Lower Portion Rupture of a Thrust Fault during the 2017 Mw 6.3 Jinghe Earthquake: Implications to Seismic Hazards in the Tian Shan Region

The 2017 Mw 6.3 Jinghe earthquake represents one of the few large earthquakes that are well recorded by seismic instruments and Interferometric Synthetic Aperture Radar (InSAR) observations in the seismically active Tian Shan region. In this study, we use the rupture fault solution (dip, dip direction, and slip sense) from seismologic and InSAR results, along with analysis of our collected surface mapping data, to determine the subsurface fault-plane geometry of the seismogenic Jinghenan fault. This geometric model, integrated with the coseismic slip distribution from seismologic and InSAR data, reveals that: (1) the Jinghenan fault extends downward from the land surface at a dip of ∼46° S (upper ramp), then bends to ∼42° S (lower ramp) at the depth of 9–13 km; (2) the coseismic rupture is confined within the Jinghenan lower ramp, and its upper limitation is approximately coincident with the fault-bend location. This coseismic rupture pattern and seismic behavior can be broadened to other active thrust faults within the Tian Shan, suggesting that, during moderate-strong earthquakes, such faults may only rupture partially in the down-dip extension, and the unruptured fault portion remains to pose high-seismic risk in the future.

Standard MRI May Not Predict Specific Acute Anterior Cruciate Ligament Rupture Characteristics

Background: There has been renewed interest in the concept of anterior cruciate ligament (ACL) suture repair (ACLSR). Morphologic characteristics of the ruptured ACL remnant play a role in deciding whether a patient is eligible for ACLSR. However, no classification of these characteristics of ACL rupture on magnetic resonance imaging (MRI) scans has yet been compared with intraoperative findings in the context of ACLSR. Purpose: To investigate the value of using preoperative MRI to predict specific characteristics of acute complete ACL rupture. Study Design: Cohort study (diagnostic); Level of evidence, 2. Methods: A total of 25 patients were included. Two radiologists classified ACL rupture location and pattern on preoperative 1.5-T MRI scans with a standard sequence; the results were compared with the corresponding findings at arthroscopy conducted by a single surgeon. The agreement between the MRI and surgical findings was calculated using Cohen κ values. Furthermore, the reliability coefficients of the MRI classifications within and between radiologists were calculated. Results: The agreement between MRI classification and arthroscopic findings for ACL rupture location was slight (Cohen κ, 0.016 [radiologist 1] and 0.087 [radiologist 2]), and for ACL rupture pattern, this was poor to slight (Cohen κ, <0 and 0.074). The intraobserver reliability of MRI classification for ACL rupture location was moderate for radiologist 1 and slight for radiologist 2 (Cohen κ, 0.526 and 0.061, respectively), and for ACL rupture pattern, this was slight for radiologist 1 and 2 (Cohen κ, 0.051 and 0.093, respectively). The interobserver reliability of MRI classification for ACL rupture location and pattern was slight between radiologists (Cohen κ, 0.172 and 0.040, respectively). Conclusion: In the current study, we found poor to slight agreement between MRI classification and arthroscopic findings of specific ACL rupture characteristics. In addition, the intra- and interobserver reliability for MRI classification of the ACL rupture characteristics was slight to moderate.

TA Rupture Assessment Analysis – are Our "GOLD-Standards“ of Tendon Repair Valid?

Background: Current studies showed that operative treatment has advantages in comparison to conservative treatment for acute Achilles tendon ruptures. The gold standard therapy in our clinic is the operative treatment with the four strand Adelaide suture. The goal of this study is to evaluate which suture material (a) B Braun; MonoMax, b) Ethicon; PDS CTX) is more appropriate for Achilles tendon suture.Methods: Ten pairs of fresh frozen Achilles tendons were obtained from human donors aged 41 – 85. The tendons were fixed on a testing machine and loaded until failure. The goal of this setup was to create a natural rupture pattern. The ruptured tendons were sutured either with BB or PDS and again loaded until failure.The failure mode in all sutured tendons was a pullout of the suture material through the tendon fibres.Results: The ruptures occurred on different locations. The maximal forces in the sutured tendons occurring at the rupture were for the BB-suture between 144 N and 232 N (Mean 197 (SD 67) N) and for the PDS-suture between 158 N and 226 N (Mean 194(SD 70) N). The failure mode in all sutured tendons was a pullout of the suture material through the tendon fibres.Conclusion: Due to the failure mode we are not able to evaluate which suture material is better to use for the Achilles tendon repair with the Adelaide suture. Either the Adelaide suture is not an appropriate suture technique for Achilles tendon repair or the natural rupture pattern has in comparison to the in vitro rupture patterns constructed by sharp dissection a bigger influence on the pullout strength of suture techniques than we thought. This would mean that probably the data from most in vitro studies are not applicable for daily life.

Earthquake Environmental Effects of the 1992 MS7.3 Suusamyr Earthquake, Kyrgyzstan, and Their Implications for Paleo-Earthquake Studies

Large pre-historical earthquakes leave traces in the geological and geomorphological record, such as primary and secondary surface ruptures and mass movements, which are the only means to estimate their magnitudes. These environmental earthquake effects (EEEs) can be calibrated using recent seismic events and the Environmental Seismic Intensity Scale (ESI2007). We apply the ESI2007 scale to the 1992 MS7.3 Suusamyr Earthquake in the Kyrgyz Tien Shan, because similar studies are sparse in that area and geological setting, and because this earthquake was very peculiar in its primary surface rupture pattern. We analyze literature data on primary and secondary earthquake effects and add our own observations from fieldwork. We show that the ESI2007 distribution differs somewhat from traditional intensity assessments (MSK (Medvedev-Sponheuer-Karnik) and MM (Modified Mercalli)), because of the sparse population in the epicentral area and the spatial distribution of primary and secondary EEEs. However, the ESI2007 scale captures a similar overall pattern of the intensity distribution. We then explore how uncertainties in the identification of primary surface ruptures influence the results of the ESI2007 assignment. Our results highlight the applicability of the ESI2007 scale, even in earthquakes with complex and unusual primary surface rupture patterns.

Effect of Flat Heat Pipe on the Properties of the FSW Joint

Friction stir welding (FSW) joint is characterized with asymmetric gradient in three dimensions. The purpose of this thesis is trying to find the effective methods to improve the microstructure and strength of AZ31 magnesium alloy joint of FSW. In order to achieve this aim, one heat pipes was designed and applied to the FSW process. Using different cooling methods, FSW experiments were carried out in air and under the conditions of heat pipes controlling. The welding temperature fields, macrostructure, microstructure and mechanical property of the joint were investigated. The result shows that with the heat pipes controlling, the maximum peak temperature decreased by 100 °C. The average duration of high temperature was 36s which shortens 11s compared to that in air. After applying the heat pipes the microstructure in the weld nugget zone were slightly finer than that in air. The average tensile strength of the welding joints was higher than that in air. The highest tensile strength reached 220.4 MPa, more than 90% of the base material strength; The fracture position located between thermal mechanical affected zone and heat affected zone. Under the condition of applying heat pipes, the number of dimple gradually increased and the tensile rupture pattern was ductile-brittle fracture.

Effect of Solution Treatments on the Microstructures and Mechanical Properties of Mg-2Zn-0.8Mn-0.5Ca Alloy

The microstructures, mechanical properties and fracture behaviors of Mg-2Zn-0.8Mn -0.5Ca alloy are studied in different conditions, including as-cast and solution treated conditions, to reveal the effect of solution treatment on the microstructures and mechanical properties. The morphologies of the solution treated alloys show that the Ca2Mg6Zn3 phases disperse uniformly within the α-Mg matrix after heated solution at 415 °C for 48 h. The mechanincal properties are investigated in as-cast and solution treated alloys. For the as-cast alloy, the rupture pattern is intergranular fracture because the Ca2Mg6Zn3 phases mainly distribute at the grain boundaries. After solution treatment, the fracture pattern mainly becomes to transgranular fracture. After solution treatment, the ultimate tensile strength, the yield strength and the elongation are improved by 39.4 %, 32 % and 81.3 %, respectively.