Seismic Tomography and Earthquake Relocation in North China Craton From 2008 to 2017

We present a newly developed three-dimensional seismic velocity model and high-precision earthquake relocations in North China using seismic data recorded by the National Earthquake Data Center of China from 2008 to 2017 through the double-difference tomography (tomoDD) method. The Vp model in the upper crust (below 15 km) generally agrees with those in previous studies, and it fits well with the geological structure. The result shows that the vast majority of earthquakes in North China occurred at the junction of the low-velocity zone (depression zone) and the high-velocity zone (uplift zone). This situation is difficult to change in the short term, so it is highly unlikely that another earthquake of the magnitude of 7.2 in Xingtai in 1966 and 6.2 in Zhangjiakou North in 1998 will occur in these areas in the near future. But in the Tangshan earthquake area, the situation is completely different. Our joint inversion results of 3D P-wave velocity structure and earthquake relocation show that there is a narrow low-velocity anomaly perpendicular to the surface at 20–25 km in the Tangshan area and there are no earthquakes in this anomaly area. The formation of this low-velocity zone is most likely due to the remnants of the delayed subduction of the Pacific plate to the Eurasian plate, and in the context of the Kobe earthquake in Japan, we believe that this anomaly will continue to erode the Tangshan subsurface structure and may cause strong earthquakes in the future. Our study provides the groundwork for future earthquake prevention and mitigation in North China

Study on Plant Growth and Nutrient Uptake under Different Aeration Intensity in Hydroponics with the Application of Particle Image Velocimetry

Aeration is considered beneficial for hydroponics. However, little information is available on the effects of aeration, and even less on solutions that use bubble flow and their agronomic effects. In this study, the effects of aeration intensity on plants were studied through cultivation experiments and flow field visualization. It was found that the growth of plants did not increase linearly with an increase in aeration intensity. From the results of this study, when the aeration intensity was within the low range (0.07–0.15 L·L−1 NS·min−1), increasing the aeration intensity increased the plant growth. However, after the aeration intensity reached a certain extent (0.15–1.18 L·L−1 NS·min−1), some indicators did not change significantly. When the aeration intensity continued to increase (1.18–2.35 L·L−1 NS·min−1), growth began to decrease. These results show that for increasing dissolved oxygen and promoting plant growth, the rule is not “the higher the aeration intensity, the better”. There is a reasonable range of aeration intensity within which crops grow normally and rapidly. In addition, increasing the aeration intensity means increasing energy utilization and operating costs. In actual hydroponics production, it is very important to find a reasonable aeration intensity range

低酸素トレーニングが炎症およびメタボリック危険因子に及ぼす影響 ‐健常者を対象としたクロスオーバー研究‐

博士(医学)岐阜大学(Gifu University

Seismic velocity structure and characteristics of induced seismicity at the Geysers Geothermal Field, eastern California

We present a newly developed three-dimensional seismic velocity model, high-precision earthquake relocations and focal mechanisms near the Geysers Geothermal Field in eastern California using seismic data recorded by the Northern California Earthquake Data Center from 1984 to 2015. The velocity model generally agrees with those in previous studies with the Vp model mainly corresponding to rock composition and the Vp/Vs model more correlated with fluid content. The dominating low Vp/Vs anomalies observed from 0 to 4km depth below sea level is a reflection of the geothermal reservoir. The waveform cross-correlation relocated seismicity shows both spatial and temporal correlations with the geothermal operations in the study area, indicating that they are induced seismicity. Although the focal solutions are dominated by normal and strike-slip regimes throughout our entire study time period, there has been an increase in reverse faulting since 2008, which may be caused by the thermal contraction associated with the Northwest Geysers Enhanced Geothermal System project between 2008 and 2012. Our study provides a groundwork for future seismological studies in The Geysers

Seismic velocity structure and characteristics of induced seismicity at The Geysers geothermal field, eastern California

We present a newly developed three-dimensional seismic velocity model, high-precision earthquake relocations and focal mechanisms near the Geysers Geothermal Field in eastern California using seismic data recorded by the Northern California Earthquake Data Center from 1984 to 2015. The velocity model generally agrees with those in previous studies with the Vp model mainly corresponding to rock composition and the Vp/Vs model more correlated with fluid content. The dominating low Vp/Vs anomalies observed from 0 to 4 km depth below sea level is a reflection of the geothermal reservoir. The waveform cross-correlation relocated seismicity shows both spatial and temporal correlations with the geothermal operations in the study area, indicating that they are induced seismicity. Although the focal solutions are dominated by normal and strike-slip regimes throughout our entire study time period, there has been an increase in reverse faulting since 2008, which may be caused by the thermal contraction associated with the Northwest Geysers Enhanced Geothermal System project between 2008 and 2012. Our study provides a groundwork for future seismological studies in The Geysers

Techno-Economic Feasibility Analysis of a Stand-Alone Photovoltaic System for Combined Aquaponics on Drylands

An open-field cultivation combined-type aquaponic system (OCAS) was developed to effectively utilize saline groundwater and prevent soil salinization while ensuring food production in drylands. To achieve the sustainable food production of the OCAS in power-scarce areas, a stand-alone photovoltaic system (PVS) for the OCAS was designed through a feasibility study of utilizing solar energy to meet its power demand. As a case study, the OCAS was established in La Paz, Baja California Sur, Mexico, with power consumption 22.72 kWh/day and annual average daily global horizontal irradiation (GHI) 6.12 kWh/m2/day, considering the 2017 meteorological data. HOMER software was employed for performance analysis and techno-economic evaluation of an appropriate PVS. Thousands PVS configurations were evaluated in terms of total net present cost (NPC) and levelized cost of energy (COE). The PVS that fulfilled the power demand and had the smallest NPC was proposed, for which the NPC and COE were calculated as $46,993 and$0.438/kWh, respectively. The relationship between its annual power supply and power demand of the OCAS was also analyzed in detail. It was found that the operation hours and the amount of power generation by the proposed PVS were 4156 h and 19,106 kWh in one year. Additionally, it was predicted that the excess power would occur almost every afternoon and reach 43% of the generated power. Therefore, the COE can be further reduced by rationally utilizing the excess power during operation