Cumulative Moment Research Articles

McLeish Distribution: Performance of Digital Communications Over Additive White McLeish Noise (AWMN) Channels

The objective of this article is to propose and statistically validate a more general additive non-Gaussian noise distribution, which we term McLeish distribution, whose random nature can model different impulsive noise environments commonly encountered in practice and provides a robust alternative to Gaussian noise distribution. In particular, for the first time in the literature, we establish the laws of McLeish distribution and therefrom derive the laws of the sum of McLeish distributions by obtaining closed-form expressions for their probability density function (PDF), cumulative distribution function (CDF), complementary CDF (C2DF), moment-generating function (MGF) and higher-order moments. Further, for certain problems related to the envelope of complex random signals, we extend McLeish distribution to complex McLeish distribution and thereby propose circularly/elliptically symmetric (CS/ES) complex McLeish distributions with closed-form PDF, CDF, MGF and higher-order moments. For generalization of one-dimensional distribution to multi-dimensional distribution, we develop and propose both multivariate McLeish distribution and multivariate complex CS/ES (CCS/CES) McLeish distribution with analytically tractable and closed-form PDF, CDF, C2DF and MGF. In addition to the proposed McLeish distribution framework and for its practical illustration, we theoretically investigate and prove the existence of McLeish distribution as additive noise in communication systems. Accordingly, we introduce additive white McLeish noise (AWMN) channels. For coherent/non-coherent signaling over AWMN channels, we propose novel expressions for maximum a priori (MAP) and maximum likelihood (ML) symbol decisions and thereby obtain closed-form expressions for both bit error rate (BER) of binary modulation schemes and symbol error rate (SER) of various M-ary modulation schemes. Further, we verify the validity and accuracy of our novel BER/SER expressions with some selected numerical examples and some computer-based simulations.

Detailed spatiotemporal analysis of the tectonic stress regime near the central Alpine Fault, New Zealand

We construct a new data set of 845 focal mechanisms derived from microseismicity recorded between late 2008 and early 2017, to investigate the state of stress near the central Alpine Fault, a major obliquely convergent plate boundary fault. We obtain an average maximum horizontal compressive stress orientation, SHmax, of 121±11°, which is uniform to first-order along the length of the central Southern Alps. We also make use of the local magnitudes of the earthquakes with focal mechanisms to examine the spatial patterns of seismic moment release and obtain a relatively uniform cumulative seismic moment release distribution adjacent to the central Alpine Fault, which appears to be independent of both the perpendicular and parallel distances to the fault. We observe an average angle between SHmax and the Alpine Fault of 66°, which is consistent with previous observations in the northern and southern sections of the Alpine Fault. This result implies that central Alpine Fault is not optimally oriented for reactivation. Detailed temporal investigations using two different approaches did not show any systematic change of the stress parameters with time. We also examine the distribution of the shear to normal stress ratio on the fault and do not observe any significant spatial variation along the Alpine Fault. This lack of variation combined with the high angle between the fault strike and SHmax implies that the fault is unfavourably oriented for slip.

Towards Improved Probabilistic Seismic Hazard Assessment for Bangladesh

This study aims to build on the existing knowledge and improve the overall PSHA results by modifying source, path and site characteristics for Bangladesh. Firstly, six potential seismotectonic zones have been re-defined based on the recent study of Wang et al. (J Geophys Res Solid Earth 119:3576–3822, 2014) and Nath and Thingbaijam (J Seismol 15(2):295–315, 2011), and the updated earthquake catalogue has been declustered using two methods. Important source parameters, such as recurrence b-values and maximum magnitudes, have been determined using the Maximum Likelihood and cumulative moment methods, respectively, and their uncertainties have been addressed using a logic-tree approach. Secondly, based on literature review and studies in neighboring countries, suitable GMPEs have been selected for the seismic zones and the uncertainties have been addressed using a logic tree approach. A significant novelty of the study lies in the consideration of the site effects by integrating Vs30 values throughout the country. The ground motions—PGA and SA (at 0.2, 1.0 and 2.0 s) are computed using GEM’s OpenQuake and presented in form of hazard maps for 2% and 10% probabilities of exceedance in 50 years as well as mean hazard curves and uniform hazard spectra. Disaggregation for capital city Dhaka has also been carried out to show the hazard contributions of magnitude–distance pairs. The spatial distribution of PGA and SA are found remarkably higher than previous findings, likely due to differences in parameters and uncertainties. The results show a marked increase (by almost 20%) in the observed ground motions with respect to those carried out previously by uniformly characterizing the whole country as a firm rock.

The effect of axial twist angle on in vitro cumulative injury load tolerance: a magnitude-weighting approach for axial twist exposures

Axial twisting exposures have been repeatedly identified as a risk factor for occupational low back pain and injury, but there is a need for an improved understanding of the role of axial twist magnitude and associated joint moment as modifiers of the cumulative load tolerance of intervertebral joints. The purpose of this study was to mathematically characterise the relationship between axial twist motion magnitudes and the cumulative load tolerance of porcine cervical functional spinal units. Twenty-four porcine functional spinal units were fixed in a mechanical testing system under compressive load (15% of compressive tolerance) and in a neutral flexion-extension posture. Specimens were axially twisted to 5, 7.5, 10, 12.5, 15 or 17.5 degrees at 1 Hz until failure or 21,600 total cycles. Cumulative applied axial twist moment was recorded, and exponential functions were fit to the twist magnitude-cumulative twist moment measures. Weighting-factor functions for cumulative axial twist moment injury risk were developed based on absolute axial twist magnitude and twist normalised to maximum range of motion. While caution should be used in extrapolating these findings to human evaluation, a developed non-linear weighting-factor model has potential for use in assessment of cumulative axial twist injury risk in occupational tasks.

Decrease in walking speed increases hip moment impulse in the frontal plane during the stance phase.

BackgroundIncreased daily cumulative hip moment in the frontal plane (i.e., the product of hip moment impulse in the frontal plane during the stance phase and mean steps per day) is a risk factor for progression of hip osteoarthritis. Although hip osteoarthritis generally causes a decrease in the walking speed, its effect on hip moment impulse in the frontal plane is unclear. The purpose of this study was to examine the relationship between decrease in walking speed and hip moment impulse in the frontal plane.MethodsWe used a public dataset of treadmill walking in 17 older adults (mean (SD) age: 63.2 (8.0) years). The subjects walked on the treadmill for 30 s under five conditions: (1) 40% of comfortable non-dimensional speed (CNDS), (2) 55% CNDS, (3) 70% CNDS, (4) 85% CNDS, and (5) 100% CNDS. The hip moment impulse in the frontal plane non-normalized (or normalized) to step length (Nm s/kg [or Nm s/(kg m)]) for each condition was calculated. Furthermore, the relationship between walking speed and hip moment impulse in the frontal plane non-normalized (or normalized) to step length was examined using regression analysis based on a previous study.ResultsA decrease in non-dimensional speed (i.e., walking speed) significantly increased the non-normalized (or normalized) hip moment impulse in the frontal plane during the stance phase. The relationship between walking speed and non-normalized (or normalized) hip moment impulse in the frontal plane was fitted by a second-order polynomial.DiscussionThis study revealed that a decrease in walking speed increased the non-normalized (or normalized) hip moment impulse in the frontal plane in healthy older adults. This finding is useful for understanding the relationship between walking speed and hip moment impulse in the frontal plane and suggests that a decrease in walking speed may actually increase the daily cumulative hip moment in the frontal plane of patients with hip osteoarthritis.

Back Analysis of Short-Term Seismic Hazard Indicators of Larger Seismic Events in Deep Underground Mines (LKAB, Kiirunavaara Mine, Sweden)

Back analysis for evaluation of the merits of the short-term seismic hazard indicators (precursors) used in the mines and their potential application for early warning was carried out for fourteen seismic events that potentially caused damage in Kiirunavaara Mine, Sweden, selected according to our designed criteria. Five short-term hazard indicators: Seismic Activity Rate (SAR), Cumulative Seismic Moment (CSM), Energy Index (EI), Cumulative Apparent Volume (CAV) and Seismic Apparent Stress Frequency (ASF) were tested. The behaviour of the indicators was studied using the parameters of all seismic events within a sphere around the hypocenter location of the analyzed seismic source within one month before the main (damaging) event. The size of the sphere equals the estimated radius of the analyzed seismic source (area of inelastic deformation). mXrap software (Australian Centre for Geomechanics) was used for data visualization, manipulation, analysis and extraction. The results from the main analysis showed a good agreement between the expected and actual behaviour of the SAR, CSM and CAV indicators. In overall, CSM and CAV ranked the highest positive/expected behaviour followed by SAR (Table 3). The EI and ASF ranked lowest and showed to be sensitive to the number of events within the source sphere. The rate of false warnings and missed warnings was also investigated for the 25 days-long period before the damaging events. A similar trend was observed as for the main analysed event. The results from this study can be used for further improvement of the short-term hazard estimations and early warning system in deep underground mines.

Experimental validation of a novel spine model demonstrates the large contribution of passive muscle to the flexion relaxation phenomenon

When an individual enters a maximally flexed spine position, their largest extensor muscles become electrically inactive despite a substantial extensor moment demand being placed on the low back; this is termed flexion relaxation. Stresses within intervertebral discs, ligaments, and passive muscles are thought to support this moment thereby allowing the extensor muscles to ‘turn off’. While the mechanical behaviour of the intervertebral disc and ligaments have been studied extensively, less is known regarding the moment supported by passive muscle tissue during spine flexion. Here we estimated the L4/L5 moment supported by the passive musculature during spine flexion based on experimentally derived architectural and material properties. We then tested the validity of the passive muscle prediction by determining whether the cumulative passive tissue moment (including passive muscle, intervertebral discs, and ligaments) would support the extensor moment demand—calculated with inverse dynamics—near maximum spine flexion. The model predicted that the passive tissues were able to support the entire extensor moment demand, indicating that muscle activity was not required to support the weight of the upper body, consistent with the mechanism of flexion relaxation. The model further demonstrated that despite being inactive, spine muscles still greatly contribute to flexion relaxation by passively supporting ~47% of the extensor moment demand on the spine. Finally, there was strong agreement between the predicted active muscle moments and the recorded spine muscle activity (EMG); this strong agreement persisted when the external moment was manipulated using a pulley-system. These findings provide additional confidence that the estimated passive muscle moments are reasonably accurate throughout spine flexion.

On the Product of Complex Gaussians With Applications to Radar

The joint probability density function (pdf) of a complex vector, which is the product of a complex Gaussian scalar and a complex Gaussian vector, added to another complex Gaussian vector, is derived. The pdf, cumulative distribution function, moments, and moment generating function of the squared norm and norm of this vector are then derived. The derived result is then used to characterize the performance of energy detector (square law detector) for radar system.

On end-to-end performance of variable gain AF relayed cognitive underlay networks

ABSTRACTThe objective of this work is to analyse the performance of an underlay cognitive radio network which incorporates a variable-gain amplify-and-forward relay to enhance its performance. The system is based on extended generalised-K fading distribution and works under the constraint of interference temperature. As a result, the secondary source and the relay transmit powers will be curbed to avoid secondary signal interfering with the primary transmission when both the networks communicate simultaneously. This is the basic principle of an underlay system where both primary and secondary networks are active at the same time. The influence of fading and shadowing on the different radio links of the system is also taken into account. The analysis begins with finding the end-to-end signal-to-noise-ratio and then derives its cumulative distribution function and moment generating functions. This is followed by the derivation of the analytic closed form expressions for the outage probability, the channel capacity and the error probability of the dual-hop AF relayed underlay cognitive radio network. Numerical plots following the mathematical analysis illustrate the effects of various parameters on the system performance under the constraints of interference temperature and the secondary transmit powers.

Chemical Bonding from the Statistics of the Electron Distribution.

An introduction to the theory of chemical bonding from the point of view of the statistics of the electron distribution is presented. When atoms bind to form a molecule, their originally fixed number of electrons ceases to be a well-defined observable, and this implies that their in-the-molecule electron populations fluctuate. If a chemically meaningful definition of an atom in a molecule is assumed, the probabilities of finding a given number of electrons in each of the atoms comprising the molecule can be computed. We show in this review how the complete electron distribution function (EDF) can be used to reconstruct the basic concepts and quantities used in chemical bonding without recourse to the orbital paradigm. From the statistical point of view, which inherits Born's probabilistic interpretation of quantum mechanics, a set of atoms are bonded when their electron populations are mutually dependent. We quantify this statistical dependence by the cumulant moments of the EDF, which provide a consistent description of both two- and multi-center bonding. Particular attention is paid to building EDFs from model wavefunctions. With this, a simple bridge with orbital thinking is built. The statistical interpretation allows to easily classify all possible bonds of a given kind. We show that there are vast unexplored territories that should receive due consideration. Although building EDFs from models is easy and very instructive, the contrary is considerably more difficult. Recipes to extract chemical information from computed EDFs are also reviewed and, in all the cases, simple toy systems are used to show how the methodology works, allowing non-experts to follow easily the presentation.

Two-Sided Lindley Distribution with Inference and Applications

We propose a new distribution, called two-sided Lindley distribution. Some of its statistical properties are derived including the probability and cumulative density functions, moments and quantile function. The proposed distribution is applied to GARCH volatility model. An application on Nikke-225 index is given to demonstrate the performance of GARCH model specified under two-sided Lindley innovation distribution against to normal, Student’s-t, skew-normal and skew-T models based on the forecasting accuracy of value-at-risk. It is concluded that GARCH model with two-sided Lindley innovation distribution provides better fits than other competitive models and produce the most accurate value-at-risk forecasts among others.

Performance evaluation of energy harvesting based DF system over Nakagami-[formula omitted] fading channels in the presence of co-channel interferences

This paper presents the performance of dual-hop energy harvesting cooperative relaying system with co-channel interferences over Nakagami-m fading channels. In this system, communication between source and destination takes place through energy constrained wireless powered intermediate relay. The relay node uses time switching(TS) simultaneous wireless information and power transfer protocol to process data in different time slots. We contemplate two schemes for the dual-hop energy harvesting relaying system. In the first scheme, it is considered that cooperative path is assisted with the direct path and maximal ratio combining (MRC) and selection combining(SC) diversity techniques are employed at the destination. In second scheme, we consider only the cooperative path in the absence of direct path. We present the probability density function(PDF), cumulative distributive function(CDF) and moment generating function(MGF) of instantaneous end-to-end signal-to-interference-plus-noise ratio of the system. With the help of the these functions, closed form expressions of performance measures such as average symbol error probability (ASEP) and throughput are obtained. This paper investigates the effect of energy harvesting ratio and energy conversion efficiency on the performance of the system. It also examines the impact of channel condition and relay positioning on system performance under the influence of co-channel interferences. The exactness of our study is set by numerical simulations which assess the accuracy of the obtained analytical results.

Alterations in cellular force parameters and cell projections in Nasal polyps-derived fibroblasts

ObjectiveChronic Rhinosinusitis with Nasal Polyps (CRSwNP) is a disease that features a mechanical dysfunction involving chronic inflammation and altered tissue remodeling. In this study, we aim to evaluate the fibroblast morphology and its cellular traction force in primary fibroblasts cell cultures obtained from both healthy individuals (n=7) and patients with CRSwNP (n=8). MethodsUsing a Traction-force Microscopy we analyzed parameters of Force/Tension in fibroblasts cultures in both experimental groups. ResultsThe analysis of the Projected Area of Cell revealed that fibroblasts derived from nasal mucosa of healthy individuals have an area on average 39.24% larger than the fibroblasts obtained from the nasal polyp tissue. We also observed that the parameters directly related to the force of the cell, Max Cumulative Force and Net Contractile Moment, presented a high Force/Tension per unit of area in the fibroblasts derived from the healthy nasal mucosa (on average 41% and 52.54% higher than the fibroblasts of the nasal polyp respectively). ConclusionOur results demonstrate a cellular mechanism that may be associated with the mechanical dysfunction found in the Nasal Polyp tissue. The weak traction force of nasal polyp-derived fibroblast may, in lower dimensions, impact on the remodeling of nasal mucosa in CRSwNP.

The MW = 7.8 Earthquake of July 17, 2017 near the Commander Islands: Tectonic Position and Geodynamic Setting

The tectonic position and overall geodynamic setting, as well as the seismological characteristics and peculiarities of the aftershock process, are considered for the source of the strongest Near Island Aleutian earthquake of July 17, 2017, М W = 7.8, on the Commander Islands. It is shown that in contrast to the eastern segments of the Aleutian island arc, the subduction of the Pacific lithospheric plate beneath the Commander block is not observed. The analysis has shown that, according to the distribution of the aftershock epicenters in the form of a linear elongated narrow zone with a length of about 400 km, the seismic source occupied almost entire northern slope of the Commander Island rise and spread in the Bering fault zone. It spanned the whole of this seismogenic zone up to the transverse structure west of the Near Islands (Attu islands). The focal mechanism solutions and the pattern of displacements in the sources of the main shock, as well as the strongest foreshocks and aftershocks, suggest that the slip in the source was an almost pure right-lateral shear. The aftershock process of the earthquake on July 17 developed quite feebly for an earthquake of this magnitude. Besides, it has two specific features distinguishing it from the aftershock processes of most of the Kuril-Kamchatka earthquakes: (1) a low release of the cumulative scalar seismic moment (M 0cum aft ), which, according to different estimates, made up from 0.75 to 1.0% of the main-event seismic moment (M 0me ); and (2) a very slow growth of the deficit in the release of seismic moment (M 0 ). At the same time, the duration of the quasi-stationary phase of the M 0cum release in the aftershocks, which is estimated at approximately half-a-year and which took a considerable span of the total length of the aftershock process from this earthquake, appears to be untypically long. These features of the aftershock process of the Near Island Aleutian earthquake of July 17, 2017 distinguish it from the aftershock processes peculiar to most of the strong Kuril–Kamchatka earthquakes. Overall, its source can be considered as a transform one between the two Benioff zones, the Aleutian and Kuril–Kamchatka ones, rather than as a subduction source characteristic of the last two zones.

Heterogeneous Behavior of the Campotosto Normal Fault (Central Italy) Imaged by InSAR GPS and Strong-Motion Data: Insights from the 18 January 2017 Events

On 18 January 2017, the 2016–2017 central Italy seismic sequence reached the Campotosto area with four events with magnitude larger than 5 in three hours (major event MW 5.5). To study the slip behavior on the causative fault/faults we followed two different methodologies: (1) we use Interferometric Synthetic Aperture Radar (InSAR) interferograms (Sentinel-1 satellites) and Global Positioning System (GPS) coseismic displacements to constrain the fault geometry and the cumulative slip distribution; (2) we invert near-source strong-motion, high-sampling-rate GPS waveforms, and high-rate GPS-derived static offsets to retrieve the rupture history of the two largest events. The geodetic inversion shows that the earthquake sequence occurred along the southern segment of the SW-dipping Mts. Laga normal fault system with an average slip of about 40 cm and an estimated cumulative geodetic moment of 9.29 × 1017 Nm (equivalent to a MW~6). This latter estimate is larger than the cumulative seismic moment of all the events, with MW > 4 which occurred in the corresponding time interval, suggesting that a fraction (~35%) of the overall deformation imaged by InSAR and GPS may have been released aseismically. Geodetic and seismological data agree with the geological information pointing out the Campotosto fault segment as the causative structure of the main shocks. The position of the hypocenters supports the evidence of an up-dip and northwestward rupture directivity during the major shocks of the sequence for both static and kinematic inferred slip models. The activated two main slip patches are characterized by rise time and peak slip velocity in the ranges 0.7–1.1 s and 2.3–3.2 km/s, respectively, and by ~35–50 cm of slip mainly concentrated in the shallower northern part of causative fault. Our results show that shallow slip (depth < 5 km) is required by the geodetic and seismological observations and that the inferred slip distribution is complementary with respect to the previous April 2009 seismic sequence affecting the southern half of the Campotosto fault. The recent moderate strain-release episodes (multiple M~5–5.5 earthquakes) and the paleoseismological evidence of surface-rupturing events (M~6.5) suggests therefore a heterogeneous behavior of the Campotosto fault.

Differences in spinal moments, kinematics and pace during single-task and combined manual material handling jobs

This study compared the spinal moments (i.e., peak and cumulative moments acting on the L5/S1 joint), kinematics (i.e., peak trunk and knee angles) and work pace of workers, when either removing a box from a shelf or depositing a box on a shelf, under two conditions: as a single task or as part of a combined task. An experiment was conducted, in which the subjects performed the tasks and were recorded using a motion capture system. An automated program was developed to process the motion capture data. The results showed that, when the removing and depositing tasks were performed as part of a combined task (rather than as single tasks), subjects experienced smaller peak and cumulative spinal moments and they performed the tasks faster. The results suggest that investigations into the separate tasks that comprise a combination have a limited ability to predict kinematics and kinetics during the combined job.

Fast Running Does Not Contribute More to Cumulative Load than Slow Running.

As running speed increases there are concomitant changes in loads associated with tibial stress fracture risk. Runners often include multiple speeds in their training, but the effect of speed distribution on load accumulation is unknown. We studied how running at different proportions of speed within a given running distance affects the cumulative loading of the vertical average loading rate, cumulative peak absolute tibial free moment, and cumulative peak axial tibial load. These loads were compared between two proportions of speed: running all distance at normal self-selected speed, and running the same distance at a combination of slow/fast speeds with the same average speed as normal. Also, the contributions of slow and fast running to the combined condition were compared. Forty-three recreational runners (age, 18-49 yr; 29 female, 14 male) ran around a 50-m indoor track for three laps each at self-selected slow, normal, and fast speeds. Per-step peak loads and cumulative loads per kilometer were calculated at each speed and for each speed distribution, respectively. Only cumulative vertical average loading rate was lower at normal speed compared with the slow/fast speed combination. The contribution of fast speed running to cumulative tibial load was less than the contribution of slow speed running. Running at a combination of slow and fast speeds, rather than a single moderate speed, increased cumulative vertical average loading rate but not cumulative tibial load or free moment. Fast running can be included in a training program without necessarily increasing the cumulative load. Total distance and average speed may not be sufficient information to estimate cumulative load from running training.

Gait- and Posture-Related Factors Associated With Changes in Hip Pain and Physical Function in Patients With Secondary Hip Osteoarthritis: A Prospective Cohort Study

ObjectiveTo identify gait- and posture-related factors associated with changes in hip pain and physical function in patients with hip osteoarthritis (OA). DesignProspective cohort study. SettingClinical biomechanics laboratory of a university. ParticipantsConsecutive sampling of female patients with mild-to-moderate secondary hip OA (N=30). Main Outcome MeasuresHip pain (visual analog scale) and physical function (physical component summary of the Medical Outcomes Study 36-Item Short-Form Health Survey) were measured at baseline and 12 months later. With changes in hip pain and physical function as dependent variables, linear regression analyses were performed with gait- and posture-related factors as independent variables with and without adjustment for age, joint space width, and hip pain or physical function at baseline. Posture-related factors included angles of thoracic kyphosis, lumbar lordosis, sacral inclination, spinal inclination, and spinal mobility. Gait-related factors were walking speed, steps per day, joint angles, external hip joint moment impulses, and daily cumulative hip moments. ResultsMultiple linear regression analyses showed that limited hip extension (adjusted standardized B coefficient [95% confidence interval]: −0.52 [−0.88 to −0.17]) and limited external rotation angles (−0.51 [−0.85 to −0.18]) during walking were associated with the worsening of hip pain. An increased thoracic kyphosis (−0.54 [−0.99 to −0.09]), less sacral anterior tilt (0.40 [0.01-0.79]), reduced thoracic spine mobility (0.59 [0.23-0.94]), less steps per day (0.53 [0.13-0.92]), and a slower walking speed (0.45 [0.04-0.86]) were associated with deterioration in physical function. ConclusionsGait- and posture-related factors should be considered when assessing risk and designing preventive interventions for the clinical progression of secondary hip OA.

Earthquake july 17, 2017, Mw = 7.8 near the Komandorsky islands and strong seismic manifestations in the western segment of Aleut island arc

The tectonic position, seismological characteristics and features of the aftershock process of the source of the strongest Near-Aleutian earthquake on July 17, 2017 on the Commander Islands with Мw = 7.8 are considered. The analysis showed that the seismic source according to the distribution of aftershock epicenters in the form of a linearly elongated narrow zone with a length of about 400 km almost completely occupied the northern slope of the Commander island elevation and was located in the Bering fault zone. It covered the whole of this seismic-generating zone up to the transverse structure to the west of the Near Islands (Attu is.). In accordance with the focal mechanisms solution and the nature of the displacements in the foci of the main shock, the strongest foreshocks and aftershocks, the shift in the source was an almost pure right-sided shift. The aftershock process of the July 17 earthquake developed quite enough inertly for an earthquake of such strength. In addition, it has two features in comparison with the aftershock processes of most of the Kuril-Kamchatka earthquakes: 1) low release of the cumulative scalar seismic moment (M0cum aft), which according to various estimates was from 0.75% to 1.0% of the seismic moment of the main shock (M0me); 2) a very slow increase in the deficit in the release of the seismic moment (M0). At the same time, the duration of the quasi-stationary phase of M0cum release in aftershocks, estimated at about ½ year and covering a significant part of the duration of the entire aftershock process of this earthquake, seems unusually long. These features of the aftershock process of the Middle Aleutian earthquake on July 17, 2017 distinguish it from the aftershock processes characteristic of most strong Kuril-Kamchatka earthquakes. In general, its source can be considered as a transform between the two Benioff zones – Aleutian and Kuril-Kamchatka, and not subduction, that is characterise the last two.

Earthquake july 17, 2017, Mw = 7.8 near the Komandorsky islands and strong seismic manifestations in the western segment of Aleut island arc

The tectonic position, seismological characteristics and features of the aftershock process of the source of the strongest Near-Aleutian earthquake on July 17, 2017 on the Commander Islands with Мw = 7.8 are considered. The analysis showed that the seismic source according to the distribution of aftershock epicenters in the form of a linearly elongated narrow zone with a length of about 400 km almost completely occupied the northern slope of the Commander island elevation and was located in the Bering fault zone. It covered the whole of this seismic-generating zone up to the transverse structure to the west of the Near Islands (Attu is.). In accordance with the focal mechanisms solution and the nature of the displacements in the foci of the main shock, the strongest foreshocks and aftershocks, the shift in the source was an almost pure right-sided shift. The aftershock process of the July 17 earthquake developed quite enough inertly for an earthquake of such strength. In addition, it has two features in comparison with the aftershock processes of most of the Kuril-Kamchatka earthquakes: 1) low release of the cumulative scalar seismic moment (M0cum aft), which according to various estimates was from 0.75% to 1.0% of the seismic moment of the main shock (M0me); 2) a very slow increase in the deficit in the release of the seismic moment (M0). At the same time, the duration of the quasi-stationary phase of M0cum release in aftershocks, estimated at about ½ year and covering a significant part of the duration of the entire aftershock process of this earthquake, seems unusually long. These features of the aftershock process of the Middle Aleutian earthquake on July 17, 2017 distinguish it from the aftershock processes characteristic of most strong Kuril-Kamchatka earthquakes. In general, its source can be considered as a transform between the two Benioff zones – Aleutian and Kuril-Kamchatka, and not subduction, that is characterise the last two.