Volcanica http://www.jvolcanica.org/ojs/index.php/volcanica <p><em>Volcanica</em>&nbsp;seeks to publish high-quality, rigorously peer reviewed research pertaining to volcanology and related disciplines, while eliminating submission fees and keeping content freely accessible.</p> en-US <p>Submission of an original manuscript to <em>Volcanica&nbsp;</em>will be taken to mean that it represents original work <strong>not previously published</strong>, and <strong>not being considered for publication elsewhere</strong>.&nbsp;</p> jifarq89@googlemail.com (Jamie Farquharson) farquharson@jvolcanica.org (Jamie Farquharson) Wed, 22 Aug 2018 17:25:36 +0000 OJS http://blogs.law.harvard.edu/tech/rss 60 Field evidence for the lateral emplacement of igneous dykes http://www.jvolcanica.org/ojs/index.php/volcanica/article/view/13 <p>Seismological and geodetic data from modern volcanic systems strongly suggest that magma is transported significant distance (tens of kilometres) in the subsurface away from central volcanic vents.&nbsp; Geological evidence for lateral emplacement preserved within exposed dykes includes aligned fabrics of vesicles and phenocrysts, striations on wall rocks and the anisotropy of magnetic susceptibility.&nbsp; In this paper, we present geometrical evidence for the lateral emplacement of segmented dykes restricted to a narrow depth range in the crust.&nbsp; Near-total exposure of three dykes on wave cut platforms around Birsay (Orkney, UK) are used to map out floor and roof contacts of neighbouring dyke segments in relay zones.&nbsp; The field evidence suggests emplacement from the WSW towards the ENE, and that the dykes are segmented over their entire vertical extent.&nbsp; Geometrical evidence for the lateral emplacement of segmented dykes is likely more robust than inferences drawn from flow-related fabrics, due to the prevalence of ubiquitous ‘drainback’ events (i.e. magmatic flow reversals) observed in modern systems.</p> David Healy, Roberto E Rizzo, Marcus Duffy, Natalie J C Farrell, Michael J Hole, David Muirhead ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 http://www.jvolcanica.org/ojs/index.php/volcanica/article/view/13 Wed, 22 Aug 2018 00:00:00 +0000 Trashcano: Developing a quantitative teaching tool to understand ballistics accelerated by explosive volcanic eruptions http://www.jvolcanica.org/ojs/index.php/volcanica/article/view/4 <div>Accurate predictions of volcanological phenomena, such as the trajectory of blocks accelerated by volcanic explosions, require quantitative skills training. Large outdoor experiments can be useful to convey concepts of volcanic&nbsp;processes to students in an exciting way. Beyond the fun aspects, these experiments provide an opportunity to&nbsp;engage with the physics of projectile flight and help promote mathematical learning within the Earth Sciences.&nbsp;We present a quantitative framework required to interpret ballistic trajectories and the outdoor experiment known&nbsp;commonly as “trashcano”, taking a step-by-step approach to the physics of this problem, and deriving a range&nbsp;of mathematical solutions involving different levels of complexity. Our solutions are consistent with the predictions from established computer programs for volcanic ballistic trajectory modelling, but we additionally provide&nbsp;a nested set of simplified solutions, useful for a range of teaching scenarios as well as downloadable simulated&nbsp;datasets for use where the full experiment may not be possible.</div> Fabian Ben Wadsworth, Holly E Unwin, Jérémie Vasseur, Ben M Kennedy, Julia Holzmueller, Bettina Scheu, Taylor Witcher, Janina Adolf, Francisco Cáceres, Ana S Casas, Valeria Cigala, Alexandra Clement, Mathieu Colombier, Shane Cronin, Marcel Cronin, Donald B Dingwell, Leticia F Guimarães, Laura Höltgen, Ulrich Kueppers, Gilles Seropian, Sönke Stern, Adrien Teissier, Caron Vossen, Natalie Weichselgartner ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 http://www.jvolcanica.org/ojs/index.php/volcanica/article/view/4 Tue, 18 Sep 2018 14:35:11 +0000 The different characteristics of the recent eruptions of Fernandina and Sierra Negra volcanoes (Galápagos, Ecuador) http://www.jvolcanica.org/ojs/index.php/volcanica/article/view/18 <p>After eight years of quiescence, Fernandina volcano experienced two short-lived eruptions, on 4 September 2017 and 16 June 2018. The eruptions were characterized by very short periods of unrest that started a few hours before the initiation of the eruptive activity. On the other hand, Sierra Negra volcano (Isabela Island) began a new eruptive period on 26 June 2018, after almost one year of persistent unrest characterized by an increase in the magnitude and number of seismic events and more than 5 meters of uplift since its last eruption in 2005. The Sierra Negra and Fernandina eruptions were located in remote zones where access is extremely complex. Thus, satellite images complement the continuous monitoring data of the Instituto Geofísico (IG-EPN) with remote observations and allow rapid response mapping in order to identify the areas affected by the lava flows. Finally, the aim of this Report is to encourage other scientists to investigate the behaviors of both pre-eruptive and eruptive periods registered during these eruptions.<span class="Apple-converted-space">&nbsp;</span></p> Francisco Javier Vasconez, Patricio Ramón, Stephen Hernandez, Silvana Hidalgo, Benjamin Bernard, Mario Ruiz, Alexandra Alvarado, Peter La Femina, Gorki Ruiz ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 http://www.jvolcanica.org/ojs/index.php/volcanica/article/view/18 Fri, 26 Oct 2018 00:00:00 +0000