It is widely believed that the moment tensor (MT) solution of an earthquake with a nondouble couple moment tensor gives significant information about the source mechanism. An interesting topic in non-DC source studies is the relationship among non-DC events, multiple DC events, and complexity in fault segmentations.This study presents a non-DC tectonic earthquake (forward modeling). This means that in the modeled moment tensor, there are no volumetric components. This model was made by adding the seismograms of the two 100% double couple event close lying, thus their seismograms overlap with each other. Then, an investigation is made of the seismic moment of the second subevent, frequency band used in the inversion and also the temporal and spacial separation between two subevents on the result of the inversion. This study focuses on the spacial complex source with Mw ~5. Based on empirical relations between moment magnitude and ruptured area (Somerville et al, 1999), the fault plane of an earthquake could not be larger than 11 km2, which could not be “seen” in our MT analysis (our MT inversion was run at frequency bands between 0.02-0.1 Hz). Thus, this inversion was not a pure DC MT inversion for two subevents at the same point but allowed their time separation to vary. The results show that the mechanism of the second subevent is dependent on the frequency band use and its accuracy is related to the higher frequencies used in the MT inversion (>0.09). It must be noted that the DC percentage of the moment tensor is dependent on the separation between subevents. The investigation shows that, by increasing the separation between two subevents, the DC percentage reaches higher values, perhaps because of fewer overlaps of the seismograms.We used the ISOLA package developed by Zahradnik et al, (2005) for the MT inversion, centroid location and time. This package is based on the Kikuchi and Kanamori, (1991) method for the teleseismic study of large earthquakes. ISOLA was developed for local and regional distances. For forward modeling of the complex source, we used the CPS package developed by R.B Herrmann in Saint Louis University.Finally, we attempt to model the real data. The 2005/05/01 Mw 5 Central Iran earthquake is investigated based on the results of the synthetic test conducted in the first part. A waveform inversion is performed at near-regional stations at frequencies 0.02– 0.07 Hz to search for the optimum 3D location and time of the centroid, using broadband station waveforms from the IIEES network. For calculating the Green function, two crustal velocity models were used, namely Ghods et al, (2010) and Walter, (2000). The Ghods et al, (2010) provides a higher correlation between observed and synthetic data.The optimum depth for centroid is 7 km. The stability of the MT inversion was investigated by the jackknifing method, and, finally, those stations which had low correlation between the observed and synthetic data were eliminated. The DC percentage of the moment tensor during the inversion was changed from 7 to 50%, which made this event a candidate for source complexity in order to study whether this earthquake could be interpreted as having two point sources lying close to each other. MT inversions were executed in frequency ranges from 0.02-0.07 to 0.02-0.13 Hz by adding 0.01 in each run.The second subevent had no significant impact on the waveform matches (about 2%). The mechanism of the first subevent was stable during the inversion and made the same correlation as the deviatoric MT inversion, but the mechanism of the second subevent changed considerably as a result of the changes in the frequency band of the inversion.The time separation between two subevents was about 6 to 8 seconds in different runs, which is unacceptable for earthquakes with magnitudes of approximately ~5, for which the fault area is approximately 11 km2. Thus, the two point sources model for this earthquake seems not to be a better model than the one point source. We also endeavored to model the Mw 5.7, 2006/03/25 Fin earthquake in southern Iran. The pure DC source model (for frequencies higher than 0.1 Hz) for this earthquake shows two subevents with a 10 km separation from each other.

Accurate focal depth estimates are essential for the correct interpretation of seismicity data in terms of regional tectonics and earthquake hazard assessment. Published global earthquake catalogues are a common source of focal depth information, but how accurate are they? We compare estimates of focal depths from the Harvard CMT catalogue and the Engdahl et al [8] relocations of the ISC catalogue with those determined by teleseismic waveform inversion methods, and find that the catalogues can be in error by up to 60km.

In this study, attenuation behavior of Moderate to large earthquake aftershock sequences occurred in Iranian plateau as been investigated according to the empirical Omori Law. Due to proper recordings of instrumental earthquakes from 1990 to 2012, important earthquakes of this period were selected. After determination of aftershock sequences using temporal-spatial window defined by Gardner & Knopoff (1974), 14 sequences having enough recordings and appropriately distributed over the Iranian plateau were investigated in terms of attenuation behavior curve. Therefore, the Omori curve and parameters (p, c and k) were plotted and calculated for each sequence. Results show that for the Iranian plateau earthquakes, p-values range between 0.39 and 2.7, parameter c values vary from 0.01 to 5, and paremeter k shows values in the range of 10 to 1427.4. This high variability is taken to indicate not only a variety of aftershock occurrence patterns in the Iranian plateau, but also an incomplete and inhomogeneous earthquake catalog. By using the present database, therefore, it is not easily possible to have a zonation based on temporal attenuation behavior of aftershock activities over the Iranian plateau. However, the estimations of aftershock attenuation rate for each locality can be used to analyze seismic hazard. Present study showed that the p-values and hence the aftershock attenuation rates in the Alborz and Zagros regions are greater than those in the eastern and central parts of Iran. The higher the rate, the greaterthe energy release, which means a shorter time to gain background seismicity. This result is comparable and consistent with the amount of energy released in theseismotectonic zones of the Iranian Plateau. Moreover, 7 out of 14 earthquake sequences have secondary aftershocks, which give two values for each Omori parameters. Results demonstrated that with a higher earthquake magnitude, the occurrence of the next big event as well as secondary aftershocks is more likely. Furthermore, for the 7 sequences with secondary aftershocks, a trend of P2 variations is observable. P2 is more than 2.5 for 3 of these sequences that have magnitudes above 7 and occurred along the Iranian plate boundaries. For the other 4 intraplate events, which have magnitudes less than 7, P2 is less than 2. This might be due to a magnitude change or tectonic setting and distance of hypocenter to the main fault nodes. Resultsalso showed that the c and k parameters are highly affected by number of recordings in the catalog. A more complete and homogeneouscatalog would produce well-constrained values for these parameters, which in turnmakes the analysis of the seismicity and physics of the fault zone more accurate.

In this paper, a new kind of ring damper composed of three rings is introduced and investigated numerically and experimentally. The proposed damper combined three steel ring damper in order to dissipate energy of two different level of predefined excitation such as Moderate and severe one. first fuse (outer pipe) and second fuse (inner pipes) can absorb energy in Moderate and severe earthquakes respectively. To evaluate the introduced damper, numerical finite element models are developed to clarify the effect of thickness and diameter variation of main fuse. Results of force-displacement curves obtained from cyclic loading confirmed the two level performance of models. Stiffness and fore increase improved the energy dissipation capacity after the predefined displacement gap. Also, damping ratio are calculated for all samples and results showed that equivalent damping ratio have been improved when main fuse was engaged. Two experimental samples have been constructed based on numerical models and examined under cyclic loading. Defined results of experiments showed that samples could tolerate 20 cycles of 10 times of yield displacement amplitude. Good agreement between numerical model and experimental samples results have been achieved.

During one year, the Bardsir earthquake (2010/07/31, MS=5. 8), the Kahnooj earthquake (2011/06/15, MS=5. 7) and the Sirch earthquake (2011/06/26, MS=5. 2) have occurred in Kerman province (one of seismologically active area in eastern Iran). The earthquakes have been relocated and processed using local and regional recorded seismograms. Mechanism of the earthquakes were calculated using the first P motion method. Processing both locations and focal mechanisms indicate that these earthquakes are probably related to the Lalehzar, Sabzevaran and Golbaf fault systems, respectively. Bardsir and Sirch earthquake faults dip northeastward and Kahnooj earthquake fault dips eastward, indicating that both source faults dip steeply. Mechanisms of the earthquakes were right lateral strike slip, reverse with right lateral strike slip component and reverse mechanism, respectively. Finally, this research is in accordance to the field investigations, in which the maximum intensity in MM and JMA scales was estimated ~VI near epicentral area and no co-seismic surface rupture were detected for these earthquakes.

Buildings and other structures experience more damages in near-field earthquakes due to existence of high period pulse in the records of near-field earthquakes. These pulses may not be existed in all near-field records. Therefore, to evaluate the effect of near-field earthquakes on structures realistically, a probabilistic approach is used to evaluate the probability of different damage state in near- and far-field earthquakes. In this method, the damage of structure is evaluated by estimation of fragility function of structure through numerous non-linear dynamic analysis subjected to different ground motion records. To compare the effect of near-field and far-field earthquakes on low-rise Moderate reinforced concrete moment, a two and three story concrete frame were selected and designed according to Iranian code. The fragility function of frames was estimated in near- and far-field earthquakes. In near-field earthquakes, mixture of pulse like and non-pulse like records were considered. The results have shown that no meaningful difference between probabilities of failure of near- and far-field was observed. Therefore, it can be concluded that although the near-field earthquake may cause severe damages on structures due to existing impulses in some records, from the probabilistic point of view and considering all near-field records, this effect is not significant.

In view of Iran,s being located on one of the tow seismic belts of the world as well as the very existence of copious geologic fault, the occurrence of earthquake in the plateau of Iran is but a natural phenomenon. Iran is one of the ten cataclysm–generating countries and the sixth in number of the world earthquake - generating countries. That is why earthquake inflicts high death toll of human lives. Moreover the seismic zone encompasses 90% of the territorial area of our country . But what is more important in this regard, is the regrettable location of cities and metropolises (such as Tehran, Tabriz…) that have been built on or within the vicinity of geologic fault and, as a result, are unquestionably prone to earthquake menace.This is because Iran is one of the countries that have taken on their formation through innumerable geologic faults whose movements cause the release of stored energy leading to reccurrence of earthquake meting out heavy human casualty and immense property losses in urban areas. In this paper, endevours will be made to probe into the cause of earthquake generation in the plateau of Iran and the negative effects of activities of faults on some of the cities taken as models and recall the dangers entailed therein.

earthquakes have long been associated with change and destruction. Human has always been looking for a solution to identify and predict the occurrence of earthquakes. In order to identify the occurrence of an earthquake, other events that can be a sign of the conditions of the earthquake should be examined. In order to study these conditions, the status of climatic variables in hourly, weekly and monthly time periods was studied. Even theories about the relationship between weather and earthquakes have long been proposed by the ancient Greek philosopher (Aristotle) called "earthquake weather". He proposed the theory that the weather would be warm and calm before the earthquake, and the next theory he stated was that earthquakes occur in calm and cloudy conditions. The U.S. military has since examined the relationship between the weather and its relationship to earthquakes.Identifying the relationship between weather and earthquakes can help to predict and reduce financial and life losses, so in this research, the weather conditions at the time of the earthquake in some of the major earthquakes of Iran have been investigated.  In this article, using the hourly, weekly and monthly data, the observed meteorological variables at the time of the earthquake were investigated. These variables include: Temperature (in degrees Fahrenheit), Dew point (in degrees Fahrenheit), Relative Humidity (in percent), Wind direction and wind speed (in meters per hour), Gusty wind (in meters per hour), Pressure (in inches), Precipitation (in inches), Cloud Cover, Solar Altitude, Lunar Altitude, General Weather Conditions on an hourly, daily, weekly and monthly basis can be named boards that were examined. The studied variables from the time before the earthquake to after the specified time intervals were examined. Due to the large number of these charts, data and maps, only some of them were presented as examples in this article. Based on the study, these two theories are rejected due to the impossibility of generalization to all earthquakes, and it is suggested that it is due to the occurrence of a series of simultaneous changes in the Earth's system, including the biosphere, lithosphere, hydrosphere and atmosphere.Based on the observed data, changes can be seen in most of the weather factors at the time of the earthquake. Air temperature, dew point, lunar altitude, solar altitude, relative humidity increased and then decreased, pressure decreased and then increased. The direction of the wind changed at the moment of the earthquake and as it can be seen, the direction of the wind was not observed at the time of the earthquake in any of the hours of that day. The wind speed has decreased at the moment of the earthquake. These changes in a system that includes cryosphere, biosphere and atmosphere.It happens in a moment and this change can be clearly seen in most weather factors. It is suggested that these changes be known as the "Earth Systemic Evolution Theory".These changes can be known as the "Earth System Evolution Theory". This theory is presented for the first time in this article.

Context: The aim of the study was to review medical aspects of earthquakes in Iran in order to help clinicians obtain a better understanding of this natural disaster and select better therapeutic methods. Methods: Two authors independently searched articles through scientific databases, such as PubMed, MEDLINE, Wiley, EMBASE, ISI Web of Knowledge, andScopus. The keywords that were applied to search these articles included: Earthquake, disaster, Iran, physical phenomena, geological phenomena, health, trauma, medicine, wounds, and injuries. Tworesearchers independently assessed titles and abstracts of all studies and then included them based on the relevance. Results: Fourteen studies were included in the current study. Fractures were the most common injury. The results showed hospitals, relief agencies, and municipal services should be built in a manner appropriate for earthquake conditions. A gender-sensitive approach for planning and management of trauma patients after a disaster could allow better and more effective healthcare delivery. Conclusions: This review of earthquakes that occurred in Iran aimed to provide a better understanding of this natural disaster, and allow selection of better therapeutic methods, which is important in disaster management.