Within the framework of the research project SINDBAD (Seismic and Geoacoustic Investigations Along the Sunda-Banda Arc Transition) marine geophysical investigations have been carried out with RV SONNE from October 9th, 2006, to November 9th, 2006, off the eastern Sunda Arc and at the transition to the Banda Arc in Indonesia. The research cruise SO190 Leg 1 started in Jakarta, Indonesia and ended in Darwin, Australia. During this cruise, multichannel seismics (MCS), magnetics (M), and gravimetry (G) measurements have been carried out. Simultaneously, SIMRAD (multibeam echosounder) and PARASOUND (sediment echosounder) data have been collected using RV SONNEs onboard systems. During the expedition, a total of 4,933 km of profiles with MCS, M, and G have been acquired. Six of the 20 profiles are long overview profiles perpendicular to the deformation front and cover the entire forearc from the forearc basin across the outer arc high, the deformation front onto the oceanic lithosphere. Additional profiles have been acquired along strike in the Lombok forearc basin and in the Savu Basin. The main goal of the project SINDBAD is to investigate the relation between the variability of the lower plate and the tectonic evolution of the overriding plate (formation of an outer arc high, development of forearc basins, and accretion and erosion processes of the overriding plate). The "raw materials" – seafloor sediments, oceanic crust (at the Banda Arc also continental crust) and mantle lithosphere – are carried into the subduction system at the trench. The influence of these "raw materials" on the overriding plate is controlled by a number of factors: e.g. the convergence rate, the obliqueness of convergence and the physical and chemical properties of the lower plate (e.g. its age, its sediment-cover and –thickness, its fluid content and the composition of the crust). Forearc basins are today attracting increased attention because of their hydrocarbon potential. The forearc basins of the eastern Sunda Arc are still frontier areas which are almost unexplored. An additional goal of this project is therefore the assessment of the hydrocarbon potential of the Lombok Basin. In contrast to the Sumatra subduction zone, only a small amount of pelagic sediment is carried into the subduction system offshore East Java, Bali, Lombok, Sumbawa and Sumba. This results e.g. in a less pronounced development of the outer arc high, which is subaerial off Sumatra, but entirely below the sea surface in the eastern Sunda Arc. The Roo Rise, which is subducting off East Java, is a morphological high that lies about 1500 m higher than the Argo Abyssal Plain which is subducting further to the east. Despite of these pronounced differences, the deformation front in both areas shows similarities. While the foot of the slope shows lower dip than the upper slope, both areas are characterized by landward dipping thrust sheets. In both areas the outer arc high is characterized by active faults (the recent activity is indicated by deformed basin sediments on the outer arc high) and therefore no indications for a static backstop have been found. The accretionary character of the deformation front is clearly indicated in both areas, while subrosion in association with the subsidence of the Lombok Basin can not be excluded based on the preliminary interpretations. The trench in both areas is devoid of sediments, which indicates erosional processes caused by currents along the trench strike. However, a depocenter for these sediments could not be localized yet. While a forearc basin is not clearly developed off East Java, the Lombok forearc basin with water depths of more than 4000 m extends from off Bali to off Sumbawa. On the southern slope of the basin prograding sedimentary sequences indicate uplift, probably caused by the subducting Roo Rise or a growth of the outer arc high. Additionally, carbonate platforms on the acoustic basement indicate phases of rapid subsidence of the basin. The sediment thickness reaches a total of about 3.5 sec TWT. A few seismic "bright spots", but no bottom simulating reflectors (BSRs) have been identified in the basin. The profiles striking along the basin axis indicate paleo-depocenters in the western part of the profile, while the recent depocenter is located in the eastern part of the basin. On the northern flank of the Lombok basin, indications for submarine volcanism (recent activity is unknown) are indicated by a seamount reaching above the seafloor associated with a clear magnetic anomaly. East of the Lombok Basin the island of Sumba is located, which is regarded as a microcontinent that has been attached to the island arc during the Late Oligocene. Sumbas geographical location in front of the island arc is usually characterized by the location of a forearc basin and correlates with the seaward displacement of the deformation front (Roti Basin) at the transition from ocean/island arc subduction of the Sunda Arc to continent/island arc collision of the Banda Arc. An uplift of about 0.5 cm/a is reported for Sumba, associated with the underplating of the continental Scott Plateau. The uplift is especially evident in the MCS data. To the east of the Lombok Basin depocenter, a transition zone with deep reaching faults is observed, associated with eastward dipping sedimentary and basement structures. This transition zone is also indicated by anomalies in the magnetic and gravity data, the latter indicating isostatic undercompensation. On the western flank of Sumba, deformed sedimentary sequences indicate gravitational gliding in association with the uplift of Sumba. East of Sumba, two profiles into the Savu Basin have been acquired. Here the uplift of Sumba is indicated by the erosion of sedimentary sequences which have been deposited in the basin followed by uplift and subsequent erosion. Further indications of "inversion structures" are given by a reactivated thrust fault that in the past has served as the southern boundary of the Savu Basin und indicates recent activity by associated deformed basin sediments. The oceanic crust of the Argo Abyssal Plain and the Roo Rise is characterized by thin sediments. On a connection profile between two long profiles on the Argo Abyssal Plain a basin with about 1.4 sec TWT of sediment has been observed, that, indicated by a magnetic anomaly, can be correlated with an age jump of about 15 Ma, thereby indicating a paleo plate boundary.
During RV SONNE cruise 137 from 21st November to 28th December 1998 Geoscientific Investigations on the active Convergence Zone between the east Eurasian and Indo-Australian Plate (GINCO I) were carried out along the Sunda Arc, off Sumatra, Java and the Sunda Strait. The studies were headed by the BGR in close cooperation with German and Indonesian research institutions. A total amount of 5,500 km of magnetic, gravity and swath bathymetric profiles were recorded of which multi-channel seismic data exceeded 4,100 km. The scientific objectives were: (1) investigation of the structure and age of the accretionary wedges, outer arc highs and fore-arc basins off Sumatra and Java with special emphasis on the evolution of the Sunda Strait and the Krakatau area (2) differences in tectonic deformation between oblique (Sumatra) versus frontal (Java) subduction (3) search for oceanic crustal splinters in the accretionary wedges (4) definition of seismic sequences, thicknesses and ages of the fore-arc basin sediments as a pre-requisite for later on hydrocarbon assessments (5) identification and regional occurrence of bottom simulating reflectors (BSR) indicating gas hydrates. From the GINCO I project there is evidence for the existence of two accretionary wedges along the Sunda Arc: wedge I is of assumed Paleogene age and wedge II of Neogene to Recent age. The first inner wedge I is composed of tectonic flakes which are correlated from SE Sumatra across the southern Sunda Strait to NW Java. This implies a very similar plate tectonic regime at the time of the flake development during the Upper Oligocene to Lower Miocene and without marked differences in plate convergence direction from Java to Sumatra. Wedge I shows backthrusting along the northern transition toward the fore-arc basin. Today, wedge I forms the outer arc high and the backstop for the younger, outer wedge II. Magnetic, gravity and seismic results show, that within both wedges, there are no indications for an oceanic crustal splinter as hitherto postulated. Both wedges are underlain by oceanic crust of the subducting Indo-Australian slab which could be correlated from the trench off Sumatra up to 135 km to the northeast and up to 65 km from the trench off Java. Since the top of the oceanic crust differs considerably in reflectivity and surface relief we distinguished two types in the seismic records. One type is characterized by strong top reflections and a smooth surface and underlies accretionary wedge II and the southwest part of the wedge I (outer arc high) off Sumatra and Java. The second type has a low reflectivity and a rougher relief and underlies the tectonic flakes of accretionary wedge I (outer arc high) between the southwestern tip of Sumatra, the SundaStrait and NW Java. The missing outer arc high off the southern entrance of the Sunda Strait is explained by Neogene transtension in combination with arc-parallel strike-slip movements. The NW-SE running, transpressional Mentawai strike-slip fault zone (MFZ) was correlated from the SE Sumatra fore-arc basin to the NW Java fore-arc basin. Off the Sunda Strait northward bending branches of the MFZ are connected with the Sumatra Fault zone (SFZ). It is speculated that the SFZ originally was attached to the Cimandiri-Pelabuhan-Ratu strike-slip faults and shifted from the volcanic arc position into the fore-arc basin area due to clockwise rotation of Sumatra with respect to Java as well as due to increasingly oblique plate convergence since the late Lower Miocene. We explain the transtension of the western Sunda Strait (Semangka graben) and the transpression with inversion of the eastern Sunda Strait, along the newly detected Krakatau Basin, by this rotation. Seismostratigraphic interpretation revealed 5 main sequences (A - E), tentatively dated as Paleogene to Recent in age. The oldest seismic sequence A of assumed Eocene to Oligocene age is bounded at the top by a major erosional unconformity that was identified on all GINCO seismic profiles. The seaward diverging seismic pattern of sequence A is interpreted as a correlative sequence to the prograding Paleogene deltaic sediments encountered by wells offshore central and northern Sumatra. This is opposed to previous interpretation which assumed seaward dipping reflector sequences of basaltic origin erupted along the former Mesozoic passive margin of Sumatra. According to constructed time structure maps, the main NW-SE running depocentres of the post-Paleogene sediments are arc-parallel off Sumatra and Java with thicknesses of 3 s (TWT) and 5 s (TWT), respectively. The main depocentres of the Semangka graben and of the Krakatau Basin of the Sunda Strait strike north-south and have infills of 2 s - 5 s (TWT). Bottom simulating reflectors (BSR) occur within the upper sequences C - D along the flanks of the fore-arc basins and along doming structures but could not be detected in basin centres. Empiric relations of heat flow values and depths of BSR were determined indicating that with increasing waterdepth and decreasing heat flow the depths of the BSR increase.
Grenzwerte für Stickstoffdioxid vielerorts überschritten / Mehrere Episoden mit zu viel Feinstaub Die Luft in Deutschland war auch 2011 zu stark mit Feinstaub und Stickstoffdioxid belastet. Die Feinstaub-Werte lagen im Mittel über dem Niveau der vorangegangenen vier Jahre. Beim Stickstoffdioxid war die Belastung unverändert hoch. Das ergab eine erste Auswertung des Umweltbundesamtes (UBA) von vorläufigen Messdaten der Länder und des UBA. Vor allem in direkter Nähe zu Straßen werden in Städten und Ballungsräumen die Grenzwerte für Feinstaub und Stickstoffdioxid zu häufig überschritten. Beim Feinstaub lagen 42 Prozent der verkehrsnahen Stationen über dem zulässigen Tagesgrenzwert; dieser erlaubt nur 35 Tage mit über 50 Mikrogramm Feinstaub (PM10) pro Kubikmeter Luft (µg/m3) im Tagesmittel. Beim Stickstoffdioxid (NO2) lagen 57 Prozent der städtisch verkehrsnahen Stationen über dem erlaubten Jahresmittelwert von 40 µg/m3. UBA -Präsident Flasbarth rief dazu auf, bei der Luftreinhaltung nicht nachzulassen: „In großen Teilen Deutschlands hat die Luft eine gute Qualität. Allerdings müssen wir dort mehr tun, wo die Atemluft der Menschen immer noch mit zu viel Feinstaub und Stickstoffdioxid belastet ist: In den Städten und Ballungsräumen. Umweltzonen sind dafür ein geeignetes Mittel. Mit Einführung der modernsten Abgas-Norm (EURO 6) und der stetigen Durchdringung der Flotte mit solchen Fahrzeugen wird die Situation in Zukunft verbessert.“ Flasbarth wies darauf hin, dass Umweltzonen nur ein Teil der Lösung sind, da Feinstaub und Stickstoffoxide zu großem Teil auch bei Verbrennungsprozessen in Industrie und Haushalten entstehen. Emissionen aus der Landwirtschaft tragen ebenfalls zur Feinstaubbelastung bei. Erfolgreiche Luftreinhaltung funktioniere nur, wenn alle Sektoren einen Beitrag leisten: „Wir müssen ein Auge auf die Folgen der immer weiter dezentralisierten Energieerzeugung haben: Kleine Anlagen in Innenstädten dürfen nicht zu einer höheren Staubbelastung führen als die heutigen Großkraftwerke. Hier hat Deutschland mit der Verschärfung der Regelung für Kleinfeuerungsanlagen einen wichtigen Schritt gemacht.“, so Flasbarth. Ein weiterer Faktor, der sich vom Menschen nicht beeinflussen lässt, ist das Wetter : Bei austauscharmen Hochdruckwetterlagen wird die Luft viel weniger durchmischt. Das kann dazu führen, dass die Luft selbst dann schlechter wird, wenn die Emissionen der Autos, Heizungen oder Fabriken gleich bleiben. Im Jahr 2011 gab es gleich mehrere solcher austauscharmen Wetterlagen: Von Ende Januar bis März und im November führte dies zu häufigeren Überschreitungen des Feinstaub-Tagesgrenzwertes als in den Vorjahren. Ursache dieser Luftschadstoffbelastung bleiben jedoch die Emissionen, die es an der Quelle zu vermindern gilt. Das UBA wird die abschließende Bewertung der Luftqualität 2011 in Deutschland im ersten Halbjahr 2012 vorlegen, wenn die validierten und ergänzten Daten aus den Luftmessnetzen von Bund und Ländern ausgewertet sind. 06.02.2012
Die Stadt Stuttgart wird ab dem 11. Januar 2016 bei schadstoffträchtigen Wetterlagen den sogenannten Feinstaub-Alarm auslösen. Der Feinstaub-Alarm wird ausgelöst, sobald der Deutsche Wetterdienst an mindestens zwei aufeinanderfolgenden Tagen ein stark eingeschränktes Austauschvermögen der Atmosphäre prognostiziert (Inversionswetterlage). An diesen Tagen steigt die Konzentration der Luftschadstoffe wie Feinstaub und Stickstoffdioxid in Stuttgart stark an. Das Ministerium für Verkehr und Infrastruktur, das Regierungspräsidium und die Landeshauptstadt Stuttgart appellieren dann an die Bevölkerung in Stuttgart und in der Metropolregion, das Auto in der Umweltzone Stuttgart möglichst nicht zu nutzen und auf den Betrieb von so genannten „Komfort-Kaminen“ zu verzichten. Autofahrern wird empfohlen, möglichst auf die Verkehrsmittel des Umweltverbunds oder Fahrrad umzusteigen, zu Fuß zu gehen, Elektrofahrzeuge zu nutzen oder Fahrgemeinschaften zu bilden. Wenn möglich sollten Fahrten ganz vermieden werden. Die Bevölkerung wird u.a. über die städtischen Medien, Zeitungsannoncen, Verkehrsmeldungen, Vario-Tafeln an den innerstädtischen Ein- und Ausfahrtstraßen, Informationsanzeigen an der Autobahn und über die Website www.feinstaubalarm.stuttgart.de über den Beginn und das Ende des Feinstaub-Alarms informiert. Zwischen Auslösung des Feinstaub-Alarms am frühen Nachmittag und dem tatsächlichen Beginn liegt ein „Brückentag“, so dass die Bevölkerung rechtzeitig nach Mobilitätsalternativen suchen kann. Der Feinstaub-Alarm kann mehrere Tage lang andauern, mindestens aber zwei aufeinanderfolgende Tage. Zur Aufhebung des Feinstaub-Alarms muss der DWD eine nachhaltige und deutliche Verbesserung des Austauchvermögens prognostizieren, eine eintägige Unterbrechung der starken Einschränkung des Austauschvermögens reicht hierbei nicht aus. Für die Deutsche Umwelthilfe (DUH) geht der Appell, freiwillig aufs Auto zu verzichten und Bus oder Bahn zu fahren, nicht weit genug.