Lateral Variations of Lg Coda Q in Southern Mexico

1997 ◽  
Vol 149 (3) ◽  
pp. 575-599 ◽  
Author(s):  
J. Yamamoto ◽  
L. Quintanar ◽  
R.B. Herrmann ◽  
C. Fuentes
Keyword(s):  
Coda Q ◽  
Southern Mexico ◽  
Lg Coda ◽  
Lateral Variations

scholarly journals Lg-coda Q in the central part of the East European platform from small aperture array “Mikhnevo” data

2019 ◽  
Vol 1 (1) ◽  
pp. 57-66
Keyword(s):  
East European Platform ◽  
Seismic Attenuation ◽  
Tectonic Activity ◽  
Q Factor ◽  
Coda Q ◽  
Small Aperture ◽  
East European ◽  
Short Period ◽  
Lg Coda ◽  
Aperture Array

Whereas the quality factor Q is one of the basic parameters required in seismic hazard estimation, no systematic studies of seismic attenuation factors have been carried out in the central part of the East European Platform due to the lack of a dense seismic network and a small number of regional earthquakes. The main part of the events, recorded by the small aperture array “Mikhnevo” 80 km to the south of Moscow, consists of industrial explosions of different magnitude. The idea of the paper is to apply conventional seismic methods to the analysis of seismic waveforms of industrial explosions. The paper focuses on the Lg coda of the quarry blast in “Mikhailovsky” quarry 300 km from the array. Vertical components of the short-period and broad band records of the sensors positioned in the well at the depth 20 m are processed according to the SSR algorithm, suggested by Xie and Nuttli, 1988, and extensively used by Mitchell et al in different regions of the world. The advantages of the method imply exclusion of the source and site characteristics by taking spectral ratios of the successive time windows of the coda. Compared to the earthquake waveforms, the Lg coda of explosions is shorter, less regular and contains higher frequencies. The length of coda varies according to the noise level. We selected 14 events from the same quarry in different years, which demonstrate remarkable stability of the waveforms. All the events were processed individually to obtain the frequency dependence of Q in the form Q(f)=Q0 f , where Q0 is the Q factor at the frequency 1 Hz and  is the power. To produce stable estimates of Q0 and  individual values were averaged for frequency bands: 2-6 Hz, 2-7 Hz, 3-6 Hz, 3-7 Hz for different length of coda. The preferable frequency range for Lg coda Q studies of quarry blasts is suggested as 3-6 Hz, which avoids instability of coda in 1-3 Hz interval, presumably caused by local site effect, connected with the 3 km thick sedimentary layer. The Q estimate of Q0=584±89, =0.41±0.06 proves considerable heterogeneity of the upper crust in the region. Speaking about Q factor as an indicator of the tectonic activity, the studied area can be related to a region of moderate activity.

mb(LgCoda): A stable single station estimator of magnitude

1993 ◽  
Vol 83 (3) ◽  
pp. 851-861 ◽  
Author(s):  
Kevin Mayeda
Keyword(s):  
Water Table ◽  
Source Region ◽  
Test Site ◽  
Strongly Correlated ◽  
Nevada Test Site ◽  
Nuclear Explosions ◽  
Empirical Relations ◽  
Single Station ◽  
Lg Coda ◽  
Lateral Variations

Abstract Stable single-station estimates of magnitude have been made using the 1-Hz Lg coda envelope of regionally recorded nuclear explosions from the Nevada Test Site (NTS). After empirical relations describing the Lg coda envelope were found for each NTS-station path, single station magnitudes based on the Lg coda envelope were made with precision in the range of 0.03 to 0.04 magnitude units, whereas magnitudes based on third peak Lg amplitude, rms Lg amplitude, and Pn amplitude had scatter on the order of 0.15 to 0.2 magnitude units, generally five times larger than the coda scatter. Despite the high station correlations, the magnitude-yield residuals for events above the water table using the network average mb(LgCoda) were only marginally better than the other magnitude estimates, roughly 10% smaller. Magnitude-yield residual for events above the water table between mb(LgCoda) and mb(Lg) are strongly correlated suggesting that the source region properties, such as gas porosity, affect both magnitudes. Using only a single station, the standard deviation for magnitude-yield residuals using mb(LgCoda) were roughly 25% smaller than those derived from mb(Lg) or mb(Pn). These results show that the method is ideally suited to monitoring efforts in sparsely instrumented regions where little is known about the lateral variations of medium properties.

Distribution of Lg coda Q in the Chinese continent and its adjacent regions

2003 ◽  
Vol 46 (6) ◽  
pp. 540 ◽  
Author(s):  
Liandeng LIU
Keyword(s):  
Coda Q ◽  
Chinese Continent ◽  
Lg Coda

Distribution of Lg coda Q in the Chinese continent and its adjacent regions

2003 ◽  
Vol 46 (6) ◽  
pp. 529 ◽  
Author(s):  
Lianli CONG
Keyword(s):  
Coda Q ◽  
Chinese Continent ◽  
Lg Coda

Lg Coda Q in Australia and its Relation to Crustal Structure and Evolution

1998 ◽  
Vol 153 (2-4) ◽  
pp. 639-653 ◽  
Author(s):  
B. J. Mitchell ◽  
S. Baqer ◽  
A. Akinci ◽  
L. Cong
Keyword(s):  
Crustal Structure ◽  
Coda Q ◽  
Lg Coda

Lg Coda Q Variations across South America and their Relation to Crustal Evolution

1998 ◽  
pp. 587-612
Author(s):  
J. L. de Souza ◽  
B. J. Mitchell
Keyword(s):  
South America ◽  
Crustal Evolution ◽  
Coda Q ◽  
Lg Coda

Lg coda Q 0 value and its relation with the tectonics in chinese mainland and adjacent regions

2006 ◽  
Vol 19 (2) ◽  
pp. 136-144
Author(s):  
Wei Su ◽  
Jiang-ping Wu ◽  
Yue-hong Ming ◽  
Chun-yong Wang
Keyword(s):  
Chinese Mainland ◽  
Coda Q ◽  
Lg Coda

Estimation of seismodynamics differences and lateral variations of coda Q in Eastern Anatolia

2014 ◽  
Vol 8 (8) ◽  
pp. 6363-6370 ◽  
Author(s):  
Ufuk Aydın
Keyword(s):  
Eastern Anatolia ◽  
Coda Q ◽  
Lateral Variations
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