Temporal characteristics of seismicity in the Alborz and Zagros regions of Iran, using a multifractal approach

Ahmad, Zaini; Agh-Atabai, Maryam

doi:10.1016/j.jog.2009.01.003

Cited by 29 publications

(8 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Especially for the year 2004 (initial establishment of the network), data availability from this network is sparse. In addition, strain in the Alborz mountains is released by rare strong earthquakes (Zamani and Agh-Atabai, 2009). Therefore, only a few events per year are strong enough to be processed with standard methods and from broadband data alone.…”

Section: Discussionmentioning

confidence: 99%

Combined Inversion of Broadband and Short-Period Waveform Data for Regional Moment Tensors: A Case Study in the Alborz Mountains, Iran

Donner

Rössler

Ghods

2014

Bulletin of the Seismological Society of America

View full text Add to dashboard Cite

In this study, we suggest a novel approach for the retrieval of regional moment tensors for earthquakes with small to moderate magnitudes. The first modification is the combined inversion of broadband and short-period waveform data. The broadband waveforms are inverted in a frequency range suitable for surface waves, whereas for the short-period data a frequency range suitable for body waves is applied. The second modification is the use of first-motion body-wave polarities to select the most probable solution out of all solutions from inversion. To combine three different criteria for selecting the most probable solution (i.e., residual from inversion, doublecouple content of solution, number of nonmatching first-motion body-wave polarities), the L2 norm is applied to the normalized parameters. We chose five earthquakes within the Alborz mountains, Iran, as a case study (3:1 ≤ M w ≤ 4:1). In this area, several factors exacerbate the difficulty of performing inversion for moment tensors, for example, a heterogeneous station network and large azimuthal gaps. We have demonstrated that our approach supplies reliable moment tensors when inversion from broadband data alone fails. In one case, we successfully retrieved a stable solution from short-period waveform data alone. Thus, our approach enables successful determination of seismic moment tensors wherever a sparse network of broadband stations has thus far prevented it.

show abstract

Section: Discussionmentioning

confidence: 99%

Combined Inversion of Broadband and Short-Period Waveform Data for Regional Moment Tensors: A Case Study in the Alborz Mountains, Iran

Donner

Rössler

Ghods

2014

Bulletin of the Seismological Society of America

View full text Add to dashboard Cite

show abstract

“…The Mountain Front Fault, which is a segmented reverse fault zone, coincides with the 1,500 m contour and the major zone of earthquake activity to the southwest of the Simply Folded Belt. The Zagros Frontal Fault, also known as the Zagros Foredeep Fault, represents the frontal edge of the Zagros Fold-Thrust Belt and separates the alluvial basin of the Zagros to the southwest from the folded belt to the northeast (Zamani & Agh-Atabai, 2009). Plate convergence rate seems to control the forces driving seismic and aseismic deformation within mountain belts.…”

Section: Geological Settingmentioning

confidence: 99%

Assessment of relative tectonic activity in the Lar region, Zagros Fold‐Thrust Belt, SW Iran: Insights from geomorphometric analysis

Zarei,

Faghih,

Soleimani

et al. 2023

Earth Surf Processes Landf

View full text Add to dashboard Cite

The Zagros Fold‐Thrust Belt is a tectonically active region within the Alpine‐Himalayan orogenic system resulting from ongoing convergence between Afro‐Arabian and Central Iranian plates. The presence of various geomorphic features in this region provides an ideal natural case for identifying deformed landforms resulting from active tectonics. The relative tectonic activity along the Lar and Didehban faults within the Zagros Fold‐Thrust Belt, SW Iran was evaluated using six DEM‐derived geomorphic indices: the stream‐gradient index (SL), drainage basin asymmetry (AF), hypsometric integral (HI), valley floor width‐valley height ratio (Vf), drainage basin shape (Bs), and mountain‐front sinuosity (Smf). These indices were combined to yield the relative active tectonics index (Iat) that allows the variation of tectonic activity along the Lar and Didehban faults to be related to variations in rates of incision, tectonic tilting and uplift. This variable tectonic activity was characterized by different Iat values along the faults. The low to high relative tectonic activity (class 1: 1 < Iat < 1.5, class 2: 1.5 < Iat < 2, class 3: 2 < Iat < 2.5, class 4: 2.5 < Iat) correlates with variable geomorphic features along the faults. The results of this study present an approach for assessing the effects of active tectonics and also for sustainable land use planning over a large area.

show abstract

“…11. Упрощенная сейсмотектоническая карта Ирана [Zamani, AghAtabai, 2009]. Обозначения: DRF -разлом Doruneh, KBF -разлом KuheBanan, KQL -линия разлома KazerunQatar, MFF -разлом Mountain Front, MRF -разлом Main Recent, NBF -разлом Nayband, OL -линия разлома Oman, ZFF -разлом Zagros Frontal.…”

Section: краткое описание сейсмических поясов и зон землиunclassified

Seismic Belts and Zones of the Earth: Formalization of Notions, Positions in the Lithosphere, and Structural Control

Шерман¹,

Злогодухова²

2011

Geodyn. Tectonophys.

View full text Add to dashboard Cite

This publication is aimed at formalization of the notions of «seismic zone» and «seismic belt». A seismic zone (SZ) is a territory defined and contoured in a technically active area. Within the limits of this territory, more than 10 seismic event with М>3 (К>9) occurred in the specified period of time (typically, 50 years), or the number of seismic event is not below a certain statistically relevant value. The external contour of SZ should be drawn according to the isolines of the corresponding density of registered earthquakes with М≥3, pending no less than three events within the given square area. In each case, selection of contours of SZ should be determined so that it can provide for classification of SZs. SZ should correspond to one or several tectonic structures. The interior structure of SZ can be zoned according to densities of earthquake epicentres.A seismic belt (SB) is a structure with a uniform geodynamic regime, wherein seismic zones are closely spaced. Typi cally, such structures are margins of plates or large intraplate blocks. In real time, SB is generally characterized by a perma nent state of lithospheric stresses. Stress vectors in local segments of SB may differ from the dominant type of stresses. They can be variable due to changes in strike of local and regional faults which control seismicity and also due to various direc tions of zones of the recent lithospheric destruction.The Earth's SBs and SZs are mapped. SBs and a number of most important SZs are briefly described. Main parameters of SBs and SZs are tabulated. Based on the available data on SBs and SZs and taking into account the common geodynamical settings and elongated localities of earthquake foci, we suggest that it is required to evaluate structural factors controlling the seismic process and its components (locations of earthquake foci) at all the hierarchic levels, i.e. seismic belts, seismic zones, fault zones wherein stresses are concentrated, and structures wherein earthquake foci are located.Due to differences in the structural factors of control and scaling of SB and SZ manifestation, criteria for occurrence of earthquakes of various magnitudes are significantly different. Rare catastrophic earthquakes in SB result from the evolution of interplate and large interblock margins in the geochronological scale intervals and/or disturbances of the evolution regu larities due to catastrophic seismic event in the adjacent SB. Developing tectonophysical models of SBs is a future challenge.In SZ, earthquakes of medium magnitudes and rare strong seismic events results from the impact of strain waves on the megastable state of the recent lithospheric destruction zones which comprise the SZ structure. Time spans between seismic events in SZ are estimated in real time scales (decades, years, months) and thus can be considered instant in relation to peri ods of the geological evolution of interplate margins and other large structural margins (hundred thousand years, million years). In terms of the given time evaluation, the ...

show abstract

Temporal characteristics of seismicity in the Alborz and Zagros regions of Iran, using a multifractal approach

Cited by 29 publications

References 47 publications

Combined Inversion of Broadband and Short-Period Waveform Data for Regional Moment Tensors: A Case Study in the Alborz Mountains, Iran

Combined Inversion of Broadband and Short-Period Waveform Data for Regional Moment Tensors: A Case Study in the Alborz Mountains, Iran

Assessment of relative tectonic activity in the Lar region, Zagros Fold‐Thrust Belt, SW Iran: Insights from geomorphometric analysis

Seismic Belts and Zones of the Earth: Formalization of Notions, Positions in the Lithosphere, and Structural Control

Contact Info

Product

Resources

About