N. Mousavi; J. Ebbing; V. Ebrahimzadeh Ardestani
Abstract
We apply two forward methodologies in order to study density and susceptibility structure of the crust and upper mantle. The study area is a profile crossing the Zagros collision zone located as margin of Eurasia-Arabia converging plates. Gravity modeling focusing on lithospheric structure is performed ...
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We apply two forward methodologies in order to study density and susceptibility structure of the crust and upper mantle. The study area is a profile crossing the Zagros collision zone located as margin of Eurasia-Arabia converging plates. Gravity modeling focusing on lithospheric structure is performed in thermodynamic framework in which chemical composition is important and provides an understanding of deep layers in lithosphere like Moho and Lithosphere-Asthenosphere Boundary. Results on the crustal thickness show minimum values beneath the Arabia Platform and Central Iran (42–43 km), and maximum values beneath the Sanandaj Sirjan zone (SSZ; 55–63 km). Results on the lithosphere thickness a long profile also indicate that the Arabian lithosphere is approximately 220 km thick, toward North West of Iran especially below the Central Iran rises up to 90 km. In the profile (central Zagros), lithosphere thinning occurs in wider region, from the Zagros fold thrust belt to the Sanandaj Sirjan zone. Our results are based on application of average Proterozoic mantle compositions in modeling beneath the Arabian Platform, Mesopotamian Foreland Basin and Iranian Plateau. After rough estimation of upper crust via integrated modeling by elevation, gravity and geoid data, the distribution of density and magnetic susceptibility values allows us to perform a study in crustal scale. Afterwards, determination of the homogenous blocks with the same density and susceptibility, the geometry to different crustal layers including sediments, upper, middle and lower crust deep to Moho boundary were refined in crust-scale study based on regional model in lithospheric scale. Presence of Main Zagros Fault is a bold point in our modeling which leads to better fit of gravity data.
Sh Eghtesadi; M Shokati Amghani
Abstract
Modelingof bouguer gravity anomaly and tsunami warning due to Makran subduction zone (case study: Beris region)
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Modelingof bouguer gravity anomaly and tsunami warning due to Makran subduction zone (case study: Beris region)
A. H. Rajaee; M. Mokhtari; K. Priestley; D. Hatsfeld
Abstract
Using teleseismic body waves, this paper presents the crustal and lithospheric structure in the central part of the AlborzMountains for the first time. The region has been known as a very active and seismogenic locations in the past, characterized by strong earthquakes and complex structures. Tehran, ...
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Using teleseismic body waves, this paper presents the crustal and lithospheric structure in the central part of the AlborzMountains for the first time. The region has been known as a very active and seismogenic locations in the past, characterized by strong earthquakes and complex structures. Tehran, the capital of Iran, is located on the southern part of the region. The aim of this study is to determine Moho depth and its variation beneath the Central Alborz with high resolution and accuracy. The crustal structure of the Central Alborz beneath 26 broadband stations from a temporary dense seismological network was determined by using recorded data deployed for a period of 4-6 months. We first summarize an analysis of the teleseismic P-wave receiver function beneath each station. Next, we use joint inversion of receiver functions with surface wave dispersion data calculated for the center of network. Results of this research are shown as cross-sections through N-S azimuth of the profiles which passes across the AlborzMountains. Our study shows a thickening in the central part of the AlborzMountains crust down to 55 km relative to 48-50 km crustal thickness beneath northern part of the Central Iran. The crustal thickness is close to 44 km beneath the southern coast of the South Caspian Sea Block. These results are completely unlike with most of the other previous suggested crustal thickness. Based on our results, the AlborzMountains with a high average elevation can be considered with a crustal root.
