Estimation of Site Effects in the Iranian Plateau Using the Quarter-Wavelength Method

The characteristics of strong ground motion at a given site depend upon the source mechanism, the transmission path together with the geological characteristics of source to the site, and the local soil conditions at the site, mostly known in the engineering and seismological literature as site effects. In the context of the stochastic simulation methods (e.g. Boore 1983), site effects play a significant rule in ground-motion studies. The objective of this paper is the assessment of site effects (both crustal amplification and near surface attenuation) in the Iran plateau. The effects in different parts of Iran were estimated based on the average shear wave velocity of upper 30 m that is presented in site classification system of NEHPR. For deeper depths the global data of CRUST 2.0 model were used and shear wave velocity profiles in different depths were assessed accordingly. Afterwards, using the quarter-wave length method the crustal amplification have been determined for a grid of 1° by 1° over the whole country. In addition the near surface attenuation effect was estimated using the empirical correlation between kappa and shear wave parameters proposed by chandler et al. (2006). The final results are presented as site effects contours in the frequency range of most interest to engineers for the Iranian plateau

Improvements to seismicity forecasting based on a Bayesian spatio-temporal ETAS model

The epidemic-type aftershock sequence (ETAS) model provides an effective tool for predicting the spatio-temporal evolution of aftershock clustering in short-term. Based on this model, a fully probabilistic procedure was previously proposed by the first two authors for providing spatio-temporal predictions of aftershock occurrence in a prescribed forecasting time interval. This procedure exploited the versatility of the Bayesian inference to adaptively update the forecasts based on the incoming information provided by the ongoing seismic sequence. In this work, this Bayesian procedure is improved: (1) the likelihood function for the sequence has been modified to properly consider the piecewise stationary integration of the seismicity rate; (2) the spatial integral of seismicity rate over the whole aftershock zone is calculated analytically; (3) background seismicity is explicitly considered within the forecasting procedure; (4) an adaptive Markov Chain Monte Carlo simulation procedure is adopted; (5) leveraging the stochastic sequences generated by the procedure in the forecasting interval, the N-test and the S-test are adopted to verify the forecasts. This framework is demonstrated and verified through retrospective early forecasting of seismicity associated with the 2017-2019 Kermanshah seismic sequence activities in western Iran in two distinct phases following the main events with Mw7.3 and Mw6.3, respectively

Short Term Results of Arthroscopic Repair of Subscapularis Tendon Tear

Background:Despite being the largest rotator cuff tendon of the shoulder,the function and clinical relevance of subscapularis pathology has been largely ignored in the literature.Although many studies have focused on subscapularis tears recently,majority of them reported techniques for open repair. The advent of arthroscopy and   arthroscopic repair techniques has opened new frontiers in the diagnosis and repair of torn rotator cuff tendons, including the subscapularis.In this article,we review shortterm results of arthroscopic subscapularis repair. Method: Ten patients with subscapularis tendon tear of the rotator cuff were studied   prospectively including 8 men and 2 women with an average age of 49.7±12.8 years and an average delay in treatment of 23.3 months. Clinical outcomes, including the UCLAscore were assessed in all patients after 3 months of the surgery. Results: 6 patients were followed regularly for more than 6 months,while other 4 patients had a follow-up period of more than a year. The pain score improved from 1.75 to 9 and the UCLA score from 8.8 to 30.6.Conclusions: rthroscopic repair of subscapularis tendon tear results in significant subjective and objective improvement and high levels of patient satisfaction.

Investigation of Source Parameters of Roudbar-Manjil Earthquake Using Hybrid Simulation Method

For time history analysis of structures, appropriate records are needed. Due to the lack of strong-motion records from large earthquakes in some parts of Iran (e.g. Tehran region), earthquake simulation is a useful tool for studying strong-motion characteristics. In this study, a hybrid method has been used for obtaining source parameters of the 1990 Rudbar-Manjil earthquake (Mw7.3). In this simulation we assume fault plane, slip distribution and etc., then each parameter optimized after comparing simulated results with observed ones. In this hybrid method low frequency component of record obtained by the wave-number scheme that is a deterministic method and high frequency component obtained by the stochastic simulation method of Boore (2003), extended to the case of finite faults. Records from the stochastic method filtered with a high pass filter (fc=1.5 Hz) and results from the deterministic method filtered with low pass filter (fc=1.5 Hz), then the time-histories have been combined/added in the time domain. Final results have been compared with observed PSA and PSV in specified strong-motion stations. After comparing, optimized parameters have found, then based on this optimized parameters intensity contour has drawn; simulated intensity contours show good match with and observed ones. Best parameters are 2500 m/s for rupture velocity and 3 seconds for ramp function (i.e. rise time) and 36.82° N and 49.40° for earthquake epicenter. The results are important for the assessment of hazards in other seismically active parts of Alborz mountains (e.g. Greater Tehran area)

Time-Dependent Probabilistic Seismic Hazard Analysis Using the Simulated Records, the Case of Tehran

Common attenuation equations are developed by seismic records which belong to earthquakes that have happened so far. Although there are many recorded data during last 50 years, it is not possible to consider all possible wave propagation paths, site types and fault rupture mechanisms inclassical attenuation relations. This fact becomes more serious in near field cases and a common shortcoming in most attenuation equations is their low accuracyin estimation of near field parameters.Many important cities of the world such as Tehran are located nearby some active faults. For example, the North Tehran Fault is such a closeseismic source to Tehran Metropolitanarea andcould be considered asa near field source. Therefore, it is necessary to evaluate near field effects in most of hazard analyses, risk management programs, structural designs, etc.In past, it was routine to use attenuation equations in hazard analyses. In this project for avoiding from insufficient performance of attenuation equations in near field, proposed simulation datum byZafarani, et al., (2012), were used directly in the hazard analysis without converting them into attenuation equations.Besides, time dependent hazard analysis (Non-PoissonianModel) was used to taking into account the probable seismic activity of the North Tehran Fault

Arthroscopic Repair of Complete Tear of Rotator Cuff

Background:Rotator cuff tear is one of the most common causes of shoulder complaints in the elderly.Based on the severity and patient's condition,a variety of  methods applies to manage the tear and surgery is an important method,which could  be done by open or arthroscopic technique. The current study aimed to investigate  and report short-term results of arthroscopic repair of complete rotator cuff tears.Methods: This was a cross-sectional study on 183 patients who underwent arthroscopic surgery to repair rotator cuff tear in three different hospitals of Tehran between January 2003 and August 2006. Of all patients, 107 cases included in our  study,which had a complete rotator cuff tear,and at least one-year follow up record.   89 patients (56 male and 33 female)attended assessment sessions and were evaluated by UCLA(University of California,Los Angeles) Shoulder and Elbow Scoring System,pre- and post-operatively,and acromioplasty was performed in 83 patients.Results:With a mean age of 53.2 ± 15.8 (32-71) years,the average UCLA score was 11.3 before the surgery and 31.4 post-operatively.There were 11 patients with excellent scores,62 good,11 fair,and 5 poor scores.9 out of 11 cases with excellent score and 34 out of 62 with good score were younger than 55 years;however,13 cases were older than 60 years amongst 16 fair or poor scores.Conclusions:Arthroscopic repair of complete rotator cuff tear would cause a significant improvement in a short-term period and results are better in younger patients,through the UCLA scoring system.