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<p>The potential of variations of <i>b-</i>values in the G-R relation, log<i>N=a-bM</i> as earthquake precursors for small events (rockbursts) in Zinkgruvan mine, Sweden and for tectonic (large) earthquakes in the Andaman-Sumatra region were investigated. </p><p>The temporal frequency-magnitude distribution, <i>b(t)</i>, of rockbursts in Zinkgruvan mine was examined using high quality data recorded during the period November 1996 to April 2004 with magnitude ranges from <i>M</i><i>w</i>= -2.4 to 2.6. A sliding time-window was applied to compute <i>b</i>-values. The windows contain 50 events and were shifted with steps of 5 events. The results indicated that <i>b</i>-values significantly drop preceding rockbursts of magnitude <i>M</i><i>w</i>≥1.6.</p><p>Temporal and spatial variations of <i>b</i>-values were also examined for tectonic earthquakes, magnitude <i>M</i><i>w</i>≥4.1, in the Andaman-Sumatra region. Earthquake data from the ISC, IDC, NEIC and HVRD earthquake catalogs for a period from 01/01/1995 to 12/26/2004 were used for analysis. Spatial variations of <i>b</i> were calculated from circular areas containing 50 events, with nodes on a 0.5° x 0.5° grid. The analysis shows that <i>b(t)</i> estimates using data from different catalogs<i> </i>are comparable and that large earthquakes are preceded by a drop in <i>b(t)</i> of about 0.3~1. The distribution of stress deduced from <i>b</i>-value mapping shows that large earthquakes occurred in the high stress, i.e. low <i>b</i>-value, areas.</p><p>Aftershock sequences of the <i>M</i><i>w</i>=9, December 26, 2004 and the <i>M</i><i>w</i>=8.7, March 28, 2005 shocks were investigated by using the same methods. Results from aftershock sequences show similar behaviour as for the large and presumed independent main events.</p><p>The observed variations of <i>b</i>-values with time and in space support the hypothesis that <i>b</i>-values have a precursory potential. The method can be used for a wide range of earthquake magnitude, from microearthquakes (<i>M</i><i>w</i><3) to giant tectonic shocks (<i>M</i><i>w</i>~9) and for both of independent shocks and aftershocks.</p>

The potential of variations of b-values in the G-R relation, logN=a-bM as earthquake precursors for small events (rockbursts) in Zinkgruvan mine, Sweden and for tectonic (large) earthquakes in the Andaman-Sumatra region were investigated. The temporal frequency-magnitude distribution, b(t), of rockbursts in Zinkgruvan mine was examined using high quality data recorded during the period November 1996 to April 2004 with magnitude ranges from Mw= -2.4 to 2.6. A sliding time-window was applied to compute b-values. The windows contain 50 events and were shifted with steps of 5 events. The results indicated that b-values significantly drop preceding rockbursts of magnitude Mw≥1.6. Temporal and spatial variations of b-values were also examined for tectonic earthquakes, magnitude Mw≥4.1, in the Andaman-Sumatra region. Earthquake data from the ISC, IDC, NEIC and HVRD earthquake catalogs for a period from 01/01/1995 to 12/26/2004 were used for analysis. Spatial variations of b were calculated from circular areas containing 50 events, with nodes on a 0.5° x 0.5° grid. The analysis shows that b(t) estimates using data from different catalogs are comparable and that large earthquakes are preceded by a drop in b(t) of about 0.3~1. The distribution of stress deduced from b-value mapping shows that large earthquakes occurred in the high stress, i.e. low b-value, areas. Aftershock sequences of the Mw=9, December 26, 2004 and the Mw=8.7, March 28, 2005 shocks were investigated by using the same methods. Results from aftershock sequences show similar behaviour as for the large and presumed independent main events. The observed variations of b-values with time and in space support the hypothesis that b-values have a precursory potential. The method can be used for a wide range of earthquake magnitude, from microearthquakes (Mw&lt;3) to giant tectonic shocks (Mw~9) and for both of independent shocks and aftershocks.

We report on a small collection of parachuting frogs from Sumatra and Java. Three new species are described. Rhacophorus achantharrhena is similar to R. dulitensis and R. prominanus and differs from these species by a suite of characters including morphology of the supratympanic fold, digital webbing, coloration, and morphometrics. These three species are unusual in having white visceral and parietal peritonea. Rhacophorus catamitus is a small species similar to R. angulirostris and differing from this species by having a calcar at the heel and reduced digital webbing. Rhacophorus barisani resembles R. baluensis but differs from this species in color pattern, habitus, webbing of the fingers, and morphology of the dermal appendages. A new specimen of Sumatran R. pardalis is described and compared to the holotype of R. pulchellus. Rhacophorus prominanus is reported from Gunung Rajabasa, Lampung. Two specimens are described and compared to Bornean R. dulitensis and R. prominanus from the Malay Peninsula. Rhacophorus tunkui Kiew is a junior subjective synonym of Rhacophorus prominanus Smith. Finally, we describe new specimens of Rhacophorus margaritifer from Cibodas, Java, Skeletons of the new species and of R. margaritifer are described in detail. Superficial jaw and throat musculature appears to be relatively conservative within the genus.

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Nous modélisons le rapport entre variation de pesanteur et déplacement vertical du sol dus à une surcharge à la surface d'un modèle de Terre à symétrie sphérique, stratifié et élastique. Les résultats théoriques sont comparés aux valeurs numériques trouvées pour diverses charges à partir des sorties de modèles globaux. Nous évaluons la résolution et la précision des variations temporelles du contenu en eau du sol estimées par la mission de gravimétrie spatiale GRACE. Celles-ci sont comparées aux prédictions des variations saisonnières de plusieurs modèles hydrologiques. En Europe, la validation des mesures GRACE par les mesures des gravimètres du reseau GGP repose sur une analyse en composantes principales et met en évidence la sécheresse de l'été 2003. Les signatures gravitationnelles cosismique et postsismique associées au séisme de Sumatra (2004) sont extraites des données GRACE. Une modélisation de l'effet cosismique montre que la réponse statique de l'océan ne peut être negligée.

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This thesis deals with the selected issues regarding tropical rainforests in modern civilization. It explains what the tropical rainforest is and where it is located. The thesis points at the importance of the tropical rain forestry, and warns of increasing threats primarily due to deforestation. The thesis also shows possible approaches to deal with the issue and presents a practical example of a functional project in real life.

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