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In this paper, we collect and process free-field strong motion recordings from 70 earthquakes for 4.2 ≤ M W ≤ 7.9 at 0 < R rup < 300 km between 2008 and 2018 in the active tectonic regions of southwest China, and then establish a dataset containing 1324 average horizontal ground motion (ROTD50) and corresponding metadata such as parameters of the earthquake source, distance, and site. A new ground motion prediction equation (GMPE) for the average horizontal component of peak ground acceleration (PGA), peak ground velocity (PGV), and 5% damped acceleration response spectra at periods ranging from 0.033 to 8.0 s (SA (T = 0.033–8.0 s)) is introduced. This GMPE considers multiple influencing factors such as magnitude and distance saturation effect, geometric attenuation, style-of-faulting, hanging-wall effect, linear/nonlinear site response, and anelastic attenuation. The residual evaluation and median ground motion are presented. The predicted ground motions using the new GMPE are compared with predictions from the GMPE in western China and five NGA-West2 GMPEs, and the observed ground motions of strong earthquakes which occurred in southwest China. The results show that the proposed GMPE can better reflect the influence of the earthquake source characteristic, propagation media, site effect on the ground motion attenuation characteristic in southwest China, and works well versus independent strong motion data of earthquakes in southwest China, and well reflects the general feature of ground motions for the Wenchuan and Lushan earthquakes that is rich at short-period and weak at long-period. The new GMPE shows outstanding performance estimating the horizontal ground motion of the earthquakes in southwest China for M W 4.2–7.9 (related to style-of-faulting) and R rup = 10–200 km, at sites with V S30 = 140–1130 m/s. • A new GMPE considering multiple influencing factors in southwest China is presented. • Our GMPE can reflects the hanging-wall effect of the reverse and normal faulting. • Our GMPE can reflects captures the nonlinear mean effect of soil. • Our GMPE works well versus independent strong motion data in southwest China. [ABSTRACT FROM AUTHOR]

Understanding sub-lethal effects of nanomaterial may be particularly important to determining ecosystem responses as current levels of nanomaterial release are low compared to levels projected for the future. In this work, the sub-lethal effects of water stable, nanocrystalline fullerenes as C 60 (termed nC 60 ) were studied on Scenedesmus obliquus , a globally distributed phytoplankton. Sub-lethal concentration for S. obliquus was firstly determined as 0.09 mg L −1 using the standard 72 h exposure tests (OECD Guideline 201). Subsequent sub-lethal experiment of nC 60 on the S. obliquus was carried out for 60 d and focused on the photosynthesis processes. The results demonstrate that upon sub-lethal exposure, the photosynthetic products of polysaccharide, soluble protein and total lipid were decreased with exposure time. The photosynthetic pigments of chlorophyll a and chlorophyll b were negatively impacted. Further investigations indicate that the decrements in photosynthetic products and pigments were mainly due to the algal Mg 2+ decrement (by 40%) at the sub-lethal concentration (0.09 mg L −1 ) of nC 60 . The decrement in Mg 2+ of S. obliquus was due to the inhibition of Mg 2+ -ATPase activity caused by nC 60 . Sum up, these results not only describe the sub-lethal effects but also provide the probably mechanism for sub-lethal effects of nC 60 on exposed S. obliquus . [ABSTRACT FROM AUTHOR]

Scenarios of earthquakes play an important role in planning and coordinating emergency response, seismic risk management, and identifying exposure of structures, lifelines, and utilities. We describe the calculation of distributions of ground shaking that might be generated if the 1568 Shaanxi Gaoling M~7 earthquake were to recur. In order to adjust the Ground Motion Prediction Equations (GMPEs) for the local conditions, we use the ShakeMap software to calculate a scenario of the nearby 1556 Huaxian M8¼ earthquake, for which the distribution of isoseismals is constrained by historical records. We use the ASK13 GMPEs, and find that, by augmenting the resulting ground shaking by 50% of its standard deviation, we can satisfactorily reproduce the historical observations. This scheme is then applied to the calculation of a scenario ShakeMap for the 1568 Shaanxi Gaoling M6¾ earthquake. The rupture parameters of the seismogenic faults for each of these scenarios are determined from field observations. The macroscopic seismic site conditions for this area are calculated from the topographic gradient V s 30 model of Wald and Allen [1]. The resultant scenario ShakeMap provides the basis for the calculations of seismic hazard and risk for Weinan city and its surroundings, which are described elsewhere in this issue. [ABSTRACT FROM AUTHOR]

[Display omitted] • The new ground motion prediction model can capture the nonlinear mean effect of soils in the capital circle region of China. • Our ground motion prediction model can predict the observed ground motions in this region. • The regional variability of ground motion is caused by the difference in anelastic attenuation and site response. • The regional differences in the anelastic attenuation at rock sites decrease with increasing periods. • GMPMs developed using data from different magnitude ranges within the same region should not be used interchangeably. Based on strong motion and seismic velocity records from small-to-moderate earthquakes in the capital circle region of China, we developed a new ground motion prediction model (GMPM) that incorporates magnitude, geometric attenuation, anelastic attenuation, and linear/nonlinear site response terms. The GMPM was subjected to evaluation through residual analysis. We compared the median predictions of the GMPM with those of two commonly used local GMPMs, as well as the observed ground motions in this region. Furthermore, we conducted an investigation into the differences between the GMPM and four NGA-West2 models. Additionally, we explored certain model parameters that could potentially explain these differences. The results indicate that the GMPM effectively captures the magnitude-dependent attenuation and nonlinear average effect of soil sites. The GMPM demonstrates the capability to predict horizontal peak ground acceleration (PGA), peak ground velocity (PGV), and spectral acceleration (SA (T = 0.01–3.0 s)). The model is applicable for surface wave magnitudes (M S = 3.1–5.1), hypocentral distances (R hyp = 10–200 km), and V S30 = 103–1070 m/s in the capital circle region of China. There are significant differences in anelastic attenuation at rock sites between southern California and the capital circle region of China. These differences decrease with increasing periods and largely diminish in far sources and soil sites. This is primarily because the effect of anelastic attenuation is neutralized by the greater site amplification of ground motion in southern California, especially over medium and long periods. The difference in ground motion observed in small-to-moderate earthquakes across different regions is predominantly influenced by long-distance attenuation and dissimilarities in site responses. [ABSTRACT FROM AUTHOR]

Lateral variations of shear wave velocity (V S) profile and time-averaged shear wave velocity in the upper 30 m (V S 30) are important indicators of site condition and significant contributors to uncertainty in earthquake ground motion and seismic hazards. Few previous studies involved in quantifying these lateral variations, especially at short distances, due to limited data at closely spaced sites. This study quantitatively investigated the lateral variation of V S profile and V S 30 over plain and piedmont terrains, focusing on short distances ranging from hundreds of meters to several kilometers. 2510 plain and 749 piedmont borehole profiles from the mainland China borehole profile database were employed to examine these variations using the variogram as the geo-statistics tool. The main findings include: 1) Over plain terrain, the variation in site conditions between sites does not significantly increase with separation distance within a certain range (typically from 1 km to 3–5 km). Over piedmont terrain, site condition variation steadily increases with distance. 2) The variation of site condition over piedmont terrain is higher than that over plain terrain. Nonetheless, for both terrains, the dispersion of site condition between sites at distance of <1 km is engineering negligible, and the correlation of site conditions between sites within 5 km remains strong; 3) For both terrains, the lateral variation of V S in deeper layers is higher than that in shallower layers. The study outcomes emphasize the importance of incorporating the information of nearby measurements in site condition estimations. The study outcomes can also be utilized in the optimization of borehole sampling design for microzonation projects and the evaluation of site condition dispersion at inferred sites. • Lateral variations of V S profile & V S 30 over plain & piedmont terrains were modeled. • The study focuses on lateral variations at short distance, down to < 1 km scale. • For gentle terrains, site conditions within short distance are strong correlated. • Plain has lower site condition variation than piedmont, with distinct properties. [ABSTRACT FROM AUTHOR]