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On September 16, 2021, a MS6.0 earthquake struck Luxian County, one of the shale gas blocks in the Southeastern Sichuan Basin, China. To understand the seismogenic environment and its mechanism, we inverted a fine three-dimensional S-wave velocity model from ambient noise tomography using data from a newly deployed dense seismic array around the epicenter, by extracting and jointly inverting the Rayleigh phase and group velocities in the period of 1.6-7.2 s. The results showed that the velocity model varied significantly beneath different geological units. The Yujiasi syncline is characterized by low velocity at depths of ~ 3.0-4.0 km, corresponding to the stable sedimentary layer in the Sichuan Basin. The eastern and western branches of the Huayingshan fault belt generally exhibit high velocities in the NE-SW direction, with a few local low-velocity zones. The Luxian MS6.0 earthquake epicenter is located at the boundary between the high- and low-velocity zones, and the earthquake sequences expand eastward from the epicenter at depths of 3.0-5.0 km. Integrated with the velocity variations around the epicenter, distribution of aftershock sequences, and focal mechanism solution, it is speculated that the seismogenic mechanism of the main shock might be interpreted as the reactivation of pre-existing faults by hydraulic fracturing. [ABSTRACT FROM AUTHOR]

On 12 May 2008, the MW 7.9 Wenchuan earthquake triggered widespread damaging landslides in many parts of the Longmen Shan area. Among these landslides, the Donghekou ejection landslide is quite special. It is located at the northeast end of the Beichuan rupture, and it has caused a great loss of life at the villages of Donghekou, Qinchuan, and Sichuan Provinces. Because of its special location, this ejection landslide differs from landslides caused by gravity or rainstorms only; the sliding surface is not uniformly continuous. Instead, two sections can be distinguished: an upper section with a step sliding surface and a lower section more gently dipping. The landslide started with material ejection caused by large local seismic acceleration, throwing rocks into the air with a parabolic trajectory before they fell back to the ground. In this paper, we analyze geologic and geomorphologic conditions that favored the occurrence of this landslide, and we introduce a simple tectonicgeomorphology model to explain the mechanism that led to the ejection landslide. We find that the location of the landslide zone, along with the domino-like ground tension cracks observed on both sides of the Beichuan rupture, is controlled by the propagation of the rupture. Our result also suggests that, in addition to local seismic shaking intensity, horizontal acceleration, and geomorphologic and geologic conditions, the vertical acceleration and the style of faulting could also play an important role in the occurrence of earthquake-triggered landslides. [ABSTRACT FROM AUTHOR]

For the gas reservoir of the fourth Member of Dengying Formation in Moxi area, Sichuan Basin, the reservoir space is various, the reservoir heterogeneity is strong and the fluid seepage law is complex. The development process of gas reservoir shows the following characteristics. (1)The gas well has a large difference in productivity, mainly in medium and high production wells. (2)There are great differences in stable production capacity of gas wells, and most of them have strong stable production capacity. (3)Staged acid fracturing technology and special technology wells can greatly improve gas well productivity. In order to find out the distribution characteristics of gas well productivity, gas reservoir engineering research and comprehensive geological research are combined to analyze the distribution characteristics of gas well productivity in the plane. The research shows that the gas well productivity characteristics have obvious subdivision of areas and belts characteristics in the plane. The gas well productivity is mainly distributed in four areas in the plane. The first area is that the thickness of overlying limestone is 0 m. The second area is that the thickness is 0-5 m. The third area is that the thickness is 5-20 m. The fourth area is that the thickness is more than 20 m. At the same time, the fitting formula of gas well productivity and overlying limestone thickness in different regions has been established. On the other hand, gas well productivity is mainly distributed in three belts which include platform edge, platform interior and slop belt. The gas well productivity decreases from platform edge, platform interior to slop belt. The research results can effectively support development area selection, well location optimization in the process of gas reservoir development evaluation and gas well productivity evaluation. [ABSTRACT FROM AUTHOR]

Background: Acute renal injury (AKI) is a common complication of lung transplantation. However, there has been no related research on whether the relationship between fluid balance and input and output influences the occurrence of early AKI. This study aimed to explore the relationship between early fluid balance and input and output on the incidence of early AKI after lung transplantation. Methods: Data from 31 patients who underwent lung transplantation in the Department of Intensive Care Medicine of the Sichuan Academy of Medical Sciences, Sichuan People's Hospital, from August 2018 to July 2021 were collected. To summarize the occurrence of early AKI after lung transplantation, The main indicators of lung transplantation patients were collected. The risk factors for early AKI after lung transplantation were analyzed. Results: Among the 31 patients who underwent lung transplantation, 21 had early postoperative AKI, with an incidence rate of 67.7%. Compared with the non-AKI group, the hospitalization and ICU hospitalization times of the AKI group were longer (P < 0.05). Multivariate regression analysis showed that intraoperative input volume, BMI, and fluid balance on the first day after lung transplantation were independent risk factors for AKI. Conclusion: Intraoperative input volume, BMI, and fluid balance on the first day after lung transplantation were independent risk factors for AKI. [ABSTRACT FROM AUTHOR]