Evidence of low Q below Popocatépetl Volcano, and its implication to seismic hazard in Mexico City

Shapiro, N. M.; Singh, S. K.; Iglesias-Mendoza, Arturo; Cruz‐Atienza, V. M.; Pacheco, Jesús

doi:10.1029/1999gl011232

Cited by 32 publications

(16 citation statements)

References 7 publications

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“…Figure 12 shows that the difference in Q Lg compared with adjacent regions is more pronounced at higher frequencies. This result is similar to that reported by Shapiro et al [2000]. The strong attenuation at higher frequencies in the volcanic zone is probably caused by heating or partial melting of the crustal material and/or by the enhanced scattering caused by the higher level of small-scale heterogeneities due to the active tectonic processes in the volcanic zone.…”

supporting

confidence: 81%

Lateral variation of Lg wave propagation in southern Mexico

et al. 2002

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[1] In this study we investigated lateral variation of Lg wave propagation in southern Mexico from recordings of 92 crustal earthquakes along 591 travel paths. The efficiency of Lg propagation was measured in terms of Lg to Pn spectral ratio. It was found that Lg propagation is inefficient for travel paths through the Gulf of Mexico coastal plains and the Gulf of Tehuantepec, areas with thick layers of sediments. An average Lg quality factor, Q Lg , as a function of frequency for southern Mexico was estimated for the efficient Lg travel paths. The relation obtained for Q Lg in the frequency range 1.6-8 Hz is Q Lg ( f ) = 204 f 0.85 . The lateral variation of Q Lg À1 was solved as a mixeddetermined inverse tomography problem, separately for each frequency, in which a spatial smoothness constraint was imposed and a priori information was added in poorly covered regions. The spatial resolution obtained was about 200 km. It was found that the Trans-Mexican Volcanic Belt, the Gulf of Mexico coastal plains, and the area east of 94°W are characterized by lower than average Q Lg values, i.e., higher attenuation. High Q Lg values were obtained for the Mixteco-Oaxaca terranes, while for the Guerrero terrane, values similar to the average were obtained. The results show a correlation between Q Lg and crustal structure and provide valuable information on lateral variation of Q Lg , which is needed for reliable prediction of ground motion during future earthquakes.

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confidence: 81%

Lateral variation of Lg wave propagation in southern Mexico

et al. 2002

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“…Malagnini et al (2000a) studied the regional attenuation along the Apennines and found an anelastic attenuation of Q (f ) ‫ס‬ 130f 0.10 combined with a geometrical spreading: r ‫9.0מ‬ for r Յ 30 km, r 0 for 30 km Յ r Յ 80 km, and r ‫5.0מ‬ for r Ն 80 km. The values found for Mexico and the Apennines may be typical of active regions and are probably related to the presence of fluids in the rocks or highly fractured zones; this high attenuation also may be attributed to partial melting of rocks, or the presence of magma around the Popocatépetl volcano (Shapiro et al, 2000). Stable regions, as the New Madrid zone in the central United States, are characterized by slow deformation of the crust and show lower attenuation.…”

Section: Propagation Termmentioning

confidence: 96%

Earthquake Ground-Motion Scaling in Central Mexico between 0.7 and 7 Hz

Ortega¹,

Herrmann²,

Quintanar³

2003

Bulletin of the Seismological Society of America

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We present results from a regional study of ground-motion scaling parameters in central Mexico using data from a short-period vertical-component network and two broadband stations within the valley of Mexico. A total of 1220 waveforms recorded between 1994 and 2001 are used for the analysis. A damped least-squares regression using a simple model to separate the excitation, site, and propagation effects for the peak velocities in selected narrow-bandpass frequencies was carried out. The propagation term was parameterized to define a piecewise continuous geometrical spreading function, a frequency-dependent Q (f ), and a distancedependent duration that are consistent with the random vibration theory. We measured the average attenuation of S and Lg waves. A final model with a quality factor of Q(f ) ‫ס‬ 180f 0.66 and a geometrical spreading of

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“…For the sites situated just beyond the Colima Volcanic Complex, the observed intensities of the earthquake were slightly diminished compared with other sites situated at the same distance from the epicenter. This similar effect, of increasing attenuation in the energy of seismic waves passing beneath a active volcanic complex, has also been noted for other volcanoes (e.g., Shapiro et al, 2000). Figure 7 demonstrates that during the earthquake the intensities of VII were observed almost exclusively within the state of Colima.…”

Section: Macroseismic Pattern Of the 2003 Colima Earthquakementioning

confidence: 59%

Macroseismic Study of the Mw 7.5 21 January 2003 Colima, Mexico, Across-Trench Earthquake

Zobin¹,

Pizano-Silva²

2007

Bulletin of the Seismological Society of America

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A field investigation of residential house damage in 83 localities of the Occidental part of México allowed construction of a macroseismic map of the moment magnitude 7.5 2003 Colima earthquake. The 12-grade modified Mercalli (MM) scale and the 7-grade damage scale of Whitman (1988) were used for estimating the earthquake intensities. The macroseismic effects of this earthquake were unexpected for the Occidental part of México. The earthquake occurred within the across-trench structure of the El Gordo Graben and was characterized by the down-dip acrosstrench directivity of its rupture, as reconstructed from seismic-waveform modeling. It was a reason for the severe damage to buildings in the localities situated at distances where usual along-trench rupturing subduction earthquakes of the same magnitude do not produce any significant damage. The macroseismic map of the 2003 earthquake shows that the narrow (30 km wide) MM VII zone was elongated (up to 60 km) in the northeast direction toward the continental part of Colima state. As a result, the intensity in Colima city was 1.5 grades larger than would be expected for this magnitude according to the proposed attenuation of intensity with distance relationship for earthquakes from the Mexican subduction zone.

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Evidence of low Q below Popocatépetl Volcano, and its implication to seismic hazard in Mexico City

Cited by 32 publications

References 7 publications

Lateral variation of Lg wave propagation in southern Mexico

Lateral variation of Lg wave propagation in southern Mexico

Earthquake Ground-Motion Scaling in Central Mexico between 0.7 and 7 Hz

Macroseismic Study of the Mw 7.5 21 January 2003 Colima, Mexico, Across-Trench Earthquake

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