An eruption of the veer cone as a volcanic event during the increase of volcanic activity in Kamchatka at the beginning of the Christian Era

Tephrochronologic studies conducted in the Levaya Avacha River valley helped determine the true age of the Veer cinder cone, which formed approximately in 470 AD (1600 ¹⁴C BP). These data refute the existing idea that it was generated in 1856. The monogenetic Veer cone should be cancelled from the catalogs of historical eruptions and active volcanoes in Kamchatka. The eruption of this cone was a reflection of the all-Kamchatkan increase in the activity of endogenous processes that occurred in 0–650 AD.     

A modern vision: Eric Lindsay at Armagh

Eric Mervyn Lindsay masterminded the development of Armagh Observatory in the middle of the 20th century, building it into the centre for research and education that it is today. John McFarland recounts Lindsay's story, of how one man's drive and ambition forged international collaborations that presaged today's world of shared research facilities     

Nature of sudden auroral activations at the beginning of magnetic storms

Certain large magnetic lays, registered by magnetometers in the auroral and subauroral zones simultaneously with SC instant and accompanying events, substantially differ from activations at the beginning of auroral substorm. Such basic substorm elements as energy accumulation during the growth phase and breakup—activation in the localized region near midnight—are absent. During such sudden auroral activations (SAs), a disturbance begins in a wide sector of longitudes and latitudes. It is proposed to combine SAs into an individual class of magnetospheric disturbances. The particle acceleration and injection mechanism, which causes SAs, is considered.     

A versatile index to characterize hysteresis between hydrological variables at the runoff event timescale

This study presents a versatile index for the quantification of hysteretic loops between hydrological variables at the runoff event timescale. The conceptual development of the index is based on a normalization of the input data and the computation of definite integrals at fixed intervals of the independent variable. The sum, the minimum and the maximum of the differences between integrals computed for the rising and the falling curves provide information on the direction, the shape and the extent of the loop. The index was tested with synthetic data and field data from experimental catchments in Northern Italy. Hysteretic relations between streamflow (the independent variable) and soil moisture, depth to water table, isotopic composition and electrical conductivity of stream water (dependent variables) were correctly identified and quantified by the index. The objective quantification of hysteresis by the index allows for the automatic classification of hysteretic loops and thus the determination of differences in hydrological responses during different events. The index was also used to examine the seasonal dynamics in the relation between streamflow and soil moisture and captured the switch in the direction of the loop with changes in event size and antecedent wetness conditions. The sensitivity of the index to the temporal resolution of the measurements and measurement errors was also tested. The index can successfully quantify hysteresis, except for very noisy data or when the temporal resolution of the measurements is not well suited to study hysteresis between the variables. Copyright © 2015 John Wiley & Sons, Ltd.     

Luminescence dating of a gigantic palaeolandslide in the Gobi-Altay mountains, Mongolia

In an attempt to date a palaeolandslide that took place along the Baga Bogd Massif, in Mongolia, the infrared stimulated luminescence (IRSL) method has been applied to lacustrine silty sediments directly overlying the landslide mass. The IRSL age estimates obtained on alkali feldspar grains (>40 μm) and polymineral fine grains (4–11 μm) provide a minimum age for the landslide event. The IRSL ages on alkali feldspars corrected for long-term fading using the protocol of Mejdahl (1988, 1989) suggest that the palaeolandslide occurred at the beginning of the Last Interglacial. These are in good agreement with the ¹⁰Be cosmogenic dates obtained on faulted and abandoned alluvial fans in the Gobi-Altay mountains. This study demonstrates for the first time that the IRSL dating method can successfully be applied for establishing landslide chronologies.     

A flux transfer event observed at the magnetopause by the Equator-S spacecraft and in the ionosphere by the CUTLASS HF radar

Observations of a flux transfer event (FTE) have been made simultaneously by the Equator-S spacecraft near the dayside magnetopause whilst corresponding transient plasma flows were seen in the near-conjugate polar ionosphere by the CUTLASS Finland HF radar. Prior to the occurrence of the FTE, the magnetometer on the WIND spacecraft ≈226 R_E upstream of the Earth in the solar wind detected a southward turning of the interplanetary magnetic field (IMF) which is estimated to have reached the subsolar magnetopause ≈77 min later. Shortly afterwards the Equator-S magnetometer observed a typical bipolar FTE signature in the magnetic field component normal to the magnetopause, just inside the magnetosphere. Almost simultaneously the CUTLASS Finland radar observed a strong transient flow in the F region plasma between 78° and 83° magnetic latitude, near the ionospheric region predicted to map along geomagnetic field lines to the spacecraft. The flow signature (and the data set as a whole) is found to be fully consistent with the view that the FTE was formed by a burst of magnetopause reconnection.     

Source parameters of four strong earthquakes in Bulgaria and Portugal at the beginning of the 20th century

Using original seismograph records and bulletin data we re-determined theorigin time, location, seismic moment (M₀) and magnitudes(M_S and M_w) for four earthquakes in the beginning of the20th century. These are two strong earthquakes April 4, 1904 nearKrupnik, Bulgaria (M_w = 6.8, M_S = 7.2 respectively), the April 231909 earthquake near Benavente, Portugal (M_S = 6.3), and the June14, 1913 earthquake near Gorna Orjahovitza, Bulgaria (M_S = 6.3).Twenty-nine traces from original records have been analysed, a largenumber of original station bulletins have been consulted and a consistentmethodology for analysing these early 20th century instrumentalinformation is presented.In spite of a thorough effort in re-assembling and quality control of theoriginal data, large inaccuracies remain in the improved instrumentalepicentre locations and origin times. The seismic moment estimates weobtained (2.3 10¹⁸ M₀ 3.9 10¹⁹Nm) are the first ever determined for these events. The magnitudeestimates (6.3 M_S 7.2 and 6.2 M_w 7.0) are robust and systematically lower than most of previousestimates for all earthquakes (Gutenberg and Richter, 1954; Christoskovand Grigorova, 1968; Karnik, 1969). For the largest Krupnik event ourestimates agree with those of Abe and Noguchi (1983b) and Pacheco andSykes (1992). The studied earthquakes all occur in moderately seismicactive regions, therefore our results may have significant consequences forhazard estimates in those regions.     

典型的太阳质子事件峰值流量的一种预报方法

分析了1988~2006年中62个典型的太阳质子事件,发现其归一化后峰值流量变化具有很好的统计规律,根据该规律提出了一种对太阳质子事件峰值流量进行预报的方法.试验预报结果表明,太阳质子事件峰值流量的预报值和实测值都在同一个量级以内,平均相对误差为32％,预报误差在可接受范围内.本文方法对于日常预报业务而言是实用和可行的.     

2013年平流层爆发性增温期间高纬电离层半日潮汐波研究

基于Sondrestrom站(67°N, 51°W)非相干散射雷达观测数据, 研究了2013年平流层爆发性增温(SSW)事件发生后高纬地区电离层F层和E层半日潮汐波.同时, 对1月非SSW发生期间和不同太阳活动期间高纬电离层中的半日潮汐波进行了统计分析, 并和2013年SSW事件发生后的结果进行了比较.研究发现, SSW发生后F层经向风中的半日潮汐波有显著增强, 其振幅大于80 m·s^-1的时间持续了至少60 h, 最大值达到109 m·s^-1.在180~330 km范围内, 半日潮汐波振幅平均大了24 m·s^-1.在E层高度上, 经向风中的半日潮汐波也在SSW发生后迅速增强, 最大值达到109 m·s^-1, 在108~117 km范围内, 其振幅平均大了33 m·s^-1.在E层纬向风中, 半日潮汐波振幅在120 km处连续超过36 h的时间内大于70 m·s^-1, 最大值达到92 m·s^-1.不同太阳活动期间的半日潮汐波统计结果显示, 和低太阳活动期间相比, 高太阳活动期间半日潮汐波在F层和E层平均增强14 m·s^-1.这明显小于SSW期间24和33 m·s^-1的增幅, 表明高太阳活动不是2013年SSW期间高纬电离层半日潮汐波增强的主要原因.我们的研究表明2013年高纬电离层半日潮汐波的增强很可能是受到SSW事件的影响.

     

A short-lived aeolian event during the Early Holocene in southeastern Norway

The Starmoen dune field is part of a larger aeolian system in the Jømna and Glomma river valleys in southeastern Norway. It is believed to have formed just after the last deglaciation in the area, but no absolute ages have been available to support this. Here, we present a set of quartz optically stimulated luminescence (OSL) ages from the aeolian sediments and the underlying glacifluvial deposits. The results show that the main dune-building phase was a short-lived event ∼10 ka ago, likely with a duration less than a few hundred years. This suggests a rapid stabilisation of an initially unstable environment in newly deglaciated terrain. A much younger event with limited and surficial reworking of sand is dated to 770 ± 110 years ago, and the modern age of an active dune provide additional OSL quality control. Age overestimation is found for glacifluvial sediments, probably due to incomplete bleaching as indicated by e.g. scattered dose distributions from small aliquots. OSL measurements were conducted using coarse quartz grains (180–250 m), which show a dominance of a fast signal component.     

Estimation of particle velocity based on blast event measurements at different rock units

This paper analyses the results of the peak particle velocity measurements, at the trial, construction and quarry blasting carried out in sediment rock deposits comprising mainly limestone and dolomite. The tests are divided into 3 groups depending on different geological strength index (GSI) values in these rock groups. Based on the results of seismic measurements the empirical relationships between peak particle velocity and scaled distance were established for each group. In order to establish a useful relationship between peak particle velocity and scaled distance, a simple regression analysis was conducted with the Blastware software program from Instantel. The established relationships and the results of those analyses are presented in this paper.     

我国现代地震台网观测技术的开拓者

引言 张奕麟先生是我国现代地震台网观测技术的开拓者和奠基人之一.20世纪60年代至90年代,他致力于现代模拟和数字地震台网观测技术研究,为推动我国地震观测技术现代化做出了突出贡献.本文就他在北京八条线遥测地震台网、国家地震局768工程,以及中国数字地震台网(CDSN)等科技项目中,发挥的历史作用做简要回顾.     

A detailed paleomagnetic survey of the type location for the Gilsa geomagnetic polarity event

A total of 163 cores have been taken from a maximum of 40 separate lavas in three separate sections of the Jökuldalur, southwest of Egilsstadir, Iceland, and subjected to paleomagnetic analysis and some K-Ar dating. Previous work on the sections by McDougall and Wensink (1966) led to the establishment of the Gilságeomagnetic polarity event, with an age of about 1.60 m.y., during the reversed polarity Matuyama epoch. This earlier study described a possible reversely magnetized lava separating the Gilsáevent from a second normal polarity lava, perhaps representing the Olduvai event. Such a possibility was subsequently a source of speculation from diverse sources concerning the polarity history for the lower Matuyama. The present study indicates clearly that there is no second normal polarity event represented in the sections. Only one normal polarity event is therefore represented in the lower Matuyama of the Jökuldalur, and the age of the lavas involved is confirmed to be approximately 1.58 ± 0.08 m.y. Because of uncertainties in the interpretation of the original K-Ar results from Olduvai Gorge, it is still not possible to be certain that the Olduvai and Gilsáevents are separated in time. An incidental result of the survey is evidence to show that, contrary to recent suggestions by Einarsson (1972), there is no substantial hiatus between the major lower parts of the section and lavas believed to represent extrusions after a regional tilting and peneplanation.     

全面禁止核试验条约（CTBT）科学技术大会（SnT）的科学议程和地震事件性质识别研究进展

全面禁止核试验条约组织（Comprehensive Nuclear-Test-Ban Treaty Organization,CTBTO）科学技术大会（Science and Technology Conference,SnT）致力于推进禁核试的科技进步,依靠科技创新来加强《全面禁止核试验条约》（Comprehensive Nuclear-Test-Ban Treaty,CTBT）的条约核查制度能力,加快条约生效进程。鉴于地震学是禁核试监测的重要手段以及SnT大会的科学进展有助于检视地震科技的发展,本文系统分析了SnT大会的科学议题设置以及SnT大会中地震事件性质识别等研究进展。分析表明,SnT大会主题中的 “地球复杂系统” 和 “传感器与网络技术” ,以及禁核试监测手段中的地震学手段更受关注。事件性质识别研究始终是与CTBT相关的地震学的核心问题,其在朝鲜系列核试验事件的应用研究也同样是关注的焦点问题,而深度学习和机器学习等新技术在事件性质识别研究中展示了较快的发展趋势。      

Spatial variability of floodplain sedimentation at the event scale in the Rhine–Meuse delta,The Netherlands

This article addresses spatial variability of comtemporary floodplain sedimentation at the event scale. Measurements of overbank deposition were carried out using sediment traps on 11 floodplain sections along the rivers Waal and Meuse in The Netherlands during the high-magnitude flood of December 1993. During the flood, sand sheets were locally deposited behind a natural levee. At distances greater than 50 to 100 m from the river channel the deposits consisted mainly of silt- and clay-sized material. Observed patterns of deposition were related to floodplain topography and sediment transporting mechanisms. Though at several sites patterns were observed that suggest transport by turbulent diffusion, convection seems the dominant transporting mechanism, in particular in sections that are bordered by minor embankments. The average deposition of overbank fines ranged between 1·2 and 4·0 kg m⁻² along the river Waal, and between 1·0 and 2·0 kg m⁻² along the river Meuse. The estimated total accumulation of overbank fines (not including sand sheets) on the entire river Waal floodplain was 0·24 Mton, which is 19 per cent of the total suspended sediment load transported through the river Waal during the flood. © 1998 John Wiley & Sons, Ltd.     

Relationship between point rainfall, average sampled rainfall and ground truth at the event scale in the Sahel

Geostatistical techniques are used to quantify the reference mean areal rainfall (ground truth) from sparse raingaugenetworks. Based on the EPSAT-Niger event cumulative rainfall, a linear relationship between the ground truth considered as the mean area rainfall estimated from the densely available raingauge network and the area rainfall estimated from sparse network are derived. Also, a linear relationship between the ground truth and point rainfall is established. As it was reported experimentally by some authors, the slope of these relationships is less than one. Based on the geostatistical framework, the slope and the ordinate at the origin can be estimated as a function of the spatial structure of the rainfall process. It is shown that the slope is smaller than one. For the special case of one gauge inside a fixed area or a Field Of View (FOV), an areal reduction factor is derived. It has a limit value which depends only on the size of the area and the spatial structure of the rainfall process. The relative variance error of estimating the FOV cumulative rainfall from point rainfall is also given.