In this report, mineral composition of rock samples including conglomerate, sandstone, and dolomite was analyzed by IR spectral imaging using QDIP focal plane arrays (FPAs) with a peak-responsivity wavelength of 6.5 μm (FPA 1) and 5.5 μm (FPA 2). The qualitative and quantitative analyses are presented, and the key factor that determines the quantitative precision is discussed. In the qualitative analysis, the luminance of the different components in the rock samples was compared in the image. In the FPA 1 images, the shell fossil in the conglomerate sample and the limestone in the sandstone sample were darker than the other parts of the rocks due to their low emittance at 6.5 μm. In contrast, the difference in the luminance is hardly observed in the FPA 2 images under the same conditions. In the quantitative analysis, the emittance of dolomite was measured. Ten points in the IR image were randomly selected and the average emittance was calculated. The obtained emittances were 0.544±0.012 (FPA 1) and 0.941±0.019 (FPA 2), which means the coefficient of variation of the emittance measurement is ±2.1%~2.2%. By calculating the propagation of error, the precision of thermocouples for monitoring the temperature of the rocks in the calibration contributes most significantly (73%) to the total error.
The seismic hazard of Romania is relatively high, mainly due to the subcrustal earthquakes located at the sharp bend of the Southeast Carpathians, in Vrancea region, one of the most seismically active area in Europe. It is crossed by a series of principal and secondary faults. Vrancea area is assumed to be a conjunction of 4 tectonic blocks which lie on the edge of the Eurasian plate. Several GPS monitoring data revealed the motion of the blocks both in horizontal direction (relative motion of 5- 6 millimeters/year), as well as in vertical direction(of a few millimeters/ year).All data information available on the study area have been integrated in a unique database of geologic maps, thematic maps from cartography, land use maps provided by satellite images acquired in different spectral wavelengths by Landsat MSS, TM and ETM, SAR ERS and ASTER during a long term period (1975-2002). Satellite data are excellent for recognizing the continuity and regional relationships of faults . Synergy use of satellite data and image analysis techniques is essential for neotectonic applications, improving greatly the interpretability of the images and subsequent more accurate terrain features and lineament analysis of geologic structures in active seismic areas.
ASTER, launched in December, 1999, composed of three subsystems, each of which multispectrally observes the reflected or emitted radiation from the surface of the earth to space in VNIR (visible and near infrared), SWIR (shortwave infrared) and TIR (thermal infrared) wavelength regions, respectively. ASTER-VNIR has three spectral bands with a spatial resolution of 15m, and the one of which in near infrared has an along track stereo observation capability to produce high quality Digital Elevation Model (DEM). ASTER-SWIR has six spectral bands with a spatial resolution of 30m, which are mainly designed for discriminating altered minerals bearing hydroxyl group. ASTER-TIR has five spectral bands with a spatial resolution of 90m, which presents us a powerful tool for identifying quartz and carbonate minerals as well as discriminating types of silicate rocks. The author have successfully developed a robust method for detecting quartzite and carbonate rocks as well as classifying type of igneous rocks with ASTER TIR data without atmospheric corrections (Level-1B data). Here in this paper, reflectance spectra of minerals in SWIR region measured in the laboratory are analyzed to define calcite index, OH-bearing silicate index, kaolinite index and alunite index for discriminating each mineral by ASTER-SWIR. The defined indices are applied to SWIR data of ASTER Level-1B radiance at the sensor data observing Cuprite area in Nevada, USA, and the discussions are made on the results by comparing the well-known geology of the area. Also, the result of calcite index is compared with the result of applying well-characterized carbonate index defined for ASTER-TIR to clarify the strong point of each index.
ASTER sensor aboard NASA's Terra satellite has the capability of measuring multispectral thermal infrared (TIR) emission from the earth's surface to space. The author proposed indices by the combination of ASTER-TIR bands for detecting quartz and carbonate minerals, and another index to estimate the abundance of bulk SiO2 content in the surface silicate rocks, applied them to the low level ASTER radiance at the sensor data without atmospheric corrections, and showed a potential ability of the indices in a rock type mapping. This paper tries to apply the proposed method into the practical case studies using ASTER-TIR data. The study sites include ophiolitic belt zones in Oman and along Yarlun Zangbo River in Tibet. The applied results are compared with the geology of the study areas. It indicates that the new remote sensing approach proposed here would improve the quality and the cost of the geological mapping in arid and semi-arid regions.
ASTER sensor aboard Terra satellite has a capability of spectral measurement in the thermal infrared (TIR) region with a spatial resolution adequate for geological applications. This paper attempts mapping quarts, carbonate minerals and bulk SiO2 content in silicate rocks with the indices defined for ASTER TIR multispectral data. Silica minerals represented by the commonest mineral on earth, quartz, have a unique spectral property in TIR. They have lower emissivity in ASTER band 10 and band 12 spectral regions than in band 11. All the common carbonate minerals represented by calcite and dolomite have another unique spectral feature. They have low emissivity in ASTER band 14 spectral region, and high emissivity in ASTER band 10 to 13 spectral region. In silicate rocks, the wavelength at trough in TIR emissivity spectra systematically moves to longer wavelength as the rock type changes from felsic to ultramafic. The emissivity in band 12 is lower than in band 13 for felsic rocks, and higher for ultramafic rocks. Using the spectral features described above, several indices are defined. They are applied to ASTER Level 1B data in the study areas. The results are compared with the information from the field and the laboratory geological investigations including the TIR spectra of the rocks collected at the site and published geological maps. Potential ability of the indices in mapping quarts, carbonate minerals and silicate rocks is suggested.
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