Bilateral Rupture Research Articles

Irregular rupture propagation and geometric fault complexities during the 2010 Mw 7.2 El Mayor-Cucapah earthquake

The 2010 MW 7.2 El Mayor-Cucapah, Mexico, earthquake ruptured multiple faults with different faulting mechanisms. Resolving the earthquake rupture process and its relation to the geometric fault complexities is critical to our understanding of the earthquake source physics, but doing so by conventional finite-fault inversion is challenging because modelling errors due to inappropriate assumptions about the fault geometry distort the solution and make robust interpretation difficult. Here, using a potency density tensor approach to finite-fault inversion, we inverted the observed teleseismic P waveforms of the 2010 El Mayor-Cucapah earthquake to simultaneously estimate the rupture process and the fault geometry. We found that the earthquake consisted of an initial normal faulting rupture, which was followed by a strike-slip bilateral rupture towards the southeast and northwest that originated on the northwest side of the epicentre. The southeastern rupture propagated back through the initial rupture area, but with strike-slip faulting. Although the northwestern rupture propagated across the left step in the Puerta fault-accommodation zone, the rupture was temporarily stalled by the associated change of the fault geometry. These results highlight the irregular rupture process, which involved a back-propagating rupture and fluctuating rupture propagation controlled the complexity of the fault system.

Dorsal scapular displacement (flying scapula) in a heifer

AbstractDorsal scapular displacement, or flying scapula, is a rare condition characterised by sinking of the thorax between the forelimbs and protruding of the scapula above the thoracic vertebrae with the impression of a humpback appearance of the affected individual. The aetiology is still a matter of controversy. A 10‐month‐old heifer was presented with a history of sudden onset of gait abnormality and reluctance to stand and walk after being turned out to a spring pasture following the winter housing period. Clinical examinations revealed signs consistent with flying scapula. Whole‐blood selenium concentration and erythrocyte glutathione peroxidase activity were within the marginal status. Vitamin E level in serum was within the reference range. We proposed that the condition resulted from damage and bilateral rupture of the serratus ventralis muscle due to dystrophic myodegeneration in a selenium‐deficient individual exacerbated by walking long distances and unaccustomed physical activity after winter housing.

Source Process Featuring Asymmetric Rupture Velocities of the 2021 Mw 7.4 Maduo, China, Earthquake from Teleseismic and Geodetic Data

AbstractOn 21 May 2021, an Mw 7.4 left-lateral strike-slip earthquake occurred within the Bayan Har block in the Tibetan plateau. To learn about the source rupture process, we collected the teleseismic waveforms and utilized the backprojection method to investigate the rupture kinematics of the earthquake. The results indicate that the earthquake was a bilateral rupture event with asymmetric rupture velocities. The rupture velocity in the east of the epicenter was uniform and in the range of 2.72–3.67 km/s, whereas, in the west, it was in the range of 1.39–1.78 km/s in the first 20 km and then increased to 2.82–3.17 km/s. The slip distribution constrained by the Interferometric Synthetic Aperture Radar and Global Positioning System displacements clearly reveals kinematic coseismic slip in greater detail, which makes up for the limitations of the backprojection method. Two main asperities in the east verify the results of the backprojection method. The rupture depth in the west was slightly shallower than that in the east, which may be the reason for the asymmetry of rupture velocities. The initial rupture point was updated based on the asymmetric velocities and geodetic slip distribution. The multiple-point-source moment tensors based on the rupture velocities and new initial rupture point not only match the fault geometries determined by relocated aftershocks but also fit well with the released energy distribution, which proves the asymmetry of rupture velocities.

Rotura bilateral do tendão rotuliano (clínica case)

Simultaneous bilateral rupture of the patellar tendon is a rare entity. In this paper we describe the case of a bilateral rupture of the patellar tendon because of an indirect trauma to both knees. He was a healthy individual with no important identifiable risk factors. Surgical treatment consisted of tendon reinsertion through longitudinal bone tunnels in the patella, temporarily protected with discharge cerclage in the form of a tension band. He maintained a short period of immobilization with articulated knee braces, with a progressive increase in the allowed flexion. Ten weeks after the operation, the discharge cerclage was removed. The return to sports activity was allowed six months after surgery. In this work, we also make a brief review of the etiopathogenic factors identified in the literature.

Bilateral patellar tendon rupture: a case report

<p>Bilateral patellar tendon rupture is a rare injury, usually associated with systemic disease or chronic medication side effect. Early diagnosis and prompt surgical repair are essential to achieve good functional outcomes. The authors report a case of a 44-year-old male with history of multiple urinary tract infection treated with fluoroquinolones who sustained spontaneous simultaneous bilateral patellar tendon rupture. Patient underwent bilateral transosseus tendon repair with autologous semitendinosus augmentation. Nine months after surgery, the patient was able to walk without pain and unassisted, had a normal range of motion in both knees and performed his daily activities without limitation. Surgical treatment of patellar tendon rupture is recommended to allow prevention of extensor mechanism disfunction sequelae. Transosseus tendon repair with autologous semitendinosus augment plasty is a valid surgical technique for treatment of this pathology with biomechanical and literature support.</p>

Bilateral spontaneous Achilles tendon rupture in a pregnant patient

Joint Diseases and Related Surgery (JDRS), the official journal of the Turkish Joint Diseases Foundation, is an international, peer-reviewed, immediate open access journal. All published articles in JDRS has been free for everyone, without embargo, since 1990.

Coseismic surface ruptures, slip distribution, and 3D seismogenic fault for the 2021 Mw 7.3 Maduo earthquake, central Tibetan Plateau, and its tectonic implications

The 2021 Mw 7.3 Maduo earthquake, which hit the high mountain area of the internal Bayan Har Block in the central Tibetan Plateau, generated a ~ 154 km-long, nearly E-W-striking surface rupture zone. Field observations indicate prominent surface breaks characterized by discontinuous shear faults, en echelon tensional fissures, and mole track structures, revealing a dominantly left-lateral strike-slip motion with a maximum sinistral offset of ~2.7–2.8 m and general offset of ~1.0–1.5 m. The west part of the Maduo surface rupture zone occurred along the pre-existing Jiangcuo fault. Its east portion cut through some WNW-trending tectonics, indicating a previously unknown fault. The epicenter and slip distribution show a bilateral rupture for the Maduo quake. The complex 3D geometry of the Maduo seismogenic fault has controlled the occurrence of aftershocks and the multimodal distribution of coseismic displacements. The abnormally long Maduo surface rupture zone suggests that the rupture area-magnitude relationship might be more applicable than the rupture length-magnitude relationship for the magnitude estimation of a paleo-event. The occurrence of the Maduo earthquake challenges the active block model which used to predict little or no slip partitioning and large earthquakes in the block interior. A reappraisal of seismic hazard along intra-block faults with low strain rates is needed, especially across densely populated regions.

Concomitant Use of Single Suture Anchor and Transosseus Repair Provide Optimal Results in Simultaneous Bilateral Quadriceps Tendon Rupture: A Case Report

Introduction
 Bilateral quadriceps tendon rupture is a rare condition and often associated with underlying medical comorbidities such as chronic renal insufficiency. This case report is aimed to evaluate the surgical outcome using the combination of suture anchor and transosseus repair technique.
 
 Presentation of Case
 Presenting a 54-year-old male who sustained simultaneous bilateral quadriceps tendon rupture with history of right nephrectomy and chronic kidney disease requiring intermittent hemodialysis. He came with sudden bilateral knee pain, history of falling, and inability to walk since three weeks before admission to the hospital. Tenderness above the superior pole on both patella, accompanied with slight swelling and no active range of motion (ROM) of either knee joint was found on physical examination. Complete rupture of the quadriceps tendon of both knees at their osseus-tendon junction were revealed on magnetic resonance imaging (MRI).
 
 Discussion
 Recent literatures suggested that transosseus technique offers the safest and more stable tendon reattachment, while suture anchor provides biomechanical superiority. We tried to combine these advantages by incorporating both methods. Progressive active knee motion exercise was performed shortly after using the Kocher slab for 2 weeks.Subsequently, the patient can achieve painless, active extension and active 90°-120° knee flexion 1 month post-operatively.
 
 Conclusion
 The application of a single suture anchor with transosseus repair in quadriceps tendon rupture led to an optimal outcome, improved stability, and earlier rehabilitation.

The 2021 Mw 7.4 Madoi Earthquake: An Archetype Bilateral Slip‐Pulse Rupture Arrested at a Splay Fault

AbstractWe combine measurements of ground deformation from Synthetic Aperture Radar images, high‐rate Global Navigation Satellite System and tele‐seismic waveforms to study the rupture kinematics of the Madoi Earthquake, which occurred in eastern Tibet on 21 May 2021 and reached a moment magnitude Mw 7.4. The data show nearly pure left‐lateral motion along a 170 km long rupture and a total duration of 36 s. The earthquake initiated near the middle of the main segment and evolved in a bilateral slip pulse rupture which propagated at a sub‐Rayleigh speed of 2.6–2.8 km/s. In our model, slip is concentrated at depth of less than ∼15 km and reaches a maximum of 4.2 m. The rupture arrested ∼10 s after branching on the extensional splay faults at both extremities. The branching onto the splay faults and the eventual arrest of the rupture is used to provide constraints on the fault frictional properties.

Kinematics of the 30 October 2020 Mw 7.0 Néon Karlovásion (Samos) earthquake in the Eastern Aegean Sea: Implications on source characteristics and dynamic rupture simulations

We resolve source mechanism and rupture process for the Néon Karlovásion, Samos Mw 7.0 earthquake that struck Greek-Turkish border regions on 30th October 2020 acquired from kinematic joint inversion of teleseismic body-waves and near-field strong ground-motion waveforms. The optimal kinematic finite-fault slip model indicates a planar E-W striking north-dipping normal faulting mechanism with strike ϕ = 270° ± 5°; dip δ = 35° ± 5°; rake λ = −94° ± 5°; centroid depth h = 11 ± 2 km; duration of the source time function STF = 26 s and seismic moment Mo = 3.34 × 1019 Nm equivalent to Mw = 7.0. Our final finite- fault slip models exhibit two main asperities within a depth range from ~20 km to the surface. The dynamic rupture model exposes an initial heterogeneous stress distribution with variations up to 25 MPa. The near-field strong motion waveforms constrained the slip model suggesting up-dip and westward propagation of the bilateral rupture pattern with a maximum slip of 3.2 m, illuminated by back-projection (BP) analysis. The high-frequency (HF) back-projected rupture showed a predominantly E-W striking component (~75%) with directivity of 277° that propagates to the surface along a 60 km long and 24 km wide fault plane in 20 s at a slower speed range of 1.0–2.0 km/s. This well constrains the coseismic slip region where the aftershock sequence confirms distributed deformation. Our back-projection analyses elucidates a dominant HF rupture stage (0–13 s) tracked first on the epicentre area and further along the downdip in the region of maximum coseismic slip indicating ~15 km of persistent rupture. The latter HF emissions (13–20 s) remark a speed of about 3.0 km/s and a westward extension of the rupture up to 30 km from the preceding rupture segment to shorelines at the northeast of the Ikaria Island.

A case of bilateral Achilles tendon spontaneous rupture in a hemodialysis patient: Who is the real culprit? Acidosis? Or hyperparathyroidism?

Patients who are on regular hemodialysis and who have advanced renal failure but have not yet started on renal replacement therapy have a high risk of tendon rupture, although this is a rare situation. We reported a case of 55-year-old male patient who had been on regular hemodialysis for the past 10 years. He presented with a sudden onset of pain and swelling in the left posterior ankle while climbing stairs. Ultrasonography revealed a complete disruption of the Achilles tendon, which was surgically repaired. His medical history was remarkable for the right Achilles tendon rupture a year ago. Investigations revealed tertiary hyperparathyroidism with chronic metabolic acidosis and high β-2 macroglobulin. With surgical repair, physiotherapy, and parathyroidectomy, the patient regained full active mobility. This case emphasized the importance of high parathyroid hormone level, metabolic acidosis, and high β-2 macroglobulin in the pathogenesis of tendons ruptures. Keywords: Achilles tendon, Hemodialysis, High β-2 macroglobulin, Hyperparathyroidism, Rupture.

Early weight-bearing and functional treatment with stability boots after surgical repair of bilateral Achilles tendon rupture: A case report

Early weight-bearing and functional treatment with stability boots after surgical repair of bilateral Achilles tendon rupture: A case report

Simultaneous Bilateral Quadriceps Femoris Tendon Rupture: Case report

Introduction: Simultaneous bilateral quadriceps tendon rupture is a very rare injury that may be associated with systemic illnesses or drugs. We present a case of bilateral quadriceps tendon rupture in a patient with no identifiable risk factors. 
 Case: Sixty seven year old male patient presented to emergency room with bilateral knee pain after trip and fall from 2 steps on his knees. His physical exam revealed bilateral suprapatellar swelling and tenderness with palpation on both knees and he could not fully actively extend knees. Magnetic resonance imaging revealed bilateral quadriceps tendon rupture. Both knees were immobilized with long leg cast in full extension. Early operative treatment was offered. 
 Conclusion: Diagnosis may be delayed in bilateral quadriceps tendon rupture. Since it is a rare injury emergency medicine physicians should be familiar with symptoms and signs of it to diagnose it early and prevent disability.

Traumatic Simultaneous and Bilateral Rupture of the Quadriceps Tendon in a Bodybuilder Patient

Simultaneous and bilateral rupture of the quadriceps tendon is a rare condition. We present the case of a 38-year male bodybuilder patient with a traumatic simultaneous and bilateral rupture of the quadriceps tendon.

Bilateral Testicular Evisceration Sequel to Trauma: Challenges of Management in Emergency Department

Introduction The Genitourinary (GU) tract injury is rare with an annual incidence of less than one percent. We present a rare case of traumatic degloving injury of male external genitalia with complete evisceration of bilateral testicles following motor vehicle accident. Case description 29-year-old lorry driver was brought to Emergency department following head-on crash of his lorry into a ravine resulting in chest, abdomen and pelvis slamming onto dashboard. The driver was trapped for 4.5 hours. On arrival, he was conscious but hemodynamically unstable. Clinical examination and Focused Assessment with Sonography in Trauma (FAST) was suggestive of left pneumothorax and no evidence of intraabdominal injury. Chest tube was inserted. Genital examination showed scrotal degloving wound with complete evisceration of bilateral testis. He also sustained open fracture of right tibia, fibula and left inferior pubic rami fracture. Upon stabilization, was sent for operation and intraoperatively found to have bilateral testicular rupture. He underwent scrotal exploration, and bilateral orchidopexy. Postoperatively, multiple dialysis sessions were done for rhabdomyolysis. Hormonal study yielded low levels of testosterone. He was discharged home after 2 weeks with testosterone pills. Discussion Challenges in Emergency Department setting would be prompt identification and management of life-threatening injuries along simultaneous management of degloving external genitalia injury and associated injuries. FAST and extended FAST play a key role in managing life threatening conditions. Conclusion Total evisceration of bilateral testis injury are rare. Although not life threatening, should be treated promptly and thoroughly in order to avoid long-term functional and psychological damage.

The 30 October 2020, MW = 7.0, Samos earthquake: aftershock relocation, slip model, Coulomb stress evolution and estimation of shaking

We study the major MW = 7.0, 30 October 2020, Samos earthquake and its aftershocks, by calculating improved locations using differential travel times and waveform cross-correlations. We image the rupture of the mainshock using local strong motion data, and we examine the Coulomb stress evolution prior to the mainshock, as well as the coseismic stress changes. Lastly, we estimate the produced shaking using all the available information from strong motion data and testimonies. Earthquake relocations reveal the activation of the E-W oriented Kaystrios fault, in the North basin of Samos with a possible extension to the West. The kinematic rupture inversion suggests non-uniform bilateral rupture on a ∼60 km × ∼20 km fault area, with the main rupture propagating towards the West and maximum slip up to approximately 2.5 m. Improved locations of the aftershock sequence are anti-correlated with areas of maximum slip on the fault surface. Similarly, the Coulomb stress change calculations show that only off-fault earthquake clusters are located within lobes of increasing positive static stress changes. This observation is consistent with assuming a fault area of either uniform slip, or variable slip according to the obtained slip model. Both scenarios indicate typical stress patterns for a normal fault with E-W orientation, with stress lobes of positive ∆CFF increments expanding in E-W orientation. In the case of the variable slip model, both negative and positive stress changes show slightly larger values compared to the uniform slip model. Finally, Modified Mercalli Intensities based on the fault model obtained in this study indicate maximum intensity (VII +) along the northern coast of Samos Ιsland. Spectral acceleration values at 0.3 s period also demonstrate the damaging situation at Izmir.

Collapse fragility due to near-field directivity ground motions: Influence of component, rupture distance, hypocenter location

The variability in source characteristics induces spatial variability in the characteristics of near-field ground motion intensities which in turn impacts the fragility behaviour of structures. The study aims to quantify such variability in fragility curves of low-rise structures with a natural period of 0.2 sec with change in nucleation asperity, a source parameter of earthquake rupture corresponding to (Mw ⋍ 7). Four rupture scenarios are considered which differ from each other based on the position of nucleation asperity. The rupture scenarios are termed as bilateral, partial bilateral, partial unilateral, and unilateral, respectively. For bilateral rupture, the nucleation asperity is placed exactly in the middle of the fault face. In contrast, in the unilateral case, the nucleation asperity is placed at the end of the fault. Additionally, fragility curves corresponding to each horizontal component (fault-parallel and fault-normal) of ground motions at stations with varying rupture distances are also highlighted. The study is also extended to evaluate structures’ fragility behaviour with a natural period of 0.6 sec, 1 sec and 4 sec. Additionally bi-directional response to the simulated ground motions were emphasized.

Response of inelastic SDOF systems subjected to dynamic rupture simulations involving directivity and fling step

Directivity is a phenomenon perceived during fault ruptures wherein the ground motion and spectral response in the direction of the rupture is more significant than in any other direction. The objective of this study is to evaluate the variability in characteristics of near-fault ground motions as well as the ductility demand on structures due to directivity based on simulations of strike-slip earthquake events by employing SPECFEM3D, a physics-based ground motion simulation code. To understand the finite fault propagation effect, a source effect, the vertical strike-slip fault is considered to be embedded in an elastic half-space, to prevent the influence of path and site effects. Two scenarios are designed based on the positioning of nucleation asperity (NA): (1) in the middle of the fault face to simulate bilateral (BL) rupture and (2) shifted to one end for the case of unilateral (UL) rupture. The ground motions at near-fault stations, located in a racetrack configuration around the surface trace of the fault, are analyzed. In addition to a high spectral content in the forward directivity stations as a result of UL rupture, directivity velocity pulses identified in the fault-normal components are higher than the fling step velocity pulses in the fault-parallel component for the racetrack stations considered. Furthermore, the study examines the correlation between ductility demands computed based on elastoplastic rheology with direct point parameter and ground motion intensity measures for directivity and fling step stations.

Differences in risk factors exist for the occurrence of bilateral versus unilateral distal biceps tendon ruptures: a systematic review

ImportanceDistal biceps rupture is a debilitating injury that is increasing in incidence. A subset of patient experiences this injury on both sides, simultaneously or at separated times. Previous studies have evaluated the incidence and risk factors of unilateral distal biceps rupture. However, little is known about the risk factors for bilateral distal biceps rupture.AimsThis aims of this study were to determine risk factors for bilateral distal biceps rupture and to compare these to the known risk factors for unilateral rupture.Evidence reviewA systematic review of literature was conducted using five databases, producing a total of 1183 papers. After the review process, 31 papers with data bilateral distal biceps tendon ruptures were included.FindingsThe 31 papers included a total of 2234 patients with 2366 ruptures. Patients with a bilateral rupture were younger than patients with unilateral ruptures (45.8 vs 48.8 years old). Women made up a larger percentage of patients with bilateral ruptures (6.8% vs 4.0%). Bilateral injuries occurred most commonly during heavy lifting or falls, whereas forced extension of the arm was the most frequently reported injury mechanism reported with unilateral ruptures. Tobacco used was more common in patients with bilateral ruptures (24.4% vs 6.8%). Labour-intensive occupations and anabolic steroid use did not appear to increase the risk of a bilateral rupture. Pooling of the data was not possible due to heterogeneity of the included studies.ConclusionsWhile differences in risk factors between patients with unilateral and bilateral ruptures were observed, there was too great of a degree of heterogeneity among the studies to perform a meta-analysis of the data.Level of evidenceSystematic review; level III evidence.

Neuro‐Fuzzy Kinematic Finite‐Fault Inversion: 2. Application to the Mw6.2, August/24/2016, Amatrice Earthquake

AbstractIn this article, we validate the neuro‐fuzzy kinematic finite‐fault inversion method by studying the rupture process of the , Aug/24/2016, Amatrice, central Italy, earthquake. We jointly invert three different datasets to infer the spatio‐temporal slip distribution, namely static and high‐rate GNSS data (<= Hz) and strong‐motion data ( Hz). Each data set is used to constrain a different frequency range of the source model, depending on the sensitivity of the data set. The inferred slip shows a slow nucleation phase at shallow depths of 3–4 km, followed by a bilateral rupture that forms two asperities, one to the NW (Norcia) and another to the SE (Amatrice) of the hypocenter. Our inferred slip is compared with those previously obtained using well‐established methods. In order to select an adequate number of fuzzy basis functions, we propose two alternative procedures, which yield the same general slip features. The first approach consists of ensuring that the inverse problem is formally over‐determined and uses the same number of basis functions at all frequencies. The second approach is based on a maximum‐likelihood analysis of the model misfit and selects a different number of basis functions for each frequency. The maximum‐likelihood approach allows for more basis functions at high frequencies, where more detail in the spatial slip distribution is needed. The solution obtained with the maximum‐likelihood approach provides a more physically plausible source time function, which shows less back slip artifacts. The accurate prediction of high‐rate GNSS traces not used in the inversion attests the robustness of the inferred slip model.