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71.
本文对1988年6月四川省道孚八美(即乾宁)4.5、5.0、4.0级地震前后地震活动进行了研究,给出了地震参数、P波初动解、余震序列和前兆变化的分析及未来地震危险性的讨论。 相似文献
72.
本文在水化前兆清理研究的基础上,采用统一的异常判别方法,应用适合本地区的“异常可靠性评价标准”,对新疆乌鲁木齐地区150km范围内的中强地震和反例事件进行了深入剖析,对水化异常与地震三要素的关系进行了统计分析。研究结果是制定地震水化异常判据和定量化指标的基础。 相似文献
73.
Kiyoo Mogi 《Pure and Applied Geophysics》1988,126(2-4):447-463
Before the 1944 Tonankai earthquake along the Nankai Trough, seismic activity increased in the shallow depths, and then the activity gradually migrated downwards. When it reached its limit (a depth of approximatelty 70 km), the main shock occurred. Several deep earthquakes, including one ofM5.3, occurred several months prior to the Tonankai earthquake. A similar downward migration pattern also can be recognized regarding the 1952 Tokachi-oki earthquake. In this case the deepest earthquakes reached about 400 km. This may be one of the intermediate-term precursory phenomena of great thrusttype earthquakes in subduction zones. Recent observations in the Tokai district along the Suruga Trough, where a large earthquake is expected to occur in the future, suggest a similar downward migration pattern in the land area. 相似文献
74.
Nitrogen and sulfur species in Antarctic aerosols at Mawson,Palmer Station,and Marsh (King George Island) 总被引:4,自引:0,他引:4
D. L. Savoie J. M. Prospero R. J. Larsen F. Huang M. A. Izaguirre T. Huang T. H. Snowdon L. Custals C. G. Sanderson 《Journal of Atmospheric Chemistry》1993,17(2):95-122
High volume bulk aerosol samples were collected continuously at three Antarctic sites: Mawson (67.60° S, 62.50° E) from 20 February 1987 to 6 January 1992; Palmer Station (64.77° S, 64.06° W) from 3 April 1990 to 15 June 1991; and Marsh (62.18° S, 58.30° W) from 28 March 1990, to 1 May 1991. All samples were analyzed for Na+, SO
4
2–
, NO
3
–
, methanesulfonate (MSA), NH
4
+
,210Pb, and7Be. At Mawson for which we have a multiple year data set, the annual mean concentration of each species sometimes vary significantly from one year to the next: Na+, 68–151 ng m–3; NO
3
–
, 25–30 ng m–3; nss SO
4
2–
, 81–97 ng m–3; MSA, 19–28 ng m–3; NH
4
+
, 16–21 ng m–3;210Pb, 0.75–0.86 fCi m–3. Results from multiple variable regression of non-sea-salt (nss) SO
4
2–
with MSA and NO
3
–
as the independent variables indicates that, at Mawson, the nss SO
4
2–
/MSA ratio resulting from the oxidation of dimethylsulfide (DMS) is 2.80±0.13, about 13% lower than our earlier estimate (3.22) that was based on 2.5 years of data. A similar analysis indicates that the ratio at Palmer is about 40% lower, 1.71±0.10, and more comparable to previous results over the southern oceans. These results when combined with previously published data suggest that the differences in the ratio may reflect a more rapid loss of MSA relative to nss SO
4
2–
during transport over Antarctica from the oceanic source region. The mean210Pb concentrations at Palmer and Marsh and the mean NO
3
–
concentration at Palmer are about a factor of two lower than those at Mawson. The210Pb distributions are consistent with a210Pb minimum in the marine boundary layer in the region of 40°–60° S. These features and the similar seasonalities of NO
3
–
and210Pb at Mawson support the conclusion that the primary source regions for NO
3
–
are continental. In contrast, the mean concentrations of MSA, nss SO
4
2–
, and NH
4
+
at Palmer are all higher than those at Mawson: MSA by a factor of 2; nss SO
4
2–
by 10%; and NH
4
+
by more than 50%. However, the factor differences exhibit substantial seasonal variability; the largest differences generally occur during the austral summer when the concentrations of most of the species are highest. NH
4
+
/(nss SO
4
2–
+MSA) equivalent ratios indicate that NH3 neutralizes about 60% of the sulfur acids during December at both Mawson and Palmer, but only about 30% at Mawson during February and March. 相似文献
75.
76.
77.
由岩体失稳讨论地震前兆的复杂性 总被引:9,自引:0,他引:9
断层带应变弱化——失稳的地震模式表明,岩体失稳不仅取决于作用的应力水平,而且决定于应变弱化阶段中环境刚度和岩石刚度的相对大小。该模式可能被应用去解释实际观测中出现异常,而其后不发生地震活动的复杂情况。 相似文献
78.
COMPARISON OF AEROSOL CHARACTERISTICS OVER MAINLAND OF CHINA AND WESTERN PACIFIC AND ITS LONG-RANGE TRANSPORT 下载免费PDF全文
Wen Yupu Yang Shaojin Yang Yinan Chen Bingru Zhou Mingyu Zheng Yueming Zhang Ziyu Yu Hongjian 《Acta Meteorologica Sinica》1991,5(2):160-170
Based on the aerosol data obtained at Shangdianzi regional background monitoring station together withthe air trajectory analysis,the chemical constituents of the aerosol from the different sources are discussed andcompared with the aerosol samples collected over the western Pacific.The results show that the relative massconcentrations of the crustal and pollutant elements in the aerosol collected over the ocean are higher than thosebeing observed at Shangdianzi in particle size above 4.7 μm and below 0.65μm in diameter.The variationsof the enrichment factors of these elements in marine aerosol with particle size are different from those in shang-dianzi's samples.The former enrichment factors are evidently higher than the latter above 1.1 μm in diameter.On the basis of the comparative research,the long-range transport processes of aerosol particles are discussed. 相似文献
79.
本文根据江苏省东台市Jiang港农场综合地震测报点微观观测虎皮鹦鹉的实验资料,详细介绍了1985年以来记录到的两次地震前鹦鹉异常反应。并对观测条件和方法、资料的可靠性、异常指标的确定,地震前兆异常与非震异常特征及其鉴别方法等分别作了介绍和讨论,还对动物的微观观测可能成为监视地震的一种有希望的短临前兆手段,进行了估评。 相似文献
80.