从印尼地震海啸看防震减灾宣传教育工作的作用和发展方向

本文以印尼8．7级强烈地震引发的海啸灾害的惨痛教训为切入点,启迪各级领导和社会公众深刻认识加强防震减灾宣传教育工作,不仅能减轻地震灾害造成的人员伤亡和经济损失,而且对保障国民经济建设健康、持续发展和社会稳定将起着积极的不可替代的作用,对构建和谐社会具有重要的现实意义和深远的历史意义。     

九江-瑞昌5.7级地震调查及其思索和启示

扼要介绍了该次地震基本特征,分析了房屋破坏和地震地表变形的可能原因,指出在中国东部尤其是以往被视为少震弱震的地区完善地震监测设施、加强地震预测预报研究、普及避震抗震知识、注重建构筑物尤其是民居群选址工作和落实必要的抗震结构措施的必要性和紧迫性。     

Break in the Indian summer monsoon

Summary The changes in circulation patterns over Eurasia during break monsoon condition over India are studied in comparison to the active monsoon condition. Break monsoon condition seems to set in over the India Sub-Continent in association with eastward movement of middle latitude westerly trough at 500 mb, having large amplitude extending into west Pakistan and northern India. Simultaneously the subtropical anticyclonic ridge over Arabia protrudes into central and Peninsular India. The high latitude blocking high over East Siberia retrogrades and the East Asiatic trough deepens and moves eastwards. The west Pacific subtropical ridge recedes eastward from the China continent. During this period the monsoon trough shifts, from its normal position over Gangetic plains, northwards to the foot of the Himalayas and the monsoon westerlies in the lower troposphere extends right upto the rim of the Tibetan Plateau. The sub-tropical ridge line in the upper troposphere shifts northwards during break and lies approximately above the lower monsoon trough. This seems to provide an effective process of removing ascending air in the lower monsoon trough causing exceptionally heavy rainfall over Assam and along the foot of the Himalayas.     

Some studies in the resistivity of Indian sandstones

Summary In this paper some measurements of the resistivity of Talchir and Barakar sandstones of the Jharia Coal field under dry and saturated conditions have been made and the results are discussed in the light of known theories. Techniques of measurement have been briefly described.     

江苏防震减灾网客户端访问统计分析

对2005年改版后的江苏防震减灾网站访问流量进行多方位的统计,并通过统计数据对地震专业网站浏览者的情况做全面的分析,从而为地震专业网站今后的开发平台和发展方向提供有效的依据。     

Variations of the lunar geomagnetic tide in the Indian region

The seasonal variations of the lunar geomagnetic tide are analysed at a group of stations around the longitude of India. The position of the focus of the lunar ionospheric current system is found to move with season and to disappear in northern winter. A year-to-year variability of the phases is also demonstrated. The phase relationships indicate the presence of antisymmetric atmospheric tidal modes of various strengths in different seasons. The different lunar Hough mode amplitudes, derived earlier, may also explain the observed September maximum in the lunar horizontal magnetic component at the equator.     

Possible role of warming on Indian summer monsoon precipitation over the north-central Indian subcontinent

ABSTRACT

Broad disagreement between modelled and observed trends of Indian summer monsoon (ISM) over the north-central part of the Indian subcontinent (NCI) implies a gap in understanding of the relationship between the forcing factors and monsoonal precipitation. Although the strength of the land–sea thermal gradient (LSG) is believed to dictate monsoon intensity, its state and fate under continuous warming over the Bay of Bengal (BoB) and part of the NCI (23–28°N, 80–95°E) are less explored. Precipitation (1901–2017) and temperature data (1948–2017) at different vertical heights are used to understand the impact of warming in the ISM. In NCI, surface air temperature increased by 0.1–0.2°C decade^?1, comparable to the global warming rate. The ISM precipitation prominently weakened and seasonality reduced after 1950, which is caused by a decrease in the LSG at the depth of the troposphere. Warming-induced increase in local convection over the BoB further reduced ISM precipitation over NCI.     

Probabilistic Assessment of Earthquake Hazards in the Indian Subcontinent

—The Indian subcontinent is one of the most seismic prone areas of the world. The Himalayan mountains in the north, mid-oceanic ridges in the south and earthquake belts surrounding the Indian plate all show that the subcontinent has undergone extensive geological and tectonic processes in the past. The probability of the occurrence of earthquakes with magnitude 6<Mb<7 during a specified interval of time has been estimated on the basis of four probabilistic models namely Lognormal, Weibull, Gamma and Exponential distribution for the Indian subcontinent. The seismicity map has been prepared using the earthquake catalogue from the period 1963–1994, and six different zones have been identified on the basis of clustering of events. The model parameters have been estimated by the method of maximum likelihood estimates (MLE) and method of moments (MOM). A computer program package has been developed for all four models, which represents the distributions of time intervals fairly well. The logarithmic of likelihood (ln L) is estimated for testing the models and different models have been found to be plausible. The probability of different magnitude thresholds has been evaluated using the Gutenberg–Richter formula Log N = a - bM for magnitude distribution. The constants a and b have been computed for each region and found to be varying between 5.46–8.53 and 0.87–1.34, respectively.     

The relationship between significant wave height and Indian Ocean Dipole in the equatorial North Indian Ocean

Based on reanalysis data, we find that the Indian Ocean Dipole (IOD) plays an important role in the variability of wave climate in the equatorial Northern Indian Ocean (NIO). Significant wave height (SWH) in the equatorial NIO, especially over the waters southeast to Sri Lanka, exhibits strong interannual variations. SWH anomalies in the waters southeast to Sri Lanka correlate well with dipole mode index (DMI) during both summer and autumn. Negative SWH anomalies occur over the oceanic area southeast to Sri Lanka during positive IOD events and vary with different types of IOD. During positive prolonged (unseasonable) IOD, the SWH anomalies are the strongest in autumn (summer); while during positive normal IOD, the SWH anomalies are weak in both summer and autumn. Strong easterly wind anomalies over the southeast oceanic area of Sri Lanka during positive IOD events weaken the original equatorial westerly wind stress, which leads to the decrease in wind-sea waves. The longer wave period during positive IOD events further confirms less wind-sea waves. The SWH anomaly pattern during negative IOD events is nearly opposite to that during positive IOD events.