scholarly journals Temporal Variations of Seismic Velocity at Paradox Valley, Colorado, Using Passive Image Interferometry

2014 ◽  
Vol 104 (3) ◽  
pp. 1088-1099 ◽  
Author(s):  
A. Ugalde ◽  
B. Gaite ◽  
A. Villasenor
Keyword(s):  
Seismic Velocity ◽  
Temporal Variations ◽  
Passive Image Interferometry

scholarly journals Comprehensive observation and modeling of earthquake and temperature-related seismic velocity changes in northern Chile with passive image interferometry

2014 ◽  
Vol 119 (6) ◽  
pp. 4747-4765 ◽  
Author(s):  
Tom Richter ◽  
Christoph Sens-Schönfelder ◽  
Rainer Kind ◽  
Günter Asch
Keyword(s):  
Seismic Velocity ◽  
Northern Chile ◽  
Seismic Velocity Changes ◽  
Velocity Changes ◽  
Passive Image Interferometry

scholarly journals Evidence of reactivation of a hydrothermal system from seismic anisotropy changes

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Maria Saade ◽  
Kohtaro Araragi ◽  
Jean Paul Montagner ◽  
Edouard Kaminski ◽  
Philippe Roux ◽  
...  
Keyword(s):  
Seismic Anisotropy ◽  
Seismic Velocity ◽  
Temporal Variations ◽  
Volcanic Area ◽  
Velocity Measurements ◽  
Noise Interferometry ◽  
Volcanic Monitoring ◽  
Monitoring And Forecasting ◽  
Active Processes ◽  
Insight Into

AbstractSeismic velocity measurements have revealed that the Tohoku-Oki earthquake affected velocity structures of volcanic zones far from the epicenter. Using a seismological method based on ambient seismic noise interferometry, we monitored the anisotropy in the Mount Fuji area during the year 2011, in which the Tohoku-Oki earthquake occurred (Mw = 9.0). Here we show that even at 400 km from the epicenter, temporal variations of seismic anisotropy were observed. These variations can be explained by changes in the alignment of cracks or fluid inclusions beneath the volcanic area due to stress perturbations and the propagation of a hydrothermal fluid surge beneath the Hakone hydrothermal volcanic area. Our results demonstrate how a better understanding of the origin of anisotropy and its temporal changes beneath volcanoes and in the crust can provide insight into active processes, and can be used as part of a suite of volcanic monitoring and forecasting tools.

Measurement of seawater average velocity using water bottom multiples from vertical seismic profile surveys

2016 ◽  
Vol 4 (4) ◽  
pp. SQ13-SQ22 ◽  
Author(s):  
Yingping Li ◽  
Ben Hewett
Keyword(s):  
Average Velocity ◽  
Seismic Velocity ◽  
Autonomous Underwater Vehicles ◽  
Time Lapse ◽  
Seismic Profile ◽  
Temporal Variations ◽  
Vertical Seismic Profile ◽  
Velocity Models ◽  
Vsp Data ◽  
Water Bottom

Previous diagnoses of surface seismic velocity models with vertical seismic profile (VSP) data in the Gulf of Mexico have indicated that shallow velocities were poorly constrained by VSP due to ringing caused by multiple casing strings. This ringing also hampered direct measurement of the seawater average velocity (SWAV) at a rig site with direct arrivals of a zero-offset VSP (ZVSP). We have directly measured the SWAV at a rig site with a known water depth by using differential times between primary water bottom multiples (WBMs) and direct first arrivals acquired in a marine VSP survey. We developed a procedure to process ZVSP-WBM signals for SWAV measurement. This WBM method is successfully applied to VSP data recorded at 27 rig sites in the deep-water environments of North and South America. Our results suggest that VSP processors should implement this method and add the SWAV measurement in their future velocity survey reports. We have estimated water bottom depths using differential times. We found that the estimated water depths are comparable with those acquired from sonar measurements by autonomous underwater vehicles, but with large uncertainties. The WBM method is extended by using data from a vertical incidence VSP to measure a profile of the SWAV along the path of a deviated well and evaluate possible lateral variations of SWAV. This method can potentially be applied to a time-lapse VSP to monitor temporal variations of SWAV. We also evaluated the application scope and limitations of the WBM method.

scholarly journals Exploring the Rheology of a Seismogenic Zone by Applying Seismic Variation

2021 ◽  
Vol 11 (19) ◽  
pp. 8847
Author(s):  
Chun-Fu Liao ◽  
Strong Wen ◽  
Chau-Huei Chen ◽  
Ying-Nien Chen
Keyword(s):  
Velocity Structure ◽  
Seismic Velocity ◽  
Hanging Wall ◽  
Source Area ◽  
Temporal Variations ◽  
Spatiotemporal Variation ◽  
Seismogenic Zone ◽  
Time Data ◽  
Junctional Zone ◽  
Chelungpu Fault

Although the study of spatiotemporal variation of a subsurface velocity structure is a challenging task, it can provide a description of the fault geometry as well as important information on the rheological changes caused by fault rupture. Our main objective is to investigate whether rheological changes of faults can be associated with the seismogenic process before a strong earthquake. For this purpose, a 3D tomographic technique is applied to obtain P- and S-wave velocity structures in central Taiwan using travel time data. The results show that temporal variations in the Vs structure in the source area demonstrate significant spatiotemporal variation before and after the Chi-Chi earthquake. We infer that, before the mainshock, Vs began to decrease (and Vp/Vs increased) at the hanging wall of the Chelungpu fault, which may be induced by the increasing density of microcracks and fluid. However, in the vicinity of the Chi-Chi earthquake’s source area, Vs increased (and Vp/Vs decreased), which may be attributed to the closing of cracks or migration of fluid. The different physical characteristics at the junctional zone may easily generate strong earthquakes. Therefore, seismic velocity changes are found to be associated with a subsurface evolution around the source area in Taiwan. Our findings suggest that monitoring the Vp and Vs (or Vp/Vs) structures in high seismic potential zones is an important ongoing task, which may minimize the damage caused by future large earthquakes.

scholarly journals Continuous monitoring system for safe managements of CO2 storage and geothermal reservoirs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takeshi Tsuji ◽  
Tatsunori Ikeda ◽  
Ryosuke Matsuura ◽  
Kota Mukumoto ◽  
Fernando Lawrens Hutapea ◽  
...  
Keyword(s):  
Monitoring System ◽  
Continuous Monitoring ◽  
Field Experiments ◽  
Seismic Velocity ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Co2 Storage ◽  
Seismic Source ◽  
Temporal Variations ◽  
Wide Frequency Range

AbstractWe have developed a new continuous monitoring system based on small seismic sources and distributed acoustic sensing (DAS). The source system generates continuous waveforms with a wide frequency range. Because the signal timing is accurately controlled, stacking the continuous waveforms enhances the signal-to-noise ratio, allowing the use of a small seismic source to monitor extensive areas (multi-reservoir). Our field experiments demonstrated that the monitoring signal was detected at a distance of ~ 80 km, and temporal variations of the monitoring signal (i.e., seismic velocity) were identified with an error of < 0.01%. Through the monitoring, we identified pore pressure variations due to geothermal operations and rains. When we used seafloor cable for DAS measurements, we identified the monitoring signals at > 10 km far from the source in high-spatial resolution. This study demonstrates that multi-reservoir in an extensive area can be continuously monitored at a relatively low cost by combining our seismic source and DAS.

Revealing seasonal crustal seismic velocity variations in Taiwan with single-station cross-component analysis 

2021 ◽  
Author(s):  
Kuan-Fu Feng ◽  
Hsin-Hua Huang ◽  
Ya-Ju Hsu ◽  
Yih-Min Wu
Keyword(s):  
Pore Pressure ◽  
Seasonal Variations ◽  
Seismic Velocity ◽  
Pressure Change ◽  
Temporal Variations ◽  
Air Pressure ◽  
Weather Data ◽  
Single Station ◽  
Seismic Velocity Changes ◽  
Velocity Changes

&lt;p&gt;Ambient noise interferometry is a promising technique for studying crustal behaviors, providing continuous measurements of seismic velocity changes (dv/v) in relation to physical processes in the crust over time. In addition to the tectonic-driven dv/v changes, dv/v is also known to be affected by environmental factors through rainfall-induced pore-pressure changes, air pressure loading changes, thermoelastic effects, and so forth. In this study, benefiting from the long-term continuous data of Broadband Array in Taiwan for Seismology (BATS) that has been operated since 1994, we analyze continuous seismic data from 1998 to 2019 by applying single-station cross-component (SC) technique to investigate the temporal variations of crust on seismic velocity. We process the continuous waveforms of BATS stations, construct the empirical Green&amp;#8217;s functions, and compute daily seismic velocity changes by the stretching technique in a frequency band of 0.1 to 0.9 Hz. We observe co-seismic velocity drops associated with the inland moderate earthquakes. Furthermore, clear seasonal cycles, with a period of near one-year, are also revealed at most stations, but with different characteristics. Systematic spectral and time-series analyses with the weather data are conducted and show that the rainfall-induced pore-pressure change is likely the main cause to the seasonal variations with high correlations. The strong site-dependency of these seasonal variations also precludes air pressure and temperature which varies smoothly in space from being dominant sources and suggests spatially-varying complex hydro-mechanical interaction across the orogenic belt in Taiwan.&lt;/p&gt;

Temporal and spatial variations of travel-time residuals in central California for Novaya Zemlya events

1976 ◽  
Vol 66 (5) ◽  
pp. 1733-1747 ◽  
Author(s):  
Russell Robinson ◽  
H. M. Iyer
Keyword(s):  
Travel Time ◽  
Seismic Velocity ◽  
Temporal Variations ◽  
P Wave ◽  
Central California ◽  
Nuclear Explosions ◽  
Novaya Zemlya ◽  
San Andreas ◽  
Temporal And Spatial

abstract Eight large nuclear explosions in Novaya Zemlya, from October 1969, through November 1974, were used to monitor long-term variations in crustal seismic velocity near the San Andreas fault in central California. Relative P-wave travel-time residuals appear to be accurate to approximately ±0.1 sec. Of the over 100 stations used, none show clearly significant temporal variations in residual greater than this amount, corresponding to about a 4 per cent change in velocity in the upper crust. Average relative residuals at individual stations show a large spatial variation of about 1.5 sec. These variations reflect both a complex crustal geology and changes in crustal thickness and provide a potentially powerful tool for studying crustal structure.

scholarly journals Continuous monitoring system for safe managements of CO2 storage and geothermal reservoirs

2021 ◽  
Author(s):  
Takeshi Tsuji ◽  
Tatsunori Ikeda ◽  
Ryosuke Matsuura ◽  
Kota Mukumoto ◽  
Hutapea Lawrens ◽  
...  
Keyword(s):  
Monitoring System ◽  
Continuous Monitoring ◽  
Field Experiments ◽  
Seismic Velocity ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Co2 Storage ◽  
Seismic Source ◽  
Temporal Variations ◽  
Wide Frequency Range

Abstract We have developed a new continuous monitoring system based on small seismic sources and distributed acoustic sensing (DAS). The source system generates continuous waveforms with a wide frequency range. Because the signal timing is accurately controlled, stacking continuous waveforms enhances the signal-to-noise ratio, allowing the use of a small seismic source to monitor extensive areas (multi-reservoir). Our field experiments demonstrated that the monitoring signal was detected at a distance of ~80 km, and temporal variations of the monitoring signal (i.e., seismic velocity) were identified with >99.9% accuracy. Through the monitoring, we identified pore pressure variations due to geothermal operations and rains. When we used seafloor cable for DAS measurements, we identified the monitoring signals at >10 km far from the source in high-spatial resolution. This study demonstrates that multi-reservoir in an extensive area can be continuously monitored at a relatively low cost by combining our seismic source and DAS technology.

scholarly journals Erratum toTemporal Variations of Seismic Velocity at Paradox Valley, Colorado, Using Passive Image Interferometry

2016 ◽  
Vol 106 (2) ◽  
pp. 812-812
Author(s):  
Arantza Ugalde ◽  
Beatriz Gaite ◽  
Antonio Villaseñor
Keyword(s):  
Seismic Velocity ◽  
Passive Image Interferometry

Coseismic and post-seismic velocity changes detected by Passive Image Interferometry: comparison of one great and five strong earthquakes in Japan

2016 ◽  
Vol 205 (2) ◽  
pp. 1053-1073 ◽  
Author(s):  
Manuel Hobiger ◽  
Ulrich Wegler ◽  
Katsuhiko Shiomi ◽  
Hisashi Nakahara
Keyword(s):  
Seismic Velocity ◽  
Strong Earthquakes ◽  
Seismic Velocity Changes ◽  
Velocity Changes ◽  
Passive Image Interferometry
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