Estimation of Coda Wave Attenuation in Northern Morocco

Boulanouar, Abderrahim; Moudnib, Lahcen El; Padhy, Simanchal; Harnafi, M.; Villaseñor, Antonio; Muset, Josep Gallart; Pazos, Antonio; Rahmouni, Abdelaali; Boukalouch, Mohamed; Sebbani, Jamal

doi:10.1007/s00024-017-1726-4

Cited by 11 publications

(3 citation statements)

References 39 publications

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“…Each station exhibits relatively low values of quality factor (Q) and high n values. These values are comparable to the ones evaluated in other regions with high tectonic activity such as Aswan Reservoir area Egypt [Mohamed et al, 2010], Saurashtra Region Gujarat (India) [Sharma et al, 2012], Kumaun Himalaya [Singh et al, 2012], Baikal Rift System [Dobrynina et al, 2016], Northwestern Himalayan (India) Region [Kumar et al, 2016], Northern Morocco [Boulanouar et al, 2018]. Then our results suggest that the Armutlu Peninsula has high tectonic and seismic activity.…”

Section: Resultssupporting

confidence: 89%

Determination of Coda Wave Attenuation Characteristic of the Armutlu Peninsula and Its Surroundings (Middle Marmara Region, Turkey).

Yavuz

Barış²

2019

Annals of Geophysics

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The Armutlu Peninsula, is located in a geologically complex system on the North Anatolian Fault Zone and inside the high populated Marmara Region. Due to its location and importance, the Marmara Region has been subject to various studies in the past; now, this study is aimed to determine the local attenuation characteristic of the Armutlu Peninsula. In this study, 75 earthquake data that were recorded between 2013-2014, were analyzed by 9 seismic stations. The magnitudes (Ml) and the focal depths of the earthquakes vary from 1.5 to 3.3 and 0.9 to 16.9 km, respectively. A single back-scattering model was used for calculation of the coda wave quality factor. The lapse times were determined between 20 and 40 s at intervals of 5 s and they were filtered at central frequencies of 1.5, 3, 6, 9 and 12 Hz band-pass designed filter. Minimum 5 signal/noise ratio and 0.7 correlation coefficient data used to obtain reliable results. The CODAQ subroutine integrated in the SEISAN software was used for data processing. For each station, low values of the quality factor at 1 Hz (Q o ) and high values of the frequency dependent parameter (n) were determined. In the Armutlu Peninsula and its surroundings, Q c =51f 0.91 for 20 s and Q c =112f 0.72 for 40 s window lengths were calculated by using 9 stations. There is a tendency between increasing Q o and decreasing n parameters. Otherwise, for station TRML, located near the geothermal hotspot, these parameters are in direct proportion with each other, as Q c =46f 0.97 for 20 s and Q c =74f 1.06 for 40 s window lengths. These parameter changes are directly connected with the geothermal activity. the rate of coda wave attenuation [Aki, 1969]. Local/regional recorded coda waves (up to 100 km epicentral distance) and their power spectra as well as coda duration are relatively independent from the focal distance [Aki and Chouet, 1975]. Q c determination studies are generally performed in tectonically active fields, active volcanic regions, earthquake swarm areas, magmatic flows and geothermal areas [

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Section: Resultssupporting

confidence: 89%

Determination of Coda Wave Attenuation Characteristic of the Armutlu Peninsula and Its Surroundings (Middle Marmara Region, Turkey).

Yavuz

Barış²

2019

Annals of Geophysics

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“…Several studies have been conducted using the coda waves of local earthquakes to determine the rate of energy decay and the seismic attenuation. This energy decay rate is then used to estimate the total seismic wave attenuation in the Earth, represented by the parameter Q [Aki and Chouet, 1975;Gupta et al, 1996;Sato et al, 2012;Boulanouar et al, 2018;Arab et al, 2020]. Consequently, the lapse-time dependence of Q c is attributed to the combined effects of multiple scattering and depth.…”

Section: Crustal Attenuation Tomographic Image Of Northern Moroccomentioning

confidence: 99%

Crustal Attenuation Tomographic Image of Northern Morocco: Indication of High Tectonic Activities

Najim,

El Hilali,

Timoulali

et al. 2024

Annals of Geophysics

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Northern Morocco is known by its complex tectonic activity and has been the subject of various geophysical and geodynamic studies aimed to understand the physical properties and composition of the Earth’s crust and upper mantle. The waveforms of earthquakes recorded by the Topo – Iberia – Picasso seismic networks from 2008 to 2012 are analyzed to determine the decay properties of the coda wave and map the attenuation and absorption properties of the crust in this region. The coda quality factor Qc was estimated in five non‑overlapping frequency windows, ranging from 1.5 to 24 Hz, using recordings of local earthquakes. The measurements of Qc were then used to create maps of the absorption quality factor (Qi) using a linearized approximation. These maps were compared with the tectonic settings of the region to gain further insight into the crustal properties. Lateral and vertical variations of the coda quality factor (Qc) were investigated by creating a three‑dimensional tomographic image of the region. The results showed strong lateral variations of absorption in the northern part of Morocco, indicating high tectonic activity. Areas with high tectonic activity and high absorption were characterized by low values of Qc, while areas with low tectonic activity and low absorption had high values of Qc. The areas with thick cover sedimentary materials and shallow geothermal activity showed low‑frequency absorption. When compared to previous studies in northern Morocco, the study provides new information about the three‑dimensional attenuation model of the Earth’s crust.

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“…In recent years, the Rif area in northern Morocco has witnessed several events (Al Hoceima earthquakes of 1994,2004, and 2016) (Kariche et al, 2018;Boulanouar et al, 2013, Galindo-Zaldivar et al, 2018. Al Hoceima is one of the seismically active areas in northern Morocco (Boulanouar et al, 2018). Large seismic events that have been recorded and documented in seismic catalogs and research papers are evidence of this fact.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Seismic Kappa Parameter and Near-Surface Attenuation in Morocco

Boulanouar¹,

Rahmouni²,

Zian³

et al. 2022

Ecol. Eng. Environ. Technol.

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The goal of this study is to estimate the kappa (κ) parameter for a group of 12 broadband stations, located in different geological structures in Morocco, a country with moderate seismic activity. In this study, the kappa, κ has been obtained from the spectral analysis of the shear waves of 42 earthquakes, recorded in Morocco. Using 321 seismograms recorded in the period between 2009 and 2012 by the Picasso Project, the average κ-values have been computed from the horizontal components. For each station, the relationship between κ values and the hypocentral distance was determined. We separately investigated and studied the distance dependence of the stations located on soft soil and hard rock sites. The estimated average factor of the κ value ranges from 0.0682 for the hard sites to 0.0763 for the soft sites, with 0.072 as an average value. The lack of a significant correlation found between κ and magnitude at all stations considered in this study suggests that kappa is mainly dependent on local site characteristics. To the best of our knowledge, no studies related to kappa parameter estimation have been published for this region. The results generated in this study can be used for the seismic hazard evaluation of Morocco.

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Estimation of Coda Wave Attenuation in Northern Morocco

Cited by 11 publications

References 39 publications

Determination of Coda Wave Attenuation Characteristic of the Armutlu Peninsula and Its Surroundings (Middle Marmara Region, Turkey).

Determination of Coda Wave Attenuation Characteristic of the Armutlu Peninsula and Its Surroundings (Middle Marmara Region, Turkey).

Crustal Attenuation Tomographic Image of Northern Morocco: Indication of High Tectonic Activities

Estimation of Seismic Kappa Parameter and Near-Surface Attenuation in Morocco

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