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1.
On the basis of the assumption that ω^2 model accords with source displacement spectra, we have obtained the mathematical expressions for calculating apparent stresses of moderate-small shocks from low-frequency flat level and comer frequency. By using digital seismic records, apparent stress values are calculated for 823 moderate-small shocks of 4 earthquake series in Yunnan area following corrections for instrument response, propagation influence and site effect. The results show that for the 4 earthquake series in Yunnan area, apparent stress hints precursory information, which means that if a moderate-small shock occurs with apparent stress larger than 1 MPa in an earthquake series, a moderate-strong earthquake will occur afterwards; and if there is not moderate-small shock with apparent stress larger than 1 MPa after a moderate-strong event in an earthquake series, strong aftershock will not occur. The research also indicates that the average apparent stress value is 0.8 MPa in Yunnan area, therefore, apparent stress is not obviously related to seismic magnitude. 相似文献
2.
Feng Chen Da-Yuan Chen Qi-Ping Cao Shu-Jun Yu Dong-Jun Xu Cong-Xin Chen Yu-Liang Yu Jian-Hao Sheng 《地震学报(英文版)》1993,6(3):721-729
In the strip limestone mine in Guiding county, Guizhou Province the shear and frictionin situ tests of rock body were made for the three typical inclined weak bands C
3
1
/C
3
1
, C
3
1
/C
2
2
and C
2
2
/C
2
1
. The tests were made according to the second scheme of cuneate sample of the standards on rock mechanics test of Water Conservancy
and Electricity Ministry. The changes of the resistivity in the weak band and the acoustic speed across the weak band were
measured in the same time. The apparent resistivity data, obtained for 8 samples on 27 measure lines in 38 cycle tests, show
that the apparent resistivity changes have rather obvious characters as follows: 1. At shear and friction stage, the change
of the apparent resistivity accelerates after the yield point, and reaches the maximum of change rate and change amplitude
near fracture point (except the lines with resistivity invariant); 2. On the same sample, the resistivity changes are different
on the various lines and related to the location settled the lines, there are some “sensitive” location; 3. At the stage of
preloading normal stress before shearing, the resistivity decreases on most lines, but on a few lines the resistivity does
not changes; 4. After unloading shear stress, the resistivity could not recover completely and the hysteresis of resistiviity
takes place on a few lines.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 217–223, 1993.
Support for this research was received from Guiding strip limestone mine, Guizhou Organic Chemistry Factory.
This research is supported by the Chinese Joint Seismological Science Foundation. 相似文献
3.
以植物组织培养技术培养的水花生愈伤组织为实验材料,研究了过量Zn2+(0、0.2、0.4、0.8、1.6 mmol/L)对水花生愈伤组织的氧化损伤及多胺代谢的影响.结果表明,随着Zn2+浓度增加:(1)水花生愈伤组织的超氧阴离子产生速率和硫代巴比妥酸反应物水平显著提升,超氧化物歧化酶活性明显抑制,叶绿素a含量显著降低;(2)精氨酸脱羧酶和鸟氨酸脱羧酶活性均升高,多胺氧化酶和二胺氧化酶活性在低Zn2+浓度处升高、高Zn2+浓度处降低;(3)总腐胺和总精胺含量在低Zn2+浓度处降低、高Zn2+浓度处增加,总亚精胺含量仅在Zn2+浓度为1.6 mmol/L时有显著增加;(4)游离态腐胺含量变化与总腐胺含量相似,游离态亚精胺含量在高Zn2+浓度时下降,游离态精胺含量仅在Zn2+浓度为0.2 mmol/L时略有下降;(5)结合态腐胺和精胺在Zn2+浓度为0.2 mmol/L时下降而在其余处理组中上升,结合态亚精胺含量各处理组中均增加;(6)束缚态腐胺和亚精胺含量均下降.可见,过量Zn2+胁迫导致水花生愈伤组织氧化性损伤,并扰乱其多胺代谢平衡;束缚态多胺向结合态多胺的转化是过量Zn2+胁迫下水花生愈伤组织多胺代谢变化的一个显著特征;以结合态为代表的内源性多胺积累对水花生愈伤组织抵抗过量Zn2+胁迫具有重要意义. 相似文献
4.
5.
Sébastien Nomade Giovanni Muttoni Hervé Guillou Eric Robin Giancarlo Scardia 《Quaternary Geochronology》2011,6(5):453-457
The Ceprano calvarium, found in 1994 in Italy and attributed to Homo cepranensis, is one of the most celebrated hominin remains of Europe. It was considered at least 700 ka-old until a recent investigation incorporating magnetostratigraphy and K-Ar ages from the literature assigned to the calvarium an age of ∼450 (+50, −100) ka. Here we pin down the age of the Ceprano calvarium to 353 ± 4 ka (±1σ external) by means of new 40Ar/39Ar dating on K-feldspars retrieved from the sediments that hosted the skull. In absence of evidence of reworking, this refined age sinks the conviction that H. cepranensis belonged to human evolution at the Brunhes–Matuyama boundary (c.a. 781 ka). Our refined age indicates that H. cepranensis lived in central Italy probably during the cold period of marine isotope stage (MIS) 10, and that despite his archaic morphology and lack of Neanderthal traits, he was contemporaneous with more advanced species such as H. heidelbergensis. 相似文献
6.
Jianlin Zhu Guangming Zeng 《Stochastic Environmental Research and Risk Assessment (SERRA)》2006,21(2):143-149
Detrended fluctuation analysis (DFA) and power spectrum density are applied to verify the presence of temporal scaling behavior and long-range persistence (LRP) of weekly hydrogen ion deposition (WHD), NO3- and SO42- deposition series in National Atmospheric Deposition Program, USA, for the period 1978–2001. The results show a common scaling behavior for all sites analyzed. Two distinct scaling regions are identified by DFA1, one corresponding to 1 month to 1 year and the other to 1 year to 5 years. The WHD series obey power-law in two temporal regimes respectively with mean DFA1 scaling exponents α
1≈0.68 and α
2≈0.45, implying the presence of LRP in the acid deposition series and there is a tendency for a large deposition event to be followed by another large event, and vice versa. For DFA2–DFA4, however, the annual crossover, which divides the temporal scale into two regimes, disappears gradually with the order q of DFAq increasing, and the two scaling regimes turn to share the same scaling exponent close to α
1. The result indicates that the scaling behavior exits in the two regimes with the same scaling exponent α
1, and LRP prevails during the examined 1-month to 5-years scale. NO3- and SO42- deposition evolve the same way as WHD does, implying the pollutants involving in acid deposition may share some prominent mechanism controlling their evolutions. We ascribe the long-range power-law scaling of acid deposition evolutions to the self-organized critical behavior of atmosphere under pollution stress and it should be considered in the trend prediction of acid deposition as an important factor. 相似文献
7.
Keiiti Aki 《Pure and Applied Geophysics》1995,145(3-4):647-676
In order to develop capabilities for predicting earthquake processes on the basis of known fault zone structures and stress conditions, we need to find relations between seismogenic structures and processes. In the present paper we search for the scale dependence in various earthquake phenomena with the hope to find some structures in the earth that may control the earthquake processes. Among these phenomena, we shall focus on (1) geologic structures which play some role in nucleation and stopping of earthquake fault rupture, (2) depth ranges of the brittle seismogenic zone, (3) asperities and barriers distributed over a fault plane, (4) source-controlledf
max effect, (5) nonfractal behavior of creep events, and (6) temporal correlation between codaQ
–1 and seismicity of earthquakes with magnitude characteristic to a given area. Our review of various scale-dependent phenomena leads us to propose a working hypothesis that the temporal change in codaQ
–1 may reflect the activity of creep fractures near the brittle-ductile transition zone. 相似文献
8.
ChangLiang Yin TanDong Yao LiDe Tian DongNian Liu WuSheng Yu DongMei Qu 《中国科学D辑(英文版)》2008,51(7):966-975
Oxygen stable isotope of atmospheric water vapor is widely used to study the modern process of climate. Atmospheric water
vapor samples were collected at Dlingha, northeast of Tibetan Plateau during the period from July 2005 to February 2006. The
variation of δ
18O and the relationships between δ
18O and both the temperature and specific humidity are analyzed in this paper. Results show that the seasonal variation of δ
18O of atmospheric water vapor at Delingha is remarkable with higher δ
18O in summer and lower δ
18O in winter. The temporal variation of vapor δ
18O shows obvious fluctuations, with magnitude of over 37‰ The daily variation of the δ
18O is highly correlated with air temperature. The relationship between δ
18O and atmospheric water vapor content is complex. Study shows that δ
18O of atmospheric water vapor is positively correlated with specific humidity in winter in seasonal scale and inversely correlated
with specific humidity in summer rainy period. The δ
18O values of atmospheric water vapor are lower than those of precipitation at Delingha, and the average difference is 10.7‰
Variations of δ
18O of atmospheric water vapor is also found to be affected by precipitation events, The model results show that the precipitation
effect could have caused the vapor δ
18O in the raining season to lower by 7% in average in July and August.
Supported by the National Natural Science Foundation of China (Grant Nos. 40671043, 40571039 and 40771048) and National Basic
Research Program of China (Grant No. 2005CB422002) 相似文献
9.
Based on summer observations of stable isotope of precipitation at Muztagata, western China, during 2002-2003, this paper
presents the relationship between δ
18O in precipitation and air temperature, and discusses the effect of moisture transport on δ
18O in precipitation. Results show that air temperature correlates positively with δ
18O in precipitation, and the temperature effect controls the δ
18O of precipitation in this area. The Muztagata region exhibits high δ
18O values in summer precipitation, similar to those shown at stations in adjacent regions. According to the results of our
model set up to trace the moisture trajectories, the westerlies and local moisture circulation contribute to variations of
oxygen isotopes in precipitation. In addition, the impacts of the moisture transport distance, the moisture transport level,
and the incursion of the polar air mass also influence the variations of δ
18O in precipitation. The moisture origins and transport mechanisms also contribute to the variation of δ
18O in precipitation at Muztagata. 相似文献
10.
During the 22nd Chinese Antarctic Research Expedition (CHINARE-22), the atmospheric gas samples above the oceanic surface
and near the surface were collected on the track for the scientific ship “Xuelong” and on Millor Peninsula of eastern Antarctica, respectively, using the Tedlar gas bags. Every day the sampling times were
10:00 and 22:00 (local time), respectively. In the laboratory, high-precision measurement of the isotopic compositions for
N2O in these gas samples was conducted using Thermo Finnigan MAT-253 Isotopic Mass Spectrometer with a fully automated interface
for the pre-GC concentration (PreCon) of trace gases. The temporal and spatial variations of δ
15N and δ
18O in atmospheric N2O were analyzed. The mean δ
15N and δ
18O-N2O values above the oceanic surface were (7.21±0.50)‰ and (44.52±0.52)‰, respectively. From 30°N to Antarctica, the δ
15N (6.05‰–7.88‰) linearly increased with the rate of about 0.01‰ with the latitude while the δ
18O (43.05‰–48.78‰) showed a large fluctuation. The δ
15N negatively correlated with air temperature and N2O concentration, and slightly positively correlated with δ
18O. The summertime variations of δ
15N and δ
18O-N2O appeared the same trend on Millor Peninsula of eastern Antarctica. They significantly positively correlated with each other
and negatively with N2O concentration. The δ
15N and δ
18O-N2O at different sites averaged (7.42±0.35)‰ and (44.69±0.49)‰, respectively, slightly higher than those above the oceanic surface,
significantly higher than those of atmospheric N2O in the low-latitude regions of Northern Hemisphere. The predominant factors affecting the spatial variations of δ
15N and δ
18O values were also discussed. The isotopic data given in this study can help to investigate the global and regional N2O budgets.
Supported by the National Natural Science Foundation of China (Grant Nos. 40676005 and 40406001) 相似文献
11.
The secular variations (SV) ing
1
0
of geomagnetic field, caused by the interaction between the geomagnetic field and the radial fluid-flow of the outer-core,
are discussed with both statistical and analytic methods. When the value ofg
1
0
s
2
0
is relatively high compared with other terms, SV ing
1
0
is characterized by exponential change. When the effect of non-dipole field is notable, SV ing
1
0
shows complex features. Especially when the value of g
1
0
is close to zero, SV ing
1
0
is completely determined by the random process of non-dipole fields.
Project supported by the National Natural Science Foundation of China (Grant No. 49429405) and by the Chinese Academy of Sciences. 相似文献
12.
对Cr6+胁迫条件下不同pH处理对菹草无菌苗元素、光合色素、活性氧、丙二醛、抗氧化酶、脯氨酸(Pro)及多胺(PAs)含量的影响进行研究,以探讨不同pH处理影响水生植物Cr6+毒害效应的机制.结果表明:(1)偏酸性pH处理加剧菹草对铬的蓄积,而pH为7.0时Cr6+胁迫所造成的矿质元素失衡有所减弱;(2)Cr6+胁迫下pH为6.0~8.0的处理延缓了菹草的失绿症状,促进了光合色素的合成;(3)Cr6+胁迫下菹草超氧化物歧化酶、过氧化氢酶的活性在pH为6.0和7.0的处理组诱导程度最小;(4)Cr6+胁迫下pH为6.0和7.0处理的菹草Pro含量显著提高;(5)pH为4.0和5.0的处理使腐胺(Put)含量显著提高,而pH为6.0和7.0的处理则促进亚精胺(Spd)含量及游离态(Spd+Spm)/Put比值上升,精胺(Spm)含量总体趋势为随pH值升高而逐步上升,仅在pH为4.0和5.0的处理组中低于Cr6+胁迫对照组.因此,pH条件可影响菹草对铬及营养元素的积累,抗氧化酶、Pro、PAs代谢等生理生化过程,导致铬毒性效应差异.在pH为6.0~7.0的范围内,菹草能调节抗氧化酶系统,较有效地清除体内活性氧,提高机体中Pro、PAs含量及游离态(Spd+Spm)/Put比值,减轻膜系统脂质过氧化,维持机体内矿质元素平衡,致使毒性效应达到最小程度. 相似文献
13.
Expeditions to Muztagata (in the eastern Pamirs) during the summer seasons of 2002 and 2003 collected precipitation samples
and measured their oxygen isotopes. The δ
18O in precipitation displays a wide range, varying from −17.40‰ to +1.33‰ in June-September 2002 and from −22.31‰ to +4.59‰
in May-August 2003. The δ
18O in precipitation correlates with the initial temperature of precipitation during the observing periods. The positive correlation
between δ
18O and temperature suggests that δ
18O can be used as an indicator of temperature in this region. The δ
18O values in fresh-snow samples collected from two snow events at different elevations on the Muztagata Glacier show a strong
“altitude effect”, with a ratio of nearly −0.40% per 100 m from 5500 m to 7450 m. 相似文献
14.
Morita T Ohtsuka Y Fujimoto K Minamisako Y Iida R Nakamura M Kayama T 《Marine pollution bulletin》2010,60(12):2311-2322
The anthropogenic radionuclides, 137Cs, 90Sr, 108mAg, 239+240Pu, were measured in two Chionoecetes species, red queen crab (Chionoecetes japonicus) and snow crab (Chionoecetes opilio) collected around Japan during 1996–2007. There was no increase in the concentrations of these radionuclides and no large variation of the atom ratio of 240Pu/239Pu during this research period. These results indicated that the source of the radionuclides was not the radioactive wastes dumped by the former USSR and Russia and originated from past nuclear weapon tests. The higher atom ratio in the crab species than that from global fallout would be contributed by the Pacific Proving Grounds close-in fallout. The variability of the concentration of radionuclides in the crab species would result from the variability of the composition and quantity in the diet. However, the decrease in the concentration of radionuclides with sampling depth would depend on the concentration in the seawater and diet. 相似文献
15.
A temporal and spatial change of codaQ
–1 associated with the occurrence of the North Palm Springs earthquake of July 8, 1986 was studied by using 242 small local earthquakes in the vicinity of the mainshock. We found that the codaQ
–1 of earthquakes which occurred before the mainshock was significantly higher than that of the aftershocks in the mainshock area while the codaQ
–1 for the surrounding area remained almost constant throughout 1986. CodaQ
–1 was determined separately for the lapse time windows of 10 to 20 sec. and 15 to 40 sec. for the period from 1981 to 1987. The result for the time window 10 to 20 sec. showed a peak in codaQ
–1 before the time of mainshock at all frequencies. The peak appeared earlier at lower frequencies. There was no significant change in codaQ
–1 for the time window 15 to 40 sec., probably because the change was restricted to a small area. 相似文献
16.
17.
18.
Hu Yi-li Xu Jun Duan Yong-kong Xu Zhao-yong Yang Run-hai Zhao Jin-ming 《地震学报(英文版)》2004,17(6):725-734
A new method of detecting the vertical bearing capacity for single-pile with high strain is discussed in this paper. A heavy
hammer or a small type of rocket is used to strike the pile top and the detectors are used to record vibration graphs. An
expression of higher degree of strain (deformation force) is introduced. It is testified theoretically that the displacement,
velocity and acceleration cannot be obtained by simple integral acceleration and differential velocity when long displacement
and high strain exist, namely when the pile phase generates a whole slip relative to the soil body. That is to say that there
are non-linear relations between them. It is educed accordingly that the force P and displacement S are calculated from the amplitude of wave train and (dynamic) P-S curve is drew so as to determine the yield points. Further, a method of determining the vertical bearing capacity for single-pile
is discussed. A static load test is utilized to check the result of dynamic test and determine the correlative constants of
dynamic-static P(Q)-S curve.
Foundation item: Key projects of the tenth Five-year Plan of Yunnan Province (documented Yunnan district [2002]54-02-02) and Geophysical
Society of Yunnan Province. 相似文献
19.
对2021年5月21日云南漾濞M5.6、M6.4及M5.2地震中获取的120条强震动观测记录进行处理及分析,给出获取记录的地震动参数,绘制峰值加速度等值线分布图,发现其长轴均成NW-SE方向展布。将3次地震实际PGA观测值与俞言祥~([1])、汪素云~([2])地震动衰减关系进行对比,发现实际观测值与俞言祥预测值更吻合。对比分析典型台站的加速度反应谱,发现震级愈大,长周期分量愈明显;震级愈小,幅值衰减愈快。 相似文献
20.
Alexander Ruzmaikin Anvar Shukurov Dmitry Sokoloff Sergey Starchenko 《地球物理与天体物理流体动力学》2013,107(1-3):125-139
Abstract We propose a method of derivation of global asymptotic solutions of the hydromagnetic dynamo problem at large magnetic Reynolds number. The procedure reduces to matching the local asymptotic forms for the magnetic field generated near individual extrema of generation strength. The basis of the proposed method, named here the Maximally-Efficient-Generation Approach (MEGA), is the assertion that properties of global asymptotic solutions of the kinematic dynamo are determined by the distribution of the generation strength near its leading extrema and by the number and distribution of the extrema. The general method is illustrated by the global asymptotic solution of the α2-dynamo problem in a slab. The nature of oscillatory solutions revealed earlier in numerical simulations and the reasons for the dominance of even magnetic modes in slab geometry are clarified. Applicability of the asymptotic solutions at moderate values of the asymptotic parameter is also discussed. We confirm this applicability using comparisons with complementary asymptotic expansions and numerical simulations. In particular, this justifies application of the MEGA solutions to estimation of the generation threshold. 相似文献