scholarly journals Automatic Mapping of the Lava Flows at Piton de la Fournaise Volcano, by Combining Thermal Data in Near and Visible Infrared

10.5772/37685 ◽  
2012 ◽  
Author(s):  
Z. Servadio ◽  
N. Villeneuve ◽  
P. Bachlery
Keyword(s):  
Lava Flows ◽  
Piton De La Fournaise ◽  
Thermal Data ◽  
Automatic Mapping

scholarly journals AUTOMATIC MAPPING OF GLACIER BASED ON SAR IMAGERY BY BENEFITS OF FREELY OPTICAL AND THERMAL DATA

2015 ◽  
Vol XL-3/W2 ◽  
pp. 47-51
Author(s):  
L. Fang ◽  
L. Hoegner ◽  
U. Stilla
Keyword(s):  
Land Surface ◽  
Low Resolution ◽  
Glacier Surface ◽  
Thermal Data ◽  
Automatic Mapping ◽  
Resources Evaluation ◽  
Sar Imagery ◽  
Normalized Difference Snow Index ◽  
Occurrence Matrix

For many research applications like water resources evaluation, determination of glacier specific changes, and for calculation of the past and future contribution of glaciers to sea-level change, parameters about the size and spatial distribution of glaciers is crucial. In this paper, an automatic method for determination of glacier surface area using single track high resolution TerraSAR-X imagery by benefits of low resolution optical and thermal data is presented. Based on the normalized difference snow index (NDSI) and land surface temperature (LST) map generated from optical and thermal data combined with a surface slope data, a low resolution binary mask was derived used for the supervised classification of glacier using SAR imagery. Then, a set of suitable features is derived from the SAR intensity image, such as the texture information generated based on the gray level co-occurrence matrix (GLCM), and the intensity values. With these features, the glacier surface is discriminated from the background by Random Forests (RF) method.

scholarly journals Advanced NDT Methods and Data Processing on Industrial CFRP Components

2019 ◽  
Vol 9 (3) ◽  
pp. 393 ◽  
Author(s):  
Vito Dattoma ◽  
Francesco Panella ◽  
Alessandra Pirinu ◽  
Andrea Saponaro
Keyword(s):  
Data Processing ◽  
Defect Detection ◽  
Temperature Response ◽  
Computation Method ◽  
Impact Simulation ◽  
Thermal Data ◽  
Surface Defect Detection ◽  
Automatic Mapping ◽  
Nondestructive Investigation ◽  
Thermal Pulses

In this work, enhanced thermal data processing is developed with experimental procedures, improving visualization algorithm for sub-surface defect detection on industrial composites. These materials are prone to successful infrared nondestructive investigation analyses, since defects are easily characterized by temperature response under thermal pulses with reliable results. Better defect characterization is achieved analyzing data with refined processing and experimental procedures, providing detailed contrasts maps where defects are better distinguished. Thermal data are analyzed for different CFRP specimens with artificial defects and experimental procedures are verified on real structural aeronautical component with internal anomalies due to impact simulation. A better computation method is found to be useful for simultaneous defect detection by means of automatic mapping of absolute contrast, optimized to identify defect boundaries.

Measuring effusion rates of obsidian lava flows by means of satellite thermal data

2017 ◽  
Vol 347 ◽  
pp. 82-90 ◽  
Author(s):  
D. Coppola ◽  
M. Laiolo ◽  
A. Franchi ◽  
F. Massimetti ◽  
C. Cigolini ◽  
...  
Keyword(s):  
Lava Flows ◽  
Thermal Data ◽  
Effusion Rates

Genese du champ de lave de l'Enclos Fouque; une eruption d'envergure exceptionnelle du Piton de la Fournaise (Reunion) au 18 e siecle

2001 ◽  
Vol 172 (2) ◽  
pp. 177-188 ◽  
Author(s):  
Jean-Francois Lenat ◽  
Patrick Bachelery ◽  
Frederic Desmulier
Keyword(s):  
Satellite Images ◽  
18Th Century ◽  
Lava Lake ◽  
Summit Crater ◽  
Lava Flows ◽  
Chemical Compositions ◽  
Piton De La Fournaise ◽  
North West ◽  
The North ◽  
The Future

Abstract A large lava flow field, essentially constituted of "pahoehoe" flows, forms a relatively monotonous area on the north-west flank of the terminal cone of Piton de la Fournaise and on a large part of the Enclos floor. We named this unit "champ de lave de l'Enclos Fouque" (CLEF). To the east, more recent lava flows almost completely cover the CLEF. Mapping of the CLEF has been attempted using satellite imagery. Radar (SIR-C) and SPOT images have been used. Both types of images lead to comparable results for the surface of the CLEF, estimated to 11 km 2 . On satellite images, only a general map of the facies of the CLEF can be done. Air photos and ground observations allow to characterize more precisely the facies defined from satellite images. On the slopes of the Central Cone, the surface of the CLEF is mostly composed of tumuli that may produce small lava flows at their downhill base. On the floor of the Enclos, the CLEF is constantly formed by a multitude of intricate small flows. Except for small "aa" patches, surfaces are "pahoehoe". Tumuli, pressure ridges and collapsed plates are common features of the CLEF. Near the NW border of Enclos, the surface becomes less regular, with a higher proportion of "aa" patches and tilted slabs. This is probably due to the increase of slope in this area. In the vicinity of Bory crater contemporaneous welded scoria cover a zone extending 150-200 m from the crater. Several elements, found in various historical documents collected by Lacroix [1936 and 1938], bring evidence that the CLEF may result from a succession of events between the years 1750's to the 1790's. During this period, the volcano has been virtually continuously in eruption. Bory crater was the only active crater until 1766, when a new summit crater was formed by collapse, 400 m east of Bory crater. In the following years, this 1766 crater was filled by lava emissions which erected a gigantic tumulus, 50 m high, called Mamelon central. Several large lava flows, some of them reaching the sea, are unambiguously described as emitted from the summit craters. One of the main event appears to be the phase that occurred in 1753 (or 1759 according to different authors). This phase was associated to felt earthquakes and widespread ash-falls in the island. Lava flows covered most the western part of Enclos and reached the sea to the east. Whereas the activity of 1753 (1759 ?) appears as paroxysmal, extensive lava flows are described until 1794. In 1791, a new crater formed south of the 1766 crater. In 1801, Bory de St-Vincent [1804] observed an active lava lake inside this 1791 crater. In summary, it appears that quasi-continuous activity took place during the second half of the 18th century at Piton de la Fournaise, with lava flows covering almost all the Enclos and Grand Brule areas. It is obvious that the presently outcropping surface of the CLEF is only a fraction of its former extension. From the above-mentioned historic descriptions, it is reasonable to assume the CLEF may have recovered the entire surface of the Enclos Fouque and the Grand Brule depression. The surface extension of the CLEF would thus lie between 11 km 2 , its presently observed area, to ca. 90 km 2 . The compounded thickness of the CLEF has not been directly observed. In the rim of Dolomieu crater, a series of lava flows thought to represent the CLEF is about 25 m thick, but this thickness is that of the shield built around the vents and not that of the lava field. Using statistical laws for strombolian cones morphometry from Wood [1980], the thickness of the CLEF may be approached considering the crater diameter of 3 cones located in the north-western part of Enclos and partially flooded by the CLEF. We obtain estimates of 5 to 15 m. If Enclos has been entirely covered by the CLEF and for a mean thickness of 5 to 10 m, then the volume of the CLEF eruption is 450 to 900X10 6 m 3 . Mineralogical and chemical compositions of the CLEF lavas are similar to those of the transitional olivine basalts of the historic period [steady-state basalts, Albarede et al, 1997]. The chemical compositions vary somewhat due to variable modal olivine phenocrysts abundances and are characteristic of a rapid transfer of magma from deep reservoirs with virtually no low-pressure evolution. Major changes of the summit craters were associated to this eruption as a result of the unusually prolonged magmatic activity at Piton de la Fournaise during decades. The occurrence of similar phases at Piton de la Fournaise in the future can be appraised with reference to Kilauea. Holcomb [1987] reports 7 long-lived eruptions at Kilauea in the last 3 centuries. Thus, although not frequent, this type of event is not uncommon for Kilauea. By analogy, it must be considered as probable that Piton de la Fournaise will experience new long-lived eruptions in the future.

scholarly journals CONCEPTUAL FRAMEWORK OF COMBINED PIXEL AND OBJECT-BASED METHOD FOR DELINEATION OF DEBRIS-COVERED GLACIERS

2018 ◽  
Vol IV-5 ◽  
pp. 173-180 ◽  
Author(s):  
R. Sahu ◽  
R. D. Gupta
Keyword(s):  
High Spatial Resolution ◽  
Remote Sensing Data ◽  
Optical Data ◽  
New Approach ◽  
Shadow Area ◽  
Object Based ◽  
Thermal Data ◽  
Automatic Mapping ◽  
Glacier Mapping ◽  
Manual Correction

<p><strong>Abstract.</strong> Delineation of the glacier is an important task for understanding response of glaciers to climate. In Himalayan region, most of the glaciers are covered with debris. Supraglacial debris works as an obstacle for automatic mapping of glacier using remote sensing data. Different methods have been used to reduce this difficulty based on pixel-based and object-based approaches using optical data, thermal data and DEM. Pixel-based glacier mapping is a traditional method for delineation of the glacier but the object-based method has emerged as a new approach in cryosphere application leading to its successful application in different applications. All pixel-based methods require some degree of manual correction because these can’t be delineated automatically, especially in shadow area and debris covered part of the glacier. In the majority of studies, the object-based method has provided higher accuracy to delineate the debris-covered glacier. Spatially high spatial resolution satellite data is best suited for object-based image classification. In future, a combination of pixel-based method and object-based method can be attempted for delineation of the debris-covered glacier along with its critical analysis for suitability. The present paper critically reviews pixel-based and object-based methods as well as provides a framework for combined pixel and object-based method for delineation of debris-covered glacier.</p>

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