地震灾情因社会发展而加重--20世纪全球地震灾害综述

２０世纪中国是世界上地震灾害最严重的国家。地震造成的经济损失最严重的是日本,美国,中国居第二,三位。全世界地震灾情有逐世纪加重的趋势。地震减灾研究有两点进展;１．中国有一次成功的临震预报;２．日本抗震建筑有效。全世界的未来地震灾情形势依然严峻。     

关注日本地震预报研究20年

基于所了解的情况，对20世纪最后20年日本地震预报研究的一些情况进行了回顾。     

Stratigraphic records of tsunamis along the Japan Sea,southwest Hokkaido,northern Japan

The stratigraphy of tsunami deposits along the Japan Sea, southwest Hokkaido, northern Japan, reveals tsunami recurrences in this particular area. Sandy tsunami deposits are preserved in small valley plains, whereas gravelly deposits of possible tsunami origin are identified in surficial soils covering a Holocene marine terrace and a slope talus. At least five horizons of tsunami events can be defined in the Okushiri Island, the youngest of which immediately overlies the Ko‐d tephra layer (1640 AD) and was likely formed by the historical Oshima‐Ohshima tsunami in 1741 AD. The four older tsunami deposits, dated using accelerator mass spectrometry ¹⁴C, were formed at around the 12th century, 1.5–1.6, 2.4–2.6, and 2.8–3.1 ka, respectively. Tsunami sand beds of the 1741 AD and circa 12th century events are recognized in the Hiyama District of Hokkaido Island, but the older tsunami deposits are missing. The deposits of these two tsunamis are found together at the same sites and distributed in regions where wave heights of the 1993 tsunami (Hokkaido Nansei‐oki earthquake, Mw = 7.7) were less than 3 m. Thus, the 12th century tsunami waves were possibly generated near the south of Okushiri Island, whereas the 1993 tsunami was generated towards the north of the island. The estimated recurrence intervals of paleotsunamis, 200–1100 years with an average of 500 years, likely represents the recurrence interval of large earthquakes which would have occurred along several active faults offshore of southwest Hokkaido.     

卫星远程医疗在抗震救灾中的应用

以２０世纪我国灾难性大地震和１９９５年日本阪神·淡路大震灾分析为例,阐述了卫生远程医疗在抗震救灾中的重要作用和应用前景。     

日本朔望时刻记载及其对地球自转变化研究的可能贡献

历史上采用地方时间（如地方视太阳时、平太阳时等）观测和记录的某些天象的时刻,可用于地球自转速率变化的研究．日本在１７—１９世纪间有许多月球朔和望时刻的观测记录．本文简要介绍了其记载情况,探讨了将这些年代较晚的观测资料用于地球自转速率变化研究的可能性．试算结果表明他们对研究此期间地球自转速率的变化可起到积极作用．有必要对他们作更深入的研究．     

Asperity Distribution of the 1952 Great Kamchatka Earthquake and its Relation to Future Earthquake Potential in Kamchatka

—The 1952 Kamchatka earthquake is among the largest earthquakes of this century, with an estimated magnitude of M _w = 9.0. We inverted tide gauge records from Japan, North America, the Aleutians, and Hawaii for the asperity distribution. The results show two areas of high slip. The average slip is over 3 m, giving a seismic moment estimate of 155×10²⁰Nm, or M _w = 8.8. The 20th century seismicity of the 1952 rupture zone shows a strong correlation to the asperity distribution, which suggests that the large earthquakes (M > 7) are controlled by the locations of the asperities and that future large earthquakes will also recur in the asperity regions.     

二十世纪的地球偶极子磁场

1900~2000年的IGRF(国际地磁参考场)资料使研究20世纪中地磁场的变化规律成为可能,在20世纪中,即使从19世纪起,地球偶极子磁场发生了较大的变化,偶极矩一直保持衰减的势头,地心轴的所有3个分量都是减小的.地磁南极的位置变化在1930年左右发生大的转折,1960年起向西和向南快速移动,偶极子轴在纬度方面变化只有1°左右,经度变化在3°左右,离磁极倒转的条件差得远.     

Reconstruction of the Wolf Numbers Based on Radiocarbon Data from the Early 11th Century until the Middle of the 19th Century with Respect to Climate Changes

Geomagnetism and Aeronomy - The results of the reconstruction of Wolf numbers from the 11th century until the middle of the 19th century A.D. based on radiocarbon data are presented. This time span...     

1995年1月17日日本兵库县南部地震概况综述

１９９５年１月１７日,强烈的日本兵库县南部地震袭击了日本近畿地方的广大地区,这次灾难性的地震是半个世纪以来在日本发生的规模最大的一次内陆地震,它使日本遭受了一次出乎意料的严重破坏,打破了“日本安全”的神话,将对今后的地震预报和防灾对策研究产生重大的影响,因此,这次地震引起了日本和世界各国的极大关注。本文将对这次地震作一综合介绍。     

Geodesy in Japan

T. Inoh was the first who completed a nation-wide map of Japan, in the beginning of the 19th century. He determined geodetic positions by distance and angle measurements and by astronomical observations. When Japan entered into its modern era, about 100 years ago, the Military Land Survey was established and has conducted geodetic work in Japan ever since until the end of World War II. A German surveying system belonging to Helmert's school was adopted. The Ministry of Education organized later the Geodetic Commission which promoted the geodetic activities in cooperation with the Military Land Survey. Comparison between the first and second nation-wide triangulation results obtained by the Geographical Survey Institute (GSI), the successor of the Military Land Survey, brought out marked horizontal land-deformations associated with a large earthquake. Repetitions of levelling survey also make it clear that vertical land-movements, well consistent with tide-gauge observation data, take place in association with earthquakes. The extensive subsidence in the Northeast Japan may be explained by assuming a sinking lithosphere, as is argued by the theory of plate tectonics. On the other hand, most local movements are closely correlated to pre-, co- and post-seismic land-deformations. The nation-wide gravity survey carried out by the GSI disclosed a complicated gravity distribution in Japan. Ship-borne gravimeters have now been extensively working at sea. One of the recent highlights of gravimetric work is the detection of secular gravity changes which are in accordance with the secular changes of levelling data. A portable absolute-gravity measuring instrument was constructed by the Earthquake Research Institute although it is still in a testing stage. Much advance has been made in the astrogeodetic observation devices since 1950's.     

1840年以来长江大洪水演变与气候变化关系初探

长江洪水灾害是我国频率高、为患严重的自然灾害之一.本文依据可靠资料,选择1840年至2000年间32次大洪水记录,探讨其演变与气候变化的关系.认知1910s前的19世纪冷期出现大洪水13次(包括1870年的极值大洪水事件)频率为1.9次／10a.1921-2000年间出现了大洪水19次,频率为2.4次／10a.20世纪暖期又分出两个变暖时段,前一变暖时段的峰值期1920s-1940s出现大洪水9次,包含1931年全流域大洪水.后一变暖时段,即1980s与1990s出现大洪水8次.实测记录到的最大洪水1954年位于前一变暖时段结束阶段.1990s是全球,也是我国近百年中最暖年代,受东南季风影响大的中下游地区夏季降水量是近百年最多的,大暴雨频率也是有较多记录的40年来最高的.以此出现了10年5次大洪水高频率现象,包含1998年全流域型大洪水,表明了全球变暖的显著影响.也指示30-40年问周期性振荡中多雨年代.如此可预期21世纪初期降水会有小幅度下降与大洪水频率在短期内降低的可能性.长江上游受西南季风影响较大,19世纪下半期与20世纪上半期为多降水期,大洪水频率较高.20世纪下半期为少降水期,大洪水频率较低.关于气候变化研究有待深入,前景不易预估.     

Climatic and environmental changes at southeastern coast of Lake Biwa over past 3000 years, inferred from borehole temperature data

In order to infer past climatic change in central Japan, we measured temperatures in a borehole at the Karasuma site, on the southeastern coast of Lake Biwa, and reconstructed sediment surface temperature history during the last 3000 years. The reconstructed temperature history shows apparent Medieval Warm Period, Little Ice Age, and contemporary temperature warming. However, the large amplitude of the temperature changes up to 4-5 K cannot be explained by past climatic change only, suggesting that there was some other cause of the larger amplitude temperature changes. The onsets of temperature decrease in the late 12th century a.d. and temperature increase in the mid 17th century a.d. appear to coincide with occurrences of two destructive earthquakes (1185 and 1662 a.d.) that caused water level changes of Lake Biwa. It suggests that the reconstructed sediment surface temperature history reflects the environmental change due to tectonically induced water level changes of the lake. If the annual mean of the ground surface temperature was higher than that of the bottom water temperature in a shallow part of the lake, which is consistent with the present-day data, the large amplitude of the sediment surface temperature change may be attributed to a combined effect of past climatic and environmental changes. Thus, we suggest that the borehole temperature at the Karasuma site preserves information not only on past climate changes but also on environmental changes due to tectonically induced water level changes.     

Reconstruction of autumn sea ice extent changes since AD1289 in the Barents-Kara Sea,Arctic

Using high-resolution ice core and tree ring proxies for sea ice extent(SIE), we reconstructed a robust time series of autumn SIE over the Barents-Kara(B-K) sector of the Arctic from AD1289–1993. After intercomparing the results and statistical parameters using the ordinary least squares regression(OLSR), the principle component regression(PCR) and the partial least squares regression(PLSR) methods, SIE time series were synthesized into a more robust series using the weighted average method, which used the explained variances as weights. The results showed that from the end of the 13 th century to the end of18 th century, the autumn B-K SIE was large, with large variations and a slightly expanding trend overall. This reflected significant multidecadal oscillations under the Little Ice Age(LIA) background. The B-K SIE began to decrease at the end of the18 th century, and a shrinking trend became significant during the second half of the 19 th century, which lasted into the 1930 s–1940 s. The 1930 s–1940 s was a period with a relatively low SIE in the B-K Sea, and the SIE had a short period of expansion from the 1940 s–1970 s. However, the B-K SIE has continuously and significantly shrank since the 1970 s. The reduction in the B-K SIE since the end of the 18 th century has been unprecedented in both duration and speed over the last 700 years. The B-K SIE has retreated significantly since the 1970 s, with a speed 6.18 times greater than the former mean retreating speed. The industrial revolution may be a dominant factor in this result. The Arctic SIE in recent years may be the lowest it has been over the last millennium.     

Evolution of Views on the Structure of Sources of Strong Earthquakes at the End of XX and Beginning of XXI Centuries

Izvestiya, Physics of the Solid Earth - The evolution of scientific views on the structure of the sources of strong earthquakes at the end of the 20th and beginning of the 21th century in Russia is...     

Earthquake resistant construction techniques and materials on Byzantine monuments in Kiev

The study of the behaviour of historic buildings that have suffered from earthquakes has become a valuable tool for the understanding of earthquake resistant construction techniques and materials. Byzantine monuments of the 11–13th century in Kiev have been studied to provide insights into their effective dynamic properties facing severe earthquake history in the area. The recessed brickworks according to the “concealed course” construction technique of the St. Sophia Cathedral (11th century), the Church of St. Michael in the Vydubytskyi Monastery (11th century), the Tithe Church of the Assumption of the Virgin (10th century) and the Cathedral of Assumption of the Virgin (11th century) in the Monastery of the Caves (Pecherskyi monastery) in Kiev were studied and the material properties of bricks and lime mortars with ceramic fill were investigated (mechanical strength tests, mineralogical, chemical and microstructural analysis). The results show major similarities with those of the Byzantine monuments in Istanbul (Theodosian Walls and Hagia Sophia — 6–11th century construction phases), giving evidence of earthquake resistant construction techniques and materials allowing for continuous stresses and strains. Hence, didactics on proper restoration techniques and materials are deduced aiming at their present safety in the face of future earthquakes.     

气候变暖下太湖极端洪水的归因探讨

全球增温引起的降水变化是否引起极端洪水的增加,发生在不同气候背景的极端洪水事件可提供不同参照系;而不同驱动因子下气候、水文数值模拟为认识洪水发生和归因提供了有效途径.本文结合机理数值模拟和随机统计模拟两种途径,针对1990s和1880s的太湖流域特大洪水,通过GCM气候模拟驱动的流域水文模拟和不确定性的阈值模拟,分析19世纪末和20世纪末极端洪水的发生强度和频率的变化,从而论证极端洪水发生的风险系数.结果表明,1990s的极端洪水流量(0.1%的极端洪水流量(Q0.1%)为2929~3601 m³/s,0.5%的极端洪水流量(Q0.5%)为1842~1893 m³/s)比工业革命前大气温室气体状况下(Q0.1%为2069~3119 m³/s,Q0.5%为1436~1561 m³/s)显著增大.与19世纪末相比,由于太湖流域人类活动改变的流域下垫面在1999年特大洪水中引起最大增量占35%,本文模拟和分析的20世纪末气候下的洪水最大增量占60%.去除人类活动影响的下垫面变化,估计特大洪水风险的最大增量为25%,因此认为20世纪末气候变化引起的太湖极端洪水风险在增加;这将为认识与全球增温相关联的洪水灾害预测预警提供科学依据.     

20世纪地震预报科学的回顾与展望

在新世纪的到来,对２０世纪的地震研究作一些回顾,对中国几十年的地震预报的道路进行反思,可能是很有意义的,这对我们编制“十五”规划也有借鉴。     

Drifting runoff periodicity during the 20th century due to changing surface water volume

Fourier and wavelet analyses were used to reveal the dominant trends and coherence of a more than one‐century‐long time series of precipitation and discharge in several watersheds in Sweden, two of which were subjected to hydropower and intensive agriculture. During the 20th century, there was a gradual, significant drift of the dominant discharge periodicity in agricultural watersheds. This study shows that the steepness of the Fourier spectrum of runoff from the May to October period each year increased gradually during the century, which suggests a more predictable intra‐annual runoff pattern (more apart from white‐noise). In the agricultural watershed, the coherence spectrum of precipitation and runoff is generally high with a consistent white‐noise relationship for precipitation during the 20th century, indicating that precipitation is not controlling the drift of the discharge spectrum. In the hydropower regulated watershed, there was a sudden decrease of the discharge spectrum slope when regulation commenced in the 1920s. This study develops a new theory in which the runoff spectrum is related to the hydraulic and hydro‐morphological characteristics of the watershed. Using this theory, we explain the changes in runoff spectra in the two watersheds by the anthropogenic change in surface water volume and, hence, changes in kinematic wave celerity and water transit times. The reduced water volume in the agricultural watershed would also contribute to decreasing evaporation, which could explain a slightly increasing mean discharge during the 20th century despite the fact that precipitation was statistically constant in the area. Copyright © 2010 John Wiley & Sons, Ltd.     

Collision orogeny at arc-arc junctions in the Japanese Islands

Abstract In the Japanese Islands, collision tectonics are operating at arc-arc junctions in three regions: Hokkaido, Central Japan and Kyushu. Hokkaido is situated at the junction of the Kuril and Northeast Japan Arcs. The Kuril fore arc sliver collides with the Northeast Japan Arc, and the lower crust of the Kuril Arc thrusts upon the fore arc of the Northeast Japan Arc in Hokkaido. Outcrops of the lower crust are observed in the Hidaka Mountains in the fore arc of the junction area. Central Japan is in the juncture area among the Northeast Japan, Izu-Bonin, and Southwest Japan Arcs. The Izu-Bonin arc is colliding against the Honshu mainland, which has been bent by the collision. Kyushu is a juvenile collision area between the Southwest Japan and Ryukyu Arcs. The fore arc of the Southwest Japan Arc is starting to underthrust beneath the Kyushu islands along the Bungo Strait, where shallow seismicity within the crust is active in terms of the collision. Collision tectonics are observed at most of the arc-arc junctions in the circum-Pacific orogenic belts and may be an important process contributing to the relatively rapid growth of new continental crust in subduction zones.