scholarly journals Coda wave attenuation's dependency on Lapse time and frequency in west of Iran plateau using local earthquakes

2020 ◽  
Vol 63 (4) ◽  
Author(s):  
Rouhollah Fard ◽  
Gholam Javan-Doloei ◽  
Mohsen Farrokhi ◽  
Habib Rahimi ◽  
Majid Mahood
Keyword(s):  
Coda Wave ◽  
Lapse Time ◽  
Local Earthquakes ◽  
Iran Plateau

Estimation of Coda Wave Attenuation for the National Capital Region, Delhi, India Using Local Earthquakes

2009 ◽  
Vol 166 (3) ◽  
pp. 429-449 ◽  
Author(s):  
William K. Mohanty ◽  
Rajesh Prakash ◽  
G. Suresh ◽  
A. K. Shukla ◽  
M. Yanger Walling ◽  
...  
Keyword(s):  
Wave Attenuation ◽  
Coda Wave ◽  
National Capital Region ◽  
Capital Region ◽  
Local Earthquakes ◽  
National Capital ◽  
Coda Wave Attenuation

Seismic attenuation tomography using body-wave energy normalised by the heterogeneous coda

2020 ◽  
Author(s):  
Panayiota Sketsiou ◽  
Luca De Siena ◽  
Simona Gabrielli ◽  
Ferdinando Napolitano
Keyword(s):  
Quality Factor ◽  
Wave Energy ◽  
Body Wave ◽  
Seismic Attenuation ◽  
Coda Wave ◽  
Total Quality ◽  
Lapse Time ◽  
Density Spectrum ◽  
Coda Normalization ◽  
Coda Attenuation

<p>Seismic waves lose energy during propagation in heterogeneous Earth media. Their decrease of amplitude, defined as seismic attenuation, is central in the description of seismic wave propagation. The attenuation of coherent waves can be described by the total quality factor, <em>Q</em>, and it is defined as the fractional energy lost per cycle, controlling the decay of the energy density spectrum with lapse time. The coda normalization (CN) method is a method to measure the attenuation of P- or S-waves by taking the ratio of the direct wave energy and late coda wave energy in order to remove the source and site effects from P- and S-wave spectra. One of the main assumptions of the CN method is that coda attenuation, i.e. the decay of coda energy with lapse time measured by the coda quality factor <em>Q<sub>c</sub></em> is constant. However, several studies showed that Q<sub>c</sub> is not uniform in the crust for the lapse times considered in most attenuation studies. In this work, we propose a method to overcome this assumption, measuring coda attenuation for each source-station path and evaluating the effect of different scattering regimes on the corresponding imaging. The data consists of passive waveforms from the fault network in the Pollino Area (Southern Italy) and Mount St. Helens volcano (USA).</p>

scholarly journals Lapse-time-dependent coda-wave depth sensitivity to local velocity perturbations in 3-D heterogeneous elastic media

2016 ◽  
Vol 207 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Anne Obermann ◽  
Thomas Planès ◽  
Céline Hadziioannou ◽  
Michel Campillo
Keyword(s):  
Time Dependent ◽  
Coda Wave ◽  
Elastic Media ◽  
Local Velocity ◽  
Lapse Time ◽  
Depth Sensitivity

Lapse time and frequency-dependent coda wave attenuation for Delhi and its surrounding regions

2018 ◽  
Vol 738-739 ◽  
pp. 51-63 ◽  
Author(s):  
Rabin Das ◽  
Sagarika Mukhopadhyay ◽  
Ravi Kant Singh ◽  
Pushap R. Baidya
Keyword(s):  
Wave Attenuation ◽  
Coda Wave ◽  
Lapse Time ◽  
Frequency Dependent ◽  
Coda Wave Attenuation

scholarly journals Temporal changes of seismic velocities in the San Jacinto Fault zone associated with the 2016 Mw 5.2 Borrego Springs earthquake

2019 ◽  
Vol 220 (3) ◽  
pp. 1536-1554 ◽  
Author(s):  
Hongrui Qiu ◽  
Gregor Hillers ◽  
Yehuda Ben-Zion
Keyword(s):  
Fault Zone ◽  
Temporal Changes ◽  
Coda Wave ◽  
Seismic Velocities ◽  
Rupture Directivity ◽  
Lapse Time ◽  
Near Surface ◽  
Fault Surface ◽  
San Jacinto Fault ◽  
San Jacinto Fault Zone

SUMMARY We study temporal changes of seismic velocities associated with the 10 June 2016 Mw 5.2 Borrego Springs earthquake in the San Jacinto fault zone, using nine component Green's function estimates reconstructed from daily cross correlations of ambient noise. The analysed data are recorded by stations in two dense linear arrays, at Dry Wash (DW) and Jackass Flat (JF), crossing the fault surface trace ∼3 km northwest and southeast of the event epicentre. The two arrays have 9 and 12 stations each with instrument spacing of 25–100 m. Relative velocity changes (δv/v) are estimated from arrival time changes in the daily correlation coda waveforms compared to a reference stack. The obtained array-average δv/v time-series exhibit changes associated with the Borrego Springs event, superposed with seasonal variations. The earthquake-related changes are characterized by a rapid coseismic velocity drop followed by a gradual recovery. This is consistently observed at both arrays using time- and frequency-domain δv/v analyses with data from different components in various frequency bands. Larger changes at lower frequencies imply that the variations are not limited to the near surface material. A decreasing coseismic velocity reduction with coda wave lapse time indicates larger coseismic structural perturbations in the fault zone and near-fault environment compared to the surrounding rock. Observed larger changes at the DW array compared to the JF array possibly reflect the northwestward rupture directivity of the Borrego Springs earthquake.

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