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A rapid and accurate estimate of earthquake damage is a key component in a successful earthquake early warning (EEW) system. The cumulative absolute velocity (CAV) is an important and widely used parameter to measure ground motion intensity, but it cannot be correctly estimated via the traditional approach with the limited information available in typical EEW systems. Therefore, current EEW systems cannot effectively use CAV to predict earthquake damage. Herein, a CAV prediction model (DLcav) based on convolutional neural networks was proposed for EEW systems. DLcav is an end‐to‐end solution to continuously predict CAV using arriving seismic waves of increasing length and supplemented with additional auxiliary information. The effectiveness of DLcav to predict CAV was tested based on Japanese ground motion records, and the generalization ability of DLcav was assessed using the ground motion records from Chile. The results demonstrate that DLcav can rapidly predict CAV with good accuracy, which will help better estimate earthquake damage in EEW systems. [ABSTRACT FROM AUTHOR]

Abstract: Field investigations following the 2008 Wenchuan earthquake (M s =8.0) identified 118 liquefaction sites nearly all of which are underlain by gravelly sediment in the Chengdu Plain and adjacent Mianyang area. Field studies, including core drilling, dynamic penetration tests (DPT), and multiple channel analysis of surface wave velocity tests (MASW) for measurement of shear wave velocities, reveal the following: (1) Sand boils and ground fissures, indicative of liquefaction, occurred across hundreds of square kilometers affecting 120 villages, 8 schools and 5 factories. (2) The Chengdu plain is underlain by sandy gravels ranging in thickness up to 540m; loose upper layers within the gravels beds liquefied. (3) Mean grain sizes for gravelly layers that liquefied range from 1mm to more than 30mm. (4) Shear wave velocities in gravels that liquefied range up to 250m/s. (5) A 50% probability curve, developed from logistic procedures, correctly bounds all but four data points for the 47 compiled V s data. [Copyright &y& Elsevier]

In this paper, a distribution map of gravelly soil liquefaction that was caused by the Wenchuan Ms 8.0 earthquake in China is proposed based on a detailed field investigation and an analysis of geological soil profiles. The geological background of the earthquake disaster region is summarized by compiling geological cross sections and borehole logs. Meanwhile, four typical liquefied sites were selected to conduct sample drillings, dynamic penetration tests (DPT), and shear wave velocity tests, to understand the features of liquefied gravelly soil. One hundred and eighteen (118) liquefied sites were investigated shortly after the earthquake. The field investigation showed: (1) sandboils and waterspouts occurred extensively, involving thousands of miles of farmland, 120 villages, eight schools and five factories, which caused damage to some rural houses, schools, manufacturing facilities and wells, etc.; (2) the Chengdu plain is covered by a gravelly soil layer with a thickness of 0 m to 541 m according to the geological cross sections; (3) there were 80 gravelly soil liquefied sites in the Chengdu plain, shaped as five belt areas that varied from 20 km to 40 km in length, and about ten gravelly soil liquefied sites distributed within Mianyang area; and (4) the grain sizes of the sampled soil were relative larger than the ejected soil on the ground, thus the type of liquefied soil cannot be determined by the ejected soil. The gravelly soil liquefied sites are helpful in enriching the global database of gravelly soil liquefaction and developing a corresponding evaluation method in further research efforts. [ABSTRACT FROM AUTHOR]

The diamond mosaic grown on the single-crystal diamond substrates by the microwave plasma chemical vapor deposition (MPCVD) method has been studied. The average growth rate was about 16–17 μm/h during 48 hours' growth. The surface morphologies of the as-grown diamond layer were observed. It was found that the step flow was able to move across the substrates and cover the junction interface. Raman spectroscopic mapping in the central area of the junction revealed the high stress region movement across the junction interface from one substrate to the other for about 200–400 μm. High-resolution X-ray diffractometry (HRXRD) results proved that the surface step flow movement direction had nothing to do with the off-axis directions of the original substrates. It was found that the surface height difference of substrate was the main driving force for the step flow movement, junction combination and surface morphology changing. The mechanism of the mosaic interface junction combination and step flow transformation on the mosaic surface was proposed. [ABSTRACT FROM AUTHOR]

The high-quality single crystal diamond (SCD) grown in the Microwave Plasma Chemical Vapor Deposition (MPCVD) system was studied. The CVD deposition reaction occurred in a 300 torr high pressure environment on a (100) plane High Pressure High Temperature (HPHT) diamond type II a substrate. The relationships among the chamber pressure, substrate surface temperature, and system microwave power were investigated. The surface morphology evolution with a series of different concentrations of the gas mixture was observed. It was found that a single lateral crystal growth occurred on the substrate edge and a systemic step flow rotation from the [100] to the [110] orientation was exhibited on the surface. The Raman spectroscopy and High Resolution X-Ray Diffractometry (HRXRD) prove that the homoepitaxy part from the original HPHT substrate shows a higher quality than the lateral growth region. A crystal lattice visual structural analysis was applied to describe the step flow rotation that originated from the temperature driven concentration difference of the C2H2 ion charged particles on the SCD center and edge. [ABSTRACT FROM AUTHOR]