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Apakah yang dapat dilakukan oleh ilmuan Yogyakarta terhadap Gunung Merapi dan lingkungan hidup di sekitarnya
No full text19 p.; 21 cm
Volcanic geology of Galunggung, West Java, Indonesia
Full text linkGalunggung volcano is located in West Java, Indonesia and covers an area about 275 km2. The volcano is very active and the slopes are highly populated (over 1.5 million people). There is therefore
always the threat of volcanic disaster. This study investigates the character of past Galunggung volcanic activity and assesses likely future activity in order to advise on volcanic hazard and risk. The
approach involves a study of stratigraphy, mineralogy and petrology of the Galunggung rocks, and the presentation of volcanic hazard zonation maps.
Galunggung volcanic rocks are included within the Galunggung Group and can be divided into Old Galunggung Formation, Tasikmalaya Formation and Cibanjaran Formation. The first formation represents rocks of Old Galunggung stratovolcano (50,000 - 10,000 yrs. BP ?), the second formation covers rocks erupted during caldera formation (4200 ± 150 yrs. BP) and the third one comprises rocks erupted in 1822, 1894, 1918 and 1982-83.
The Old Galunggung Formation consists mainly of pyroclastic flow, pyroclastic fall and lahar deposits and lava flows which have a total rock volume of about 56.5 km3. This activity ended with the intrusion of a cryptodome under the crater. The cryptodome blocked the existing vent and subsequent activity moved to the weakest part of the old cone to the ESE, resulting in the caldera forming-event. This destructive eruption formed a horseshoe-shaped caldera and ejected more than 20 km3 of material comprising debris avalanche, pyroclastic flow, pyroclastic fall, pyroclastic surge and lahar deposits. Historic eruptions separated by relatively long dormant periods produced less voluminous (< 0.4 km3) volcanic deposits.
Galunggung volcanic rocks are basalt (49 - 53 % SiO2) to basaltic andesite (53 - 57 % SiO2) having porphyritic textures with medium sized phenocrysts (15 - 40 %), mainly plagioclase (av. 18 %) and clinopyroxene (1.6 %). Olivine is observed in basic rocks, whereas orthopyroxene and magnetite are present in the most evolved rocks. Amphibole is common in pyroclastic deposits and gabbro clasts ejected during caldera formation.
On the basis of Mg contents, Galunggung rocks are divided into: 1. high-Mg basalt (12.5 10 % MgO) , 2. "Transitional" high-Mg basalt (9 - 6.5 % MgO) , 3. low-Mg basalt (< 6 % MgO), 4. high-Mg basaltic andesite (7 - 6 % MgO) and 5. low-Mg basaltic andesite (< 5 % MgO). The high-Mg basalts are subdivided into low-K high-Mg basalt (<0.4 % K2O) and medium-K high-Mg basalt (0.6 % K2O).
Alkali and incompatible elements increase whereas Mg, Fe, Ca and compatible trace elements decrease with increasing SiO2. The high-Mg basalts are the most primitive Galunggung rocks with highest Mg# = 75 - 69, Ni (up to 193 ppm), and Cr (711 ppm) but lowest incompatible elements. The "primitiveness" of the basalts is also reflected by their 230Th/232Th ratio (= 0.68) which is one of the lowest ratios yet found.
The Galunggung high-Mg basalts are considered to represent liquid compositions which have been derived from upper mantle peridotites. The low-K high-Mg basalt originate from spinel-peridotite by 15 % melting at about 50 km depth, and the medium-K high-Mg basalt from plagioclase-peridotite by 25 - 40 % melting at about 30 km depth. These primitive magmas probably rose rapidly to the surface as mantle "diapirs".
During Old Galunggung volcanic activity, low-K high-Mg basalt magma moved upward diapirically and formed a magma chamber in the crust at a depth of about 10 km. Fractionation of this magma formed
low-Mg basalts and basaltic andesites. This activity ended when a medium-K high-Mg basalt intruded as a cryptodome. Another low-K high-Mg basalt magma migrated into the crust and fractionated to produce low-Mg basalt basaltic andesite. Gas was trapped and high water pressure was attained; and amphibole gabbro solidified in the roof of the magma body. These rocks were erupted during the Galunggung caldera forming-event.
In 1982-83, a new generation of low-K high-Mg basalt magma was erupted. Fractionation in a conduit system changed compositions at the top part but not significantly in the lower part of the magma body. During the eruptive sequence firstly low-Mg basaltic andesite, then high-Mg basaltic andesite, "transitional" high-Mg basalt, and finally the low-K high-Mg basalt were erupted. Rhyolite pumice erupted in September 1982 is considered to be a product of melting of Miocene dacite by the high temperature (1300ºC) Galunggung high-Mg basalt magma.
Galunggung eruptions vary from non-violent effusive to destructive explosive events. These create hazards which are divided into four levels. First degree hazards are long-term and require further
study. In this thesis hazard maps are presented for second, third and fourth degree hazards. Evacuation routes are suggested away from the volcano as all arrangements must be planned well in advance of an actual event
volkanologi : buku teks bahan ajar untuk mahasiswa ilmu kebumian khususnya geologi
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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