scholarly journals Volcanic Deposits and Volcanic Hazard in Santo Domingo de Heredia, Costa Rica

2016 ◽  
Vol 8 (2) ◽  
pp. 111
Author(s):  
Martín Rojas-Barrantes ◽  
Mario Fernández-Arce
Keyword(s):  
Costa Rica ◽  
Volcanic Activity ◽  
Pyroclastic Flow ◽  
Volcanic Eruptions ◽  
Pyroclastic Flows ◽  
Eastern Region ◽  
Santo Domingo ◽  
Borehole Data ◽  
Volcanic Deposits ◽  
The Impact

The present research aims to investigate more precisely about the geology of the Eastern region of the Santo Domingo County. Santo Domingo is part of the structural plateau in the center of Costa Rica, which is located at the foot of the Cordillera Volcánica Central (CVF) [Central Volcanic Front] and is covered by volcanic deposits. On this plateau, called Central Valley, is the highest percentage of the population of the country and therefore, a large sector of the Costa Rican population is exposed to volcanic eruptions of the volcanoes in the CVF. For existing the national system for risk management and a law that demands actions to local authorities to prevent and mitigate disaster, it is necessary to identify the threats that exist in the cantons (counties) of Costa Rica. This will serve to take the prevention and mitigation actions necessary to reduce the impact of volcanic eruptions in the area of Santo Domingo.The research method consisted of review and analysis of previous works through literature research, data collection and analysis of boreholes from records of water-supply wells and open pits, and field work to better know the geology of the area. The results indicate that there are deposits of powerful volcanic eruptions of pyroclastic fall deposits (volcanic ash and lapilli) that mostly form clayey soils and lahars deposits that practically covers the entire territory. Underlying these deposits there is a pyroclastic flow deposit (ignimbrite), followed by lapilli tephra (a layer of pumice of at least 2 meters thick) that mark a change in the volcanic activity. Such pyroclastic flow is overlaid by an igneous presumably sub-volcanic activity of andesites interlayered with ancient tuffs, with a considerable thickness of over 350 meters according with borehole data and the exposure recognition on Pará river study sites. According to site locations (P1 to P23) of volcaniclastic deposits, there is evidence of an important environmental impact caused by the last eruptions of the CVF volcanoes. The real and current volcanic threat to the population of the County is the fall-out of ash emitted from the Turrialba and Irazú volcanoes. From local observations along the Virilla and Pará rivers sections, there is no evidence of younger pyroclastic flows overlying the volcanic sequence.

Health Impacts of Volcanic Activity in Oceania

2020 ◽  
Vol 35 (5) ◽  
pp. 574-578 ◽  
Author(s):  
Joseph Cuthbertson ◽  
Carol Stewart ◽  
Alison Lyon ◽  
Penelope Burns ◽  
Thompson Telepo
Keyword(s):  
New Zealand ◽  
Low Income ◽  
Volcanic Activity ◽  
Volcanic Eruptions ◽  
Pyroclastic Flows ◽  
Health Impacts ◽  
Low Income Countries ◽  
Access To Health Services ◽  
Wide Range ◽  
The Impact

AbstractVolcanoes cause a wide range of hazardous phenomena. Close to volcanic vents, hazards can be highly dangerous and destructive and include pyroclastic flows and surges, ballistic projectiles, lava flows, lahars, thick ashfalls, and gas and aerosol emissions. Direct health impacts include trauma, burns, and exacerbation of respiratory diseases. Far-reaching volcanic hazards include volcanic ashfalls, gas and aerosol dispersion, and lahars. Within Oceania, the island arc countries of Papua New Guinea (PNG), the Solomon Islands, Vanuatu, Tonga, and New Zealand are the most at-risk from volcanic activity. Since 1500ad, approximately 10,000 lives have been lost due to volcanic activity across Oceania, with 39 lives lost since 2000. While volcano monitoring and surveillance save lives, residual risks remain from small, sudden, unheralded eruptions, such as the December 9, 2019 eruption of Whakaari/White Island volcano, New Zealand which has a death toll of 21 at the time of writing. Widespread volcanic ashfalls can affect the habitability of downwind communities by contaminating water supplies, damaging crops and buildings, and degrading indoor and outdoor air quality, as well as disrupting transport and communication networks and access to health services. While the fatality rate due to volcanic eruptions may be low, far greater numbers of people may be affected by volcanic activity with approximately 100,000 people in PNG and Vanuatu displaced since 2000. It is challenging to manage health impacts for displaced people, particularly in low-income countries where events such as eruptions occur against a background of low, variable vaccination rates, high prevalence of infectious diseases, poor sanitation infrastructure, and poor nutritional status. As a case study, the 2017-2018 eruption of Ambae volcano, Vanuatu caused no casualties but triggered two separate mandatory off-island evacuations of the entire population of approximately 11,700 people. On the neighboring island of Santo, a health disaster response was coordinated by local government and provided acute care when evacuees arrived. Involving primary care clinicians in this setting enhanced local capacity for health care provision and allowed for an improved understanding of the impact of displacement on evacuee communities.

Phytoliths as an indicator of change in vegetation related to the huge volcanic eruption at 7.3 ka in the southernmost part of Kyushu, southern Japan

The Holocene ◽  
2021 ◽  
Vol 31 (5) ◽  
pp. 709-719
Author(s):  
Naoki Hayashi ◽  
Yudzuru Inoue ◽  
Tatsuichiro Kawano ◽  
Jun Inoue
Keyword(s):  
Pyroclastic Flow ◽  
Vegetation Change ◽  
Volcanic Eruptions ◽  
Pyroclastic Flows ◽  
Evergreen Forest ◽  
Study Region ◽  
Forest Sites ◽  
Before And After ◽  
Kyushu District

Volcanic eruptions can have a significant influence on adjacent ecosystems; however, little is known about the long-term vegetation change related to eruptions. In this study, we examined phytolith records in paleosols at multiple sites in the southern Kyushu District, Japan, to assess the influence of the Kikai caldera eruption 7300 years ago on vegetation. Our results show the vegetational difference before and after the eruption in the study region. Specifically, in the area where the pyroclastic flows distributed more thickly, the original evergreen forest was replaced by Andropogoneae grasslands after the eruption, which has been dominating the landscape in this area for at least 900 years. By contrast, in areas only mildly affected by pyroclastic flows, despite the temporary replacement of forest by grassland, the forest developed and flourished within several hundreds of years of the eruption. This is because a large amount of pyroclastic flow would have devastated all of the vegetation, whereas smaller amounts would have left some untouched forest sites within refugia. Our findings suggest that the vegetation varied significantly depending on the amount of pyroclastic flow reaching the area, even within the pyroclastic flow distributed region.

The 2019 July Stromboli volcano paroxysm event: contribution of infrasound to the Volcanic Ash Advisory Centers

2020 ◽  
Author(s):  
Emanuele Marchetti ◽  
Maurizio Ripepe ◽  
Alexis Le Pichon ◽  
Constantino Listowski ◽  
Lars Ceranna ◽  
...  
Keyword(s):  
Real Time ◽  
Volcanic Ash ◽  
Volcanic Eruptions ◽  
Volcano Monitoring ◽  
Pyroclastic Flows ◽  
Civil Aviation ◽  
Propagation Time ◽  
Stromboli Volcano ◽  
Eruptive Column ◽  
The Impact

<p>With the advent of civil aviation and growth in air traffic, the problem of volcanic ash encounter has become an issue of importance as a prompt response to volcanic eruptions is required to mitigate the impact of the volcanic hazard on aviation. Many volcanoes worldwide are poorly monitored, and most of the time notifications of volcanic eruptions are reported mainly based on satellite observations or visual observations. Among ground-based volcano monitoring techniques, infrasound is the only one capable of detecting explosive eruptions from distances of thousands of kilometers. On July 3 and August 28, 2019, two paroxysmal explosions occurred at Stromboli volcano. The events, that are similar in terms of energy and size to the peak explosive activity reported historically for the volcano, produced a significant emission of scoria, bombs and lapilli, that affected the whole island and fed an eruptive column that rose almost 5 km above the volcano. The collapse of the eruptive column also produced pyroclastic flows along the Sciara del Fuoco, a sector collapse on the northern flank of the volcano.</p><p>Being one of the best-monitored volcanoes of the world, the 2019 Stromboli paroxysmal explosions were observed in real-time and Civil Protection procedures started immediately. However, notification to the Toulouse Volcanic Ash Advisory Centre (VAAC) was not automated, and the VAA was issued only long after the event occurrence. The two explosions produced infrasound signals that were detected by several infrasound stations as far as Norway (IS37, 3380 km) and Azores islands (IS42, 3530 km). Despite of the latency due to the propagation time, infrasound-based notification arrays precedes the Volcanic Ash Advisories (VAAs) issued by Toulouse VACC. Following the same procedure applied for the Volcano Information System developed in the framework of the ARISE project, we show how infrasound array analysis could allow automatic, near-real-time identification of these eruptions with timely reliable source information. We highlight the need for an integration of the CTBT IMS infrasound network with local and regional infrasound arrays capable of providing a timely early warning to VAACs. This study opens new perspectives in volcano monitoring and could represent, in the future, an efficient tool in supporting VAACs activity.</p>

Preliminary absolute paleointensity estimation from a single volcanic-glass grain extracted from an unwelded pyroclastic flow

2020 ◽  
Author(s):  
Yuhji Yamamoto ◽  
Hiromi Takeda ◽  
Masahiko Sato ◽  
Hiroshi Kawabata
Keyword(s):  
Pyroclastic Flow ◽  
Remanent Magnetization ◽  
Volcanic Glass ◽  
Volcanic Eruptions ◽  
Natural Remanent Magnetization ◽  
Primary Component ◽  
Pyroclastic Flows ◽  
Isothermal Remanent Magnetization ◽  
Inflection Points ◽  
Stable Characteristic

<p>Many pyroclastic flows are distributed around Japan. They usually involve volcanic-glass grains. These grains are considered to form at the timing of volcanic eruptions and are expected to have magnetic inclusions consisting of tiny single (titano)magnetites with recording the paleomagnetic field. We have extracted single volcanic-glass grains of pumice-type with a diameter of 0.60-0.84 mm from an unwelded part of the Ito pyroclastic flow deposits (A-Ito, 26-29 ka; Machida and Arai, 2003), Kyusyu, Japan. A series of rock- and paleomagnetic measurements have been made on the grains.</p><p>Sixty-seven out of 88 grains had detectable intensities of natural remanent magnetization. Some of such grains were further investigated. Results of low-temperature magnetometry exhibited inflection points at 105-120 K, suggesting magnetite as a main remenence carrier. Stepwise alternating field demagnetization revealed an existence of stable characteristic remanence (ChRM) which was interpreted to be a primary component. </p><p>Tsunakawa-Shaw method (Tsunakawa and Shaw, 1994; Yamamoto et al., 2003), one of the latest absolute paleointensity (API) techniques to date, was applied to selected grains having stable ChRMs. On the application we newly included measurements related to an isothermal remanent magnetization (IRM). Four successful results were obtained by an adoption of IRM corrections, giving an average API value of about 25 μT. This corresponds to a virtual axial dipole moment (VADM) of about 50 ZAm<sup>2</sup>, which is consistent with the contemporaneous VADM of the sedimentary record (PISO-1500; Channell et al., 2009). </p>

scholarly journals Tsunami generation in Stromboli island and impact on the south-east Tyrrhenian coasts

2003 ◽  
Vol 3 (5) ◽  
pp. 299-309 ◽  
Author(s):  
S. Tinti ◽  
G. Pagnoni ◽  
F. Zaniboni ◽  
E. Bortolucci
Keyword(s):  
Source Region ◽  
Volcanic Eruptions ◽  
Pyroclastic Flows ◽  
Tyrrhenian Sea ◽  
Tsunami Generation ◽  
Tsunami Propagation ◽  
Fine Grid ◽  
North West ◽  
The North ◽  
The Impact

Abstract. Stromboli is one of the most active volcanoes in the Aeolian island arc in south Tyrrhenian sea, Italy. In the last 100 years the most relevant volcanic eruptions have beenaccompanied by local tsunamis, that have caused damage and casualties. In some cases the direct mechanism of local tsunami generation is clear, i.e. pyroclastic flows entering the sea. In some others it is uncertain and some speculation concerning the collapse of the eruptive column on the sea surface or the failure of some underwater mass can be made. But the ordinary activity is unlikely to generate large regional tsunamis. These can be produced by the lateral collapse of the volcanic cone that geomorphological and volcanological  investigations have proven to have occurred repeatedly in the recent history of the volcano, with return period in the order of some thousands of years. The last episode is dated to less than 5 ka BP, and left the Sciara del Fuoco scar on the north-west flank of Stromboli. Based on previous studies, the possible collapse of the nortwestern sector of Stromboli and the consequent generation and propagation of a tsunami are explored. The impact on Stromboli and on the other islands of the Aeolian archipelago is estimated, as well as the impact on the coast of Sicily and the Tyrrhenian coasts of Calabria. The simulation is carried out by means of a double model: a Lagrangian block model to compute the motion of the collapsing mass, and a finite-element hydrodynamic model to compute the evolution of the tsunami. Two distinct tsunami simulations are carried out, one on a very fine grid around the source region to evaluate the tsunami near Stromboli, and one utilising a coarser grid covering the whole south-east Tyrrhenian sea to compute the tsunami propagation toward Sicily and Calabria. It is found that a huge-volume collapse of the north-western flank of the Stromboli cone is capable of producing a regional tsunami which is catastrophic at the source and devastating on long stretches of Tyrrhenian coasts, but particularly in the neighbouring islands of Panarea and Salina, and along the Calabria coasts around Capo Vaticano.

scholarly journals An image of death in dinosaur faces caught in a pyroclastic flow from a local sub-event of the Chicxulub impact

2021 ◽  
pp. 7
Keyword(s):  
Pyroclastic Flow ◽  
Volcanic Eruption ◽  
Pyroclastic Flows ◽  
Volcanic Arc ◽  
Sea Floor ◽  
South Eastern ◽  
Impact Area ◽  
Mild Temperature ◽  
Chicxulub Impact ◽  
The Impact

The following paper builds on already observed dinosaur remains killed in a volcanic eruption linked to the Chicxulub in the area of Valbonne in south eastern France. The Chicxulub impact catapulted a number of sub-blocks from the crust around its impact area in the Yucatan far from it, their brutal landing triggered smaller tectonic waves. In Valbonne, which is a marginal area of the older Alpine volcanic arc, the dormant volcanism was waked up, as the block itself had been catapulted from the sea floor and was heavily hydrated, causing powerful and sudden pyroclastic flows with a mild temperature and catastrophic amounts of mud materials, intermediary to a lahar, which surprised a large number of dinosaurs. Their bodies were partly burned and aplasted and partly filled up with tephras mixed with hot materials from the impact, or andesitic mud-lava for farther away creatures.

Modelling aspects of the sulfate aerosol evolution after recent volcanic activity

2021 ◽  
Author(s):  
Christina Brodowsky ◽  
Timofei Sukhodolov ◽  
Aryeh Feinberg ◽  
Michael Höpfner ◽  
Thomas Peter ◽  
...  
Keyword(s):  
Volcanic Activity ◽  
Climate Model ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Sulfate Aerosol ◽  
Global Climate Models ◽  
Volcanic Plume ◽  
Free Running ◽  
Volcanic Emission ◽  
The Impact

<p>Volcanic activity is one of the main natural climate forcings and therefore an accurate representation of volcanic aerosols in global climate models is essential. However, direct modelling of sulfur chemistry, sulfate aerosol microphysics and transport is a complex task involving many uncertainties including those related to the volcanic emission magnitude, vertical shape of the plume, and observations of atmospheric sulfur. This study aims to investigate some of these uncertainties and to analyse the performance of the aerosol-chemistry-climate model SOCOL-AERv2 for three medium-sized volcanic eruptions from Kasatochi in 2008, Sarychev in 2009 and Nabro in 2011. In particular, we investigate the impact of different estimates for the initial volcanic plume height and its SO2 content on the stratospheric aerosol burden. The influence of internal model variability and of modelled dynamics is addressed by three free-running simulations and two nudged simulations at different vertical resolutions. Comparing the modelled evolution of the stratospheric aerosol loading and its spread with the Brewer-Dobson-Circulation (BDC) to satellite measurements reveals in general a very good performance of SOCOL-AERv2 during the considered period. However, the large spread in emission estimates logically leads to significant differences in the modelled aerosol burden. This spread results from both the uncertainty in the total emitted mass of sulfur as well as its vertical distribution relative to the tropopause. An additional source of modelled uncertainty is the tropopause height, which varies among the free-running simulations. Furthermore, the validation is complicated by disagreement between different observational datasets. Nudging effects on the tropospheric clouds were found to affect the tropospheric SO2 oxidation paths and the cross-tropopause transport, leading to increased background burdens both in the troposphere and the stratosphere. This effect can be reduced by nudging only horizontal winds but not temperature. A higher vertical resolution of 90 levels (as opposed to 39 in the standard version) increases the stratospheric residence time of sulfate aerosol after low-latitude eruptions by reducing the diffusion speed out of the tropical reservoir. We conclude that the model's uncertainties can be largely defined by both its set-up as by the volcanic emission parameters.</p>

The Impact of using 3D Interactive Animation Tool in Teaching Computer Programming at the Senior High School Level

2018 ◽  
Vol 3 (2) ◽  
pp. 18-28
Author(s):  
Najim Ussiph ◽  
Hamidu Kwame Seidu
Keyword(s):  
High School ◽  
Research Work ◽  
Instructional Method ◽  
Senior High School ◽  
School Level ◽  
Eastern Region ◽  
3D Animation ◽  
High School Level ◽  
Significant Difference ◽  
The Impact

A quasi experiment with interview was adopted to study the aptness of using 3D animations as an instructional method to introduce programming concepts to students at the Senior High School level. This research work was conducted with 100 students of Akroso Senior High School in the Birim central municipality of the eastern region of Ghana who were generally programming novice. Programming concepts considered included programming environments, loops, functions sequential and conditional execution of programs. A paired t-test carried out on the results of the performance test presents a p-value of 0.008 indicative of a numerically significant difference between the mean marks of participants during the experiments that used 3D animation method as against the experiments that used the text base method. Results from the interview showed that the instructional method used had impact on the performance of the learners. The use of 3D animation method presented programming concepts in a form that the learners can understand, motivates them to pursue programming related courses at a higher level and also impacts positively on their performance.

scholarly journals Evaluating Forest Cover and Fragmentation in Costa Rica with a Corrected Global Tree Cover Map

2020 ◽  
Vol 12 (19) ◽  
pp. 3226
Author(s):  
Daniel Cunningham ◽  
Paul Cunningham ◽  
Matthew E. Fagan
Keyword(s):  
Costa Rica ◽  
Forest Cover ◽  
Agricultural Land ◽  
Forest Area ◽  
Tree Cover ◽  
Agricultural Crop ◽  
Forest Change ◽  
Alos Palsar ◽  
Tropical Regions ◽  
The Impact

Global tree cover products face challenges in accurately predicting tree cover across biophysical gradients, such as precipitation or agricultural cover. To generate a natural forest cover map for Costa Rica, biases in tree cover estimation in the most widely used tree cover product (the Global Forest Change product (GFC) were quantified and corrected, and the impact of map biases on estimates of forest cover and fragmentation was examined. First, a forest reference dataset was developed to examine how the difference between reference and GFC-predicted tree cover estimates varied along gradients of precipitation and elevation, and nonlinear statistical models were fit to predict the bias. Next, an agricultural land cover map was generated by classifying Landsat and ALOS PalSAR imagery (overall accuracy of 97%) to allow removing six common agricultural crops from estimates of tree cover. Finally, the GFC product was corrected through an integrated process using the nonlinear predictions of precipitation and elevation biases and the agricultural crop map as inputs. The accuracy of tree cover prediction increased by ≈29% over the original global forest change product (the R2 rose from 0.416 to 0.538). Using an optimized 89% tree cover threshold to create a forest/nonforest map, we found that fragmentation declined and core forest area and connectivity increased in the corrected forest cover map, especially in dry tropical forests, protected areas, and designated habitat corridors. By contrast, the core forest area decreased locally where agricultural fields were removed from estimates of natural tree cover. This research demonstrates a simple, transferable methodology to correct for observed biases in the Global Forest Change product. The use of uncorrected tree cover products may markedly over- or underestimate forest cover and fragmentation, especially in tropical regions with low precipitation, significant topography, and/or perennial agricultural production.

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