRP

2006 ◽  
Vol 321-323 ◽  
pp. 968-971
Author(s):  
Won Su Park ◽  
Sang Woo Choi ◽  
Joon Hyun Lee ◽  
Kyeong Cheol Seo ◽  
Joon Hyung Byun
Keyword(s):  
High Frequency ◽  
Ultrasonic Method ◽  
Piezoelectric Sensor ◽  
Frequency Component ◽  
Guided Wave ◽  
Center Frequency ◽  
High Frequency Component ◽  
Ultrasonic Technique ◽  
Non Destructive Evaluation ◽  
Non Destructive

For improving quality of a carbon fiber reinforced composite material (CFRP) by preventing defects such as delamination and void, it should be inspected in fabrication process. Novel non-contacting evaluation technique is required because the transducer should be contacted on the CFRP in conventional ultrasonic technique during the non-destructive evaluation and these conventional contact techniques can not be applied in a novel fiber placement system. For the non-destructive evaluation of delamination in CFRP, various methods for the generation and reception of laser-generated ultrasound are applied using piezoelectric transducer, air-coupled transducer, wavelet transform technique etc. The high frequency component of laser-generated guided wave received with piezoelectric sensor disappeared after propagating through delamination region. Air-coupled transducer was tried to be adopted in reception of laser-generated guided wave generated by using linear slit array in order to generate high frequency guided wave with a frequency of 1.1 MHz. Nevertheless, it was failed to receive high frequency guided wave in using air-coupled transducer and linear slit array. Transmitted laser-generated ultrasonic wave was received on back-wall and its frequency was analyzed to establish inspecting technique to detect delamination by non-contact ultrasonic method. In a frequency spectrum analysis, intensity ratio of low frequency and center frequency was approvable parameter to detect delamination.

High frequency seismic waves and slab structures beneath Italy

2014 ◽  
Vol 391 ◽  
pp. 212-223 ◽  
Author(s):  
Daoyuan Sun ◽  
Meghan S. Miller ◽  
Nicola Piana Agostinetti ◽  
Paul D. Asimow ◽  
Dunzhu Li
Keyword(s):  
High Frequency ◽  
Seismic Waves ◽  
High Frequency Seismic Waves

Hierarchal Predefined Codebook for High-Frequency Component Augmentation Image Enlargement

2010 ◽  
Author(s):  
Hakaru Tamukoh ◽  
Hideaki Kawano ◽  
Noriaki Suetake ◽  
Masatoshi Sekine ◽  
Byungki Cha ◽  
...  
Keyword(s):  
High Frequency ◽  
Frequency Component ◽  
High Frequency Component ◽  
Image Enlargement
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