Fault plane solutions of microearthquakes and small events in the Hellenic arc     

Michael L. Jost  Olaf Knabenbauer  Jin Cheng  Hans-Peter Harjes   《Tectonophysics》2002,356(1-3)

The Hellenic arc is the most active seismic region of the transition zone between the African and Eurasian plates. In this rapidly deforming region, the physical state of the crust and upper mantle may vary laterally and vertically. However, a detailed 3D model of the region is lacking. The reliable determination of fault plane solutions is crucial if such a model is to be produced. On this basis, fault plane solutions have been determined from recent microearthquakes and small events to assess their reliability for use in tectonic interpretation. A search algorithm on first motion data and amplitude ratios and also a waveform-matching scheme were employed on data from our temporal network, operated on the western part of the island of Crete. There, a network of 47 three-component digital stations with an aperture of 60 km and an average station spacing of 5 km was operated in 1997. The majority of the shallow microearthquakes under Crete for which fault plane solutions were determined have a near horizontal T-axis oriented essentially E–W. Differences between well determined fault plane solutions from the search algorithm and the waveform-matching technique were significant (strike up to 45°, dip up to 10°, and slip up to 50°). Second, data of small events within the Hellenic subduction zone were obtained from recently installed broadband stations at local and regional distances and inverted for a deviatoric seismic moment tensor. Available solutions from other sources such as the Harvard group, EMSC, or SED show drastic differences in part. Owing to still limited azimuthal station coverage, the resulting fault plane solutions of small events have generally not been well constrained. The observed large variation of fault plane solutions for micoearthquakes and small events poses a caveat to tectonic interpretation in case of using data from a few stations only.  相似文献   

Water level changes along the Norwegian coast     

Hans-Peter Plag 《Marine Geophysical Researches》1984,7(1-2):283-297

The water level records of 11 stations from the Norwegian coast having the recording interval 1971–1972 in common have been analysed with a least squares algorithm. The results for the harmonic constants are compared to open ocean tide models and a good agreement is found. The variation of tidal parameters and mean sea level are calculated from a 70 years water level record from Bergen. An 18.6 yearly variation in amplitude and phase of the fortnightly tide Mf could be identified. Cross correlation techniques are used to investigate the nontidal part of the water level changes. Correlating the residuals of the analyses with each other, the main nontidal water level changes are found to be moving from south to north along the Norwegian coast, taking 20 hours to reach from Stavanger to Vadsø. The effect of local air pressure on sea level is modelled using transfer functions. Mean sea level changes in Bergen are found to correlate with changes in length of day and changes in global surface temperature.  相似文献   

Intercomparison of Two Hydroxyl Radical Measurement Techniques at the Atmosphere Simulation Chamber SAPHIR     

Eric Schlosser  Birger Bohn  Theo Brauers  Hans-Peter Dorn  Hendrik Fuchs  Rolf Häseler  Andreas Hofzumahaus  Frank Holland  Franz Rohrer  Lutz Olaf Rupp  Manfred Siese  Ralf Tillmann  Andreas Wahner 《Journal of Atmospheric Chemistry》2007,56(2):187-205

At the atmosphere simulation chamber SAPHIR in Jülich both Laser-Induced Fluorescence Spectroscopy (LIF) and Long-Path Differential Optical Laser Absorption Spectroscopy (DOAS) are operational for the detection of OH radicals at tropospheric levels. The two different spectroscopic techniques were compared within the controlled environment of SAPHIR based on all simultaneous measurements acquired in 2003 (13 days). Hydroxyl radicals were scavenged by added CO during four of these days in order to experimentally check the calculated precisions at the detection limit. LIF measurements have a higher precision (σ= 0.88×10⁶ cm^–3) and better time resolution (Δt = 60 s), but the DOAS method (σ= 1.24×10⁶ cm^–3, Δt = 135 s) is regarded as primary standard for comparisons because of its good accuracy. A high correlation coefficient of r = 0.95 was found for the whole data set highlighting the advantage of using a simulation chamber. The data set consists of two groups. The first one includes 3 days, where the LIF measurements yield (1 – 2) ×10⁶ cm^–3 higher OH concentrations than observed by the DOAS instrument. The experimental conditions during these days are characterized by increased NO_x concentration and a small dynamic range in OH. Excellent agreement is found within the other group of 6 days. The regression to the combined data of this large group yields unity slope without a significant offset.  相似文献   

A goal-based approach to the identification of essential transformation variables in support of the implementation of the 2030 agenda for sustainable development     

Hans-Peter Plag  Shelley-Ann Jules-Plag 《International Journal of Digital Earth》2020,13(2):166-187

ABSTRACT

The United Nations' 2030 Agenda for Sustainable Development sets seventeen Sustainable Development Goals (SDGs) to be achieved by 2030. Earth observation are needed that can support the development and validation of transformation policies to make progress towards the SDGs. A participatory and inclusive goal-based approach (GBA) is introduced that links societal goals, targets and indicators to Essential Transformation Variables (ETVs) of the human and non-human environment. The GBA is complementary to the widely used expert-based approach. The GBA is applied to the SDGs at the goal, target and indicator levels. The high-level conceptual model used for the SDGs is humanity embedded in the Earth's life-support system (ELSS). At the goal level, very few of the SDGs are directly focusing on the ELSS and its physiology. Most of the SDG Targets focus on transformations in society and the built environment. Having targets that explicitly focus on the physiology of the ELSS would be important for sustainability. Most of the current indicator measure the built environment and the embedded social fabric. Sustainable development requires a functioning ELSS, and to ensure this, complementary indicators that bring environmental aspects to the monitoring of SDG targets are needed.  相似文献   

Rock-weathering by lichens in Antarctic: patterns and mechanisms     

Chen Jie Ph.D.  Hans-Peter Blume 《地理学报(英文版)》2002,12(4):387-396

Saxicolous species of lichens are able to induce and accelerate weathering of their rock substrate, and effects of lichens on substrate can be attributed to both physical and chemical causes. This paper is focused on biotic weathering actions of epilithic and endolithic species on the different rock types (sandstones and volcanogenic rocks) in Antarctica. The patterns, mechanisms, processes and neoformations of rock-weathering resulting from lichen colonization are expounded in detail. Furthermore, it is pointed out that, for a better understanding of the impacts of lichens on environments, the studies on the rate of biotic weathering and the comprehensive involvement of the lichen effects on weathering of natural rocks remain to be carried out in Antarctica.  相似文献   

人类活动对南极陆地生态系统的影响   总被引：12，自引：2，他引：10       下载免费PDF全文

陈杰 《极地研究》2000,12(1):62-74

由于科学考察活动日益频繁以及旅游业在南极地区的迅速开展 ,人类活动对南极陆地生态系统的影响在最近几十年内一直倍受国际社会的关注。在广泛收集国外有关资料的基础上 ,本文对人类活动引发的南极地区区域性的土壤与植被污染、野生动物受扰、外来物种引进、以及细菌性疾病侵入等方面进行了论述。同时 ,阐述了南极以外地区的人为污染源对南极环境的潜在威胁。最后 ,对“南极条约体系”与国际社会为保护南极环境所作出的不懈努力进行了简要介绍与评价。  相似文献