Anomaly detection on displacement rates and deformation pattern features using tree-based algorithm in Japan and Indonesia

Research on strain anomalies and large earthquakes based on temporal and spatial crustal activities has been rapidly growing due to data availability, especially in Japan and Indonesia. However, many research works used local-scale case studies that focused on a specific earthquake characteristic using knowledgedriven techniques, such as crustal deformation analysis. In this study, a data-driven-based analysis is used to detect anomalies using displacement rates and deformation pattern features extracted from daily global navigation satellite system(GNSS) data using a machine learning algorithm. The GNSS data with188 and 1181 continuously operating reference stations from Indonesia and Japan, respectively, are used to identify the anomaly of recent major earthquakes in the last two decades. Feature displacement rates and deformation patterns are processed in several window times with 2560 experiment scenarios to produce the best detection using tree-based algorithms. Tree-based algorithms with a single estimator(decision tree), ensemble bagging(bagging, random forest and Extra Trees), and ensemble boosting(AdaBoost, gradient boosting, LGBM, and XGB) are applied in the study. The experiment test using realtime scenario GNSSdailydatareveals high F1-scores and accuracy for anomaly detection using slope windowing 365 and 730 days of 91-day displacement rates and then 7-day deformation pattern features in tree-based algorithms. The results show the potential for medium-term anomaly detection using GNSS data without the need for multiple vulnerability assessments.

Deformation patterns and hydrocarbon potential related to intracratonic strike-slip fault systems in the east of Central Uplift Belt in the Tarim Basin

Strike-slip faults,proven to be closely linked to hydrocarbon migration and accumulation,are wide-spread in the Tarim Basin Craton.Deformation patterns in the eastern part of the Central Uplift Belt of the Tarim Basin are analyzed in detail to understand the deformation model and genetic mechanism of strike-slip faults,how their patterns impact reservoir formation and influence oil and gas potential.Regional tectonic events are taken into consideration to identify the primary factors that controlled the development of strike-slip faults in the region.The Tazhong Uplift in the eastern part of Central Uplift Belt is believed to be a complex anticlinal uplift formed by compression-and-torsion acting on the Cambrian-Middle Ordovician platform during the middle-late Caledonian period.Multi-stage development of this north-trending fault-fold belt and the NE-trending strike-slip faults make it structurally complex.The NE-trending Paleozoic strike-slip faults were formed jointly by the differential thrusting of the Tazhong Uplift along Fault No.Ⅰand the NE-trending shear sliding of the basal fault blocks during the middle-late Caledonian-early Hercynian.Based on the distribution of effective source rocks,the tectonic setting during the period critical to hydrocarbon accumulation,and the distribution of conductive faults,the northern slope of the Tazhong Upliftd-especially its west-central part where the NE-trending faults are developed is not only located close to the northern hydrocarbon source rock area but also possesses conditions suitable for the development of carbonate reservoirs.In addition,the NE-trending faults provide passage for initial development of the reservoir and the subsequent migration of oil and gas from the Aman area to the uplifted zone,making the Tazhong Uplift an extremely favorable area for oil and gas accumulation with substantial potential for exploration.

Dynamic pattern characteristics of fault deformation and gravity field in the development process of Yongdeng M_S=5.8 earthquake

In this paper, the fault deformation abnormality, dynamic evolution features of gravity and vertical deformation field in the seismogenic process of the Yongdeng, Gansu Province earthquake on July 22, 1995 are studied primarily. There appeared α β γ tri stage anomaly at three sites near the epicenter, and there appeared anomalies of step and sudden jump at more than 10 sites in outer region since 1993. The high value area before shock, coseismic effect and process of recovery aftershock were monitored by portable gravity data. Data reflects the changing process of fault movement from the quasi linear to the nonlinear in the near source region during seismogenic development of the Yongdeng earthquake and evolution of gravity field from heterogeneity of seismogenic term to quasi homogeneity of postseismic term. There exists close relationship between strong earthquake and dynamic evolution of regional stress strain field. Considering all above, the experience and lessons in this medium short term prediction test are summarized.

Effect of Vibrational Modes on Sand Pressure and Pattern Deformation in the EPC Process

During the EPC (expendable pattern casting) process, one of the essential requirements is to prevent pattern distortion duringsand filling and compaction. A new method which vibrates the system in a two-dimensional circular mode has been appliedto the EPC process. The molding properties of unbonded sand obtained by this new vibration mode are investigated andcompared with those in the one-dimensional vertical mode. For adequate compaction of sand. the circular vibration mode ismore effective than the vertical mode. Sand became more fluidized by the circular vibration and the particle pressure coefficientwas close to unity The particle pressure coefficient, which is defined as the ratio of horizontal to vertical sand pressure, isresponsible for the effectiveness of sand filling.

Research on dynamics patterns and parameter characters of crustal deformation field before and after strong earthquake

Based on the dynamic monitoring data of crustal deformation, the parameter evolution for the dynamics pattern and fractal dimension of crustal deformation field and the integral activity level of many faults etc. before and after the Tangshan (1976) and Lijiang (1996) strong earthquakes and others are studied by using the method of pattern dynamics. It is exposed that two time space characters, the ordered dimension drop of the deformation field and the accelerated motion of multi fault before an earthquake, are probably caused by the deformation localization and fault softening after the seismogenic process enters the nonlinear stage. They could be an important seismic precursor if they occurred repeatedly before strong earthquakes.

The Ductile Deformation Characteristics of Caledonian Intracontinental Orogeny in the Northeastern Jiangshan-Shaoxing Tectonic Zone:Insights from Magnetic Fabric Study and Its Geodynamic Implication

The Jiangshan-Shaoxing tectonic zone was the northeastern boundary between the Yangtze Block and the Cathaysia Block during the Neoproterozoic and was an intracontinental orogenic belt during late of the early Paleozoic. In this tectonic zone, there develops a lot of mylonite underwent strong ductile deformation and schist, gneiss, and amphibolite with medium and high grade metamorphism which was formed during the late of early Paleozoic. The research of geometry and kinematic of ductile deformation in Jiangshan-Shaoxing tectonic zone is very important to reveal the tectonic process of intracontinental orogeny. This paper uses the anisotropy of magnetic susceptibility （AMS） to determine the ductile deformation geometry and kinematic of Jiangshan-Shaoxing tectonic zone combing with the field survey. In this study, 190 specimens of 19 locations and 221 specimens of 23 locations from Wangjiazhai section and Lipu-Sizhai section were analyzed. The magnetic foliation over magnetic lineation in both Wangjiazhai and Lipu-Sizhai sections together with the field observations indicated a compressional deformation pattern. 3 and 4 strong ductile deformation zones can be established in the Wangjiazhai section and the Lipu-Sizhai section, respectively. According to the magnetic fabric and petro-fabric studies, the Northeastern Jiangshan-Shaoxing tectonic zone suffered two kinds of deformation patterns during the late early Paleozoic, i.e., the thrusting deformation followed by sinistral shear deformation.

Simultaneous 2D in-plane deformation measurement using electronic speckle pattern interferometry with double phase modulations

Electronic speckle pattern interferometry（ESPI） and digital speckle pattern interferometry are wellestablished non-contact measurement methods. They have been widely used to carry out precise deformation mapping. However, the simultaneous two-dimensional（2D） or three-dimensional（3D） deformation measurements using ESPI with phase shifting usually involve complicated and slow equipment. In this Letter, we solve these issues by proposing a modified ESPI system based on double phase modulations with only one laser and one camera. In-plane normal and shear strains are obtained with good quality. This system can also be developed to measure 3D deformation, and it has the potential to carry out faster measurements with a highspeed camera.

Measurement of out-of-plane deformation of curved objects with digital speckle pattern interferometry

Digital speckle pattern interferometry （DSPI） is a high-precision deformation t technique for planar objects. However, for curved objects, the three-dimensional （3D） shape information is needed in order to obtain correct deformation measurement in DSPI. Thus, combined shape and deformation measurement techniques of DSPI have been proposed. However, the current techniques are either complex in setup or complicated in operation. Furthermore, the operations of some techniques are too slow for real-time measurement. In this work, we propose a DSPI technique for both 3D shape and out-of-plane deformation measurement. Compared with current techniques, the proposed technique is simple in both setup and operation and is capable of fast deformation measurement. Theoretical analysis and experiments are performed. For a cylinder surface with an arch height of 9 mm, the error of out-of-plane deformation measurement is less than 0.15 μm. The effectiveness of the proposed scheme is verified.