Volcanic ash observation in active volcano areas using teleoperated mobile robots - Introduction to our robotic-volcano-observation project and field experiments

2013 ◽  
Author(s):  
Keiji Nagatani ◽  
Ken Akiyama ◽  
Genki Yamauchi ◽  
Hikaru Otsuka ◽  
Takuma Nakamura ◽  
...  
Keyword(s):  
Mobile Robots ◽  
Volcanic Ash ◽  
Field Experiments ◽  
Active Volcano

In situ study of volcanic ash resuspension using a portable wind tunnel.

2020 ◽  
Author(s):  
Jacopo Taddeucci ◽  
Elisabetta del Bello ◽  
Jonathan P Merrison ◽  
Keld R Rasmussen ◽  
Jens J Iversen ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
High Speed ◽  
Volcanic Ash ◽  
Field Experiments ◽  
Critical Parameters ◽  
Test Bed ◽  
High Definition ◽  
Sustained Activity

<p>The resuspension of volcanic ash deposits by wind is a well-known source of hazard following explosive eruptions. Besides the mail control exerted by the local wind field, ash resuspension is also influenced by: 1) atmospheric humidity; 2) features of the deposit (grain size distribution, sedimentary structures, etc.), and 3) features of the substrate (i.e. moisture, roughness). Ash resuspension is modeled using numerical simulations, which however require physical characterization and identification of the critical parameters controlling ash resuspension. Wind tunnel studies on volcanic particles are very limited and restricted to laboratory parameterizations, with in-situ effects not been parameterized. We tested field experiments of volcanic ash resuspension developing a portable wind tunnel and deploying on proximal (3 km) ash deposits from the semi-sustained activity of Sakurajima volcano (Japan) and from distal (250 km ca.) ash deposits from the 2011 Cordon Caulle eruption (Chile). The wind tunnel is calibrated with both LDA and pitot tubes measurements. The device allows generating a controlled wind profile within a 110x12x12 cm test section, which is placed directly on an untouched test bed of naturally deposited ash. Two types of experiments were performed: 1) ramp up speed experiments, where the wind speed is increased until reaching the threshold friction speed on four different substrates; 2) constant speed experiments, where three wind speed values where kept for 20 minutes using the same substrate. The threshold friction speed is measured with a hot wire anemometer, and the movement of resuspended ash is detected by means of multiple high speed and high definition digital camcorders. In-situ measured threshold friction speeds are compared to 1) in situ observed episodes of resuspension driven by local winds and 2) laboratory determination of threshold friction speed in controlled environmental conditions, and using the same ash deposited homogeneously.</p><p> </p>

scholarly journals Analysis of Japanese Volcanic Ash Dispersion on the Korean Peninsula using Satellite Imagery

2020 ◽  
Vol 20 (3) ◽  
pp. 269-275
Author(s):  
Jongsun Sun ◽  
Jae-kwang Ahn ◽  
Haseong Lee ◽  
Eui-Hong Hwang ◽  
Duk Kee Lee
Keyword(s):  
Korean Peninsula ◽  
Volcanic Eruption ◽  
Volcanic Ash ◽  
Satellite Images ◽  
Volcanic Eruptions ◽  
Active Volcano ◽  
Accurate Information ◽  
Secondary Damage ◽  
Hypothetical Scenario ◽  
Ash Dispersion

A volcanic eruption is a kind of global natural disaster that can occur suddenly and cause great damage to humankind. During the eruption, the magma causes fatal damage to life and property in areas near the volcano, and nearby countries are affected by the spread of volcanic ash, causing secondary damage due to air and soil pollution. Near the Korean peninsula, there exists an active volcano that can spread volcanic ash over long distances by erupting above Volcanic Explosivity Index (VEI) 4. Volcanoes in Japan have been known to cause considerable volcanic ash damage on the Korean Peninsula during eruption. Accordingly, the Korea Meteorological Administration is developing technology to predict and monitor volcanic ash spread using satellite images. However, despite the fact that empirical models for volcanic ash diffusion range prediction are used during volcanic eruptions, continuous improvement is needed for accurate information prediction. In this study, satellite images were analyzed not for the predicted distance of volcanic ash clouds, but for the actual distance of volcanic ash dispersion in cases where the volcanic ashes dispersed in the direction of the Korean peninsula. Of the 3,880 volcanoes that erupted in Japan over the last four years, 111 cases were identified where the height and spread distance of the volcanic ash that erupted toward the Korean Peninsula can be confirmed. In addition, the actual volcanic eruption cases and modeling results were analyzed to determine the extent of volcanic ash spread, and a hypothetical scenario was tested to quantify the direct damage of the volcanic ash. From the analysis of the volcanic ash spread through the virtual simulations, it was found that the height of the volcanic ash, the direction of the wind, and wind speed during volcanic eruption were important factors.

scholarly journals Element Content in Volcano Ash, Soil and River Sediments of the Watershed in the Volcanic Area of South Iceland and Assessment of Their Mobility Potential

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1928
Author(s):  
Dragana Đorđević ◽  
Sanja Sakan ◽  
Snežana Trifunović ◽  
Sandra Škrivanj ◽  
David Finger
Keyword(s):  
Volcanic Ash ◽  
River Sediments ◽  
Active Volcano ◽  
Transport Processes ◽  
Element Content ◽  
Volcanic Area ◽  
Natural Catastrophes ◽  
Chemical Fingerprints ◽  
Mobile Phases ◽  
Wind And Water Erosion

In this work, we present the results of element content in river sediments and soil of the Rangárvellir river in southern Iceland as well as in the volcano ash from the Eyjafjallajökull eruption in 2010. Severe natural catastrophes have devastating impact on the environment. We selected the Rangárvellir area located in the vicinity of Mt Hekla, Iceland’s most active volcano, for our study. This study site is ideal to investigate wind and water erosion and sediment transport processes of two main glaciers rivers: the Eystri-Rangá and the Ytri-Rangá and the Hroarslækur River. Sediments of these rivers consist of volcano materials, ash and lava. In order to assess the sediment dynamics, we collected sediment, soil and volcanic ash. The fractioning of the elements was carried out using sequential extractions. The distribution of Si indicates that the sediments originate from the same geochemical basis. Li and partly B exist in the first phase of volcanic ash and river sediments but not in the mobile phases of soils. In the mobile phase of volcanic ash, P was found but it did not exist in the first phase of soil and sediments. These results suggest the different chemical fingerprints in the water sediments and surrounding soil.

Fusion and TBC Penetration Characteristics of Volcanic Ash Collected from Active Volcano

2020 ◽  
Vol 29 (4) ◽  
pp. 582-596
Author(s):  
Yuta Fukushima ◽  
Masayuki Arai ◽  
Kiyohiro Ito ◽  
Tatsuo Suidzu
Keyword(s):  
Volcanic Ash ◽  
Active Volcano

3D traversability awareness for rough terrain mobile robots

Sensor Review ◽  
2014 ◽  
Vol 34 (2) ◽  
pp. 220-232 ◽  
Author(s):  
Giulio Reina ◽  
Mauro Bellone ◽  
Luigi Spedicato ◽  
Nicola Ivan Giannoccaro
Keyword(s):  
Mobile Robots ◽  
Field Experiments ◽  
Point Clouds ◽  
Unmanned Vehicles ◽  
Outdoor Environment ◽  
Local Descriptor ◽  
Content Type ◽  
3D Point Clouds ◽  
Outdoor Environments ◽  
Indoor And Outdoor

Purpose – This research aims to address the issue of safe navigation for autonomous vehicles in highly challenging outdoor environments. Indeed, robust navigation of autonomous mobile robots over long distances requires advanced perception means for terrain traversability assessment. Design/methodology/approach – The use of visual systems may represent an efficient solution. This paper discusses recent findings in terrain traversability analysis from RGB-D images. In this context, the concept of point as described only by its Cartesian coordinates is reinterpreted in terms of local description. As a result, a novel descriptor for inferring the traversability of a terrain through its 3D representation, referred to as the unevenness point descriptor (UPD), is conceived. This descriptor features robustness and simplicity. Findings – The UPD-based algorithm shows robust terrain perception capabilities in both indoor and outdoor environment. The algorithm is able to detect obstacles and terrain irregularities. The system performance is validated in field experiments in both indoor and outdoor environments. Research limitations/implications – The UPD enhances the interpretation of 3D scene to improve the ambient awareness of unmanned vehicles. The larger implications of this method reside in its applicability for path planning purposes. Originality/value – This paper describes a visual algorithm for traversability assessment based on normal vectors analysis. The algorithm is simple and efficient providing fast real-time implementation, since the UPD does not require any data processing or previously generated digital elevation map to classify the scene. Moreover, it defines a local descriptor, which can be of general value for segmentation purposes of 3D point clouds and allows the underlining geometric pattern associated with each single 3D point to be fully captured and difficult scenarios to be correctly handled.

Burn lessons learned from the Whakaari White Island volcanic eruption

2021 ◽  
Author(s):  
Paul Baker ◽  
Michelle Locke ◽  
Amber Moazzam ◽  
Matthew Taylor ◽  
Francois Stapelberg ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Total Body Surface Area ◽  
Skin Grafting ◽  
Active Volcano ◽  
Lessons Learned ◽  
Protective Equipment ◽  
Total Body ◽  
Burn Depth ◽  
White Island ◽  
Ballistic Trauma

Abstract New Zealand's most active volcano, Whakaari White Island was a common tourist attraction prior to its eruption on 9 th December 2019. At the time of the eruption, there were 47 people on the island from three tour groups. 39 people survived the initial eruption and were extracted. 31 entered into the New Zealand National Burn Service across four hospitals. The median age of the patients treated at the National Burn Centre was 45.5 years (range: 14 − 67 years) and median total body surface area burn was 49.5% (range: 9% - 90%). The three month survival of this eruptive event was 55%, which subsequently fell to an overall rate of 53% following one late death of an early survivor after repatriation home. Of the patients who survived the initial eruption for long enough to be admitted to the National Burn Service, the overall survival rate was 71% at three months. We describe 12 lessons we have learnt from our management of the survivors. The key surgical lessons among these are: The injuring mechanism combined ballistic trauma, thermal and acidic burn components, with the acid component being the most problematic and urgent for management. Volcanic ash burns result in on-going burn depth progression, deep underlying tissue damage and significant metabolic instability. Early skin grafting was not successful in many cases. Reconstructive strategy needed adjusting to cope with the high operative demand and limited donor sites in all patients. Protect yourself from potential dangers with additional personal protective equipment (PPE) in an unfamiliar setting.

Development and field test of teleoperated mobile robots for active volcano observation

2014 ◽  
Author(s):  
Keiji Nagatani ◽  
Ken Akiyama ◽  
Genki Yamauchi ◽  
Kazuya Yoshida ◽  
Yasushi Hada ◽  
...  
Keyword(s):  
Mobile Robots ◽  
Field Test ◽  
Active Volcano

Electron Microscopy of the Shape of Small Metal Particles

1977 ◽  
Vol 35 ◽  
pp. 300-301
Author(s):  
M. Jose Yacaman
Keyword(s):  
Electron Microscopy ◽  
Metal Particle ◽  
Field Experiments ◽  
Size Range ◽  
Dark Field ◽  
Metal Particles ◽  
Bragg Condition ◽  
Crystal Particle ◽  
Small Metal Particle ◽  
Small Metal Particles

In the Study of small metal particles the shape is a very Important parameter. Using electron microscopy Ino and Owaga(l) have studied the shape of twinned particles of gold. In that work electron diffraction and contrast (dark field) experiments were used to produce models of a crystal particle. In this work we report a method which can give direct information about the shape of an small metal particle in the amstrong- size range with high resolution. The diffraction pattern of a sample containing small metal particles contains in general several systematic and non- systematic reflections and a two-beam condition can not be used in practice. However a N-beam condition produces a reduced extinction distance. On the other hand if a beam is out of the bragg condition the effective extinction distance is even more reduced.

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