Location and moment tensor inversion of small earthquakes using 3D Green＇s functions in models with rugged topography： application to the Longmenshan fault zone

With dense seismic arrays and advanced imaging methods, regional three-dimensional （3D） Earth models have become more accurate. It is now increasingly feasible and advantageous to use a 3D Earth model to better locate earthquakes and invert their source mechanisms by fitting synthetics to observed waveforms. In this study, we develop an approach to determine both the earthquake location and source mechanism from waveform information. The observed waveforms are filtered in different frequency bands and separated into windows for the individual phases. Instead of picking the arrival times, the traveltime differences are measured by cross-correlation between synthetic waveforms based on the 3D Earth model and observed waveforms. The earthquake location is determined by minimizing the cross-correlation traveltime differences. We then fix the horizontal location of the earthquake and perform a grid search in depth to determine the source mechanism at each point by fitting the synthetic and observed waveforms. This new method is verified by a synthetic test with noise added to the synthetic waveforms and a realistic station distribution. We apply this method to a series of Mw3.4-5.6 earthquakes in the Longmenshan fault （LMSF） zone, a region with rugged topography between the eastern margin of the Tibetan plateau and the western part of the Sichuan basin. The results show that our solutions result in improved waveform fits compared to the source parameters from the catalogs we used and the location can be better constrained than the amplitude-only approach. Furthermore, the source solutions with realistic topography provide a better fit to the observed waveforms than those without the topography, indicating the need to take the topography into account in regions with rugged topography.

A 3D theoretical model for green management:a case study of Chinese enterprises

Companies that not only abide by environmental regulations, but also discover new techniques and adopt newmanagement methods to reduce negative environmental impacts often have positive effects on corporate profitability. Inorder to meet the needs of sustainability of enterprises and protect environment, the concept of green management isdeveloped and regarded as an important direction of management theory of the 21st century. Though there are manytheories and practices about green management in western countries, they are built based on the developed marketeconomy, which are not suitable for Chinese enterprises absolutely. By analyzing the viewpoints and models of theoverseas and domestic experts and scholars, combining characteristic of China’s market economy, this paper points outthe real connotation of enterprise green management - the combination of ecological harmony (harmony between humanand nature) with human harmony (harmony among people), establishes a 3D theoretical model, points out the defects ofenterprise’s green management in China, reanalyzes and redesigned enterprise green management, which paves the wayfor the deeper and broader development of green management.