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  • 1
    ISSN: 1432-0819
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The eruption that started in the Hekla volcano in South Iceland on 17 January 1991, and came to an end on 11 March, produced mainly andesitic lava. This lava covers 23 km2 and has an estimated volume of 0.15 km3. This is the third eruption in only 20 years, whereas the average repose period since 1104 is 55 years. Earthquakes, as well as a strain pulse recorded by borehole strainmeters, occurred less than half an hour before the start of the eruption. The initial plinian phase was very short-lived, producing a total of only 0.02 km3 of tephra. The eruption cloud attained 11.5 km in height in only 10 min, but it became detached from the volcano a few hours later. Several fissures were active during the first day of the eruption, including a part of the summit fissure. By the second day, however, the activity was already essentially limited to that segment of the principal fissure where the main crater subsequently formed. The average effusion rate during the first two days of the eruption was about 800 m3 s−1. After this peak, the effusion rate declined rapidly to 10–20 m3 s−1, then more slowly to 1 m3 s−1, and remained at 1–12 m3 s−1 until the end of the eruption. Site observations near the main crater suggest that the intensity of the volcanic tremor varied directly with the force of the eruption. A notable rise in the fluorine concentration of riverwater in the vicinity of the eruptive fissures occurred on the 5th day of the eruption, but it levelled off on the 6th day and then remained essentially constant. The volume and initial silica content of the lava and tephra, the explosivity and effusion rate during the earliest stage of the eruption, as well as the magnitude attained by the associated earthquakes, support earlier suggestions that these parameters are positively related to the length of the preceeding repose period. The chemical difference between the eruptive material of Hekla itself and the lavas erupted in its vicinity can be explained in terms of a density-stratified magma reservoir located at the bottom of the crust. We propose that the shape of this reservoir, its location at the west margin of a propagating rift, and its association with a crustal weakness, all contribute to the high eruption frequency of Hekla.
    Type of Medium: Electronic Resource
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  • 2
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    In:  Supplement to: Tarduno, John A; Duncan, Robert A; Scholl, David W; Cottrell, Rory D; Steinberger, Bernhard; Thordarson, Thorvaldur; Kerr, Bryan C; Neal, Clive R; Frey, Frederick A; Torii, Masayuki; Carvallo, Claire (2003): The Emperor Seamounts: Southward motion of the Hawaiian hotspot plume in earth's mantle. Science, 301(5636), 1064-1069, https://doi.org/10.1126/science.1086442
    Publication Date: 2024-01-09
    Description: The Hawaiian-Emperor hotspot track has a prominent bend, which has served as the basis for the theory that the Hawaiian hotspot, fixed in the deep mantle, traced a change in plate motion. However, paleomagnetic and radiometric age data from samples recovered by ocean drilling define an age-progressive paleolatitude history, indicating that the Emperor Seamount trend was principally formed by the rapid motion (over 40 millimeters per year) of the Hawaiian hotspot plume during Late Cretaceous to early-Tertiary times (81 to 47 million years ago). Evidence for motion of the Hawaiian plume affects models of mantle convection and plate tectonics, changing our understanding of terrestrial dynamics.
    Keywords: 19-192; 197-1203A; 197-1204B; 197-1205A; 197-1206A; Age, 40Ar/39Ar Argon-Argon; Age, dated; Age, dated standard deviation; Argon-40/Argon-36; Argon-40/Argon-36, standard deviation; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Event label; Glomar Challenger; Joides Resolution; Leg19; Leg197; North Pacific/GUYOT; North Pacific Ocean; Ocean Drilling Program; ODP; Sample code/label; Sample comment
    Type: Dataset
    Format: text/tab-separated-values, 222 data points
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  • 3
    Publication Date: 2021-01-27
    Description: When teaching at a non-English language universi- ty, we often argue that because English is the international language, students need to become familiar with English terms, even if the bulk of the class is in the native language. However, to make the meaning of the terms clear, a translation into the native language is always useful. Correct translation of terminology is even more crucial for emergency managers and decision makers who can be confronted with a confusing and inconsistently applied mix of terminology. Thus, it is im- perative to have a translation that appropriately converts the meaning of a term, while being grammatically and lexicologically correct, before the need for use. If terms are not consistently defined across all languages following indus- try standards and norms, what one person believes to be a dog, to another is a cat. However, definitions and translations of English scientific and technical terms are not always available, and language is constantly evolving. We live and work in an international world where English is the common language of multi-cultural exchange. As a result, while finding the correct translation can be difficult because we are too used to the English language terms, translated equivalents that are avail- able may not have been through the peer review process. We have explored this issue by discussing grammatically and lexicologically correct French, German, Icelandic, Indonesian, Italian, Portuguese, Russian, Spanish, and Japanese versions for terms involved in communicating effu- sive eruption intensity.
    Description: This is ANR-LAVA contribution no. 2.
    Description: Published
    Description: 57
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Description: JCR Journal
    Keywords: volcanology ; communication ; teaching ; translation ; Translations of volcanological terms ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
    Publication Date: 2022-11-23
    Description: The impact of Holocene eruptive events from hot spots like Iceland may have had significant global implications; thus, dating and knowledge of past eruptions chronology is important. However, at high-latitude volcanic islands, the paucity of soils severely limits 14C dating, while the poor K content of basalts strongly restricts the use of K/Ar and Ar/Ar methods. Even tephrochronology, based on 14C age determinations, refers to layers that rarely lie directly above lava flows to be dated. We report on the paleomagnetic dating of 25 sites from the Reykjanes Peninsula and the Tungnaá lava sequence of Iceland. The gathered paleomagnetic directions were compared with the available reference paleosecular variation curves of the Earth mag- netic field to obtain the possible emplacement age intervals. To test the method’s validity, we sampled the precisely dated Laki (1783–1784 AD) and Eldgjà (934–938 AD) lavas. The age windows obtained for these events encompass the true flow ages. For sites from the Reykjanes peninsula and the Tugnaá lava sequence, we derived multiple possible eruption events and ages. In the Reykjanes peninsula, we propose an older emplacement age (immediately following the 870 AD Iceland Settlement age) for Ogmundarhraun and Kapelluhraun lava fields. For pre-historical (older than the settlement age) Tugnaá eruptions, the method has a dating precision of 300–400 years which allows an increase of the detail in the chronostratigraphy and distribution of lavas in the Tugnaá sequence.
    Description: Published
    Description: 10
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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