ANdean COntinental Research Project
The aim of the project was to yield an image of the subduction process of the Nazca plate underneath South America. To obtain information about the velocity too, a combined near-vertical, wide-angle reflection/refraction seismic investigation was carried out. The profile stretched W-E at 21°S for 370 km from the coast of the Pacific ocean (Chile) until the Altiplano in Bolivia.
The interpretation of seismic refraction/wide-angle reflection data from the 1995 Crustal Investigations off- and on-shore Nazca/Central Andes (CINCA95) project has resulted in the derivation of nine E-W two-dimensional (2-D) velocity cross sections for the region between the Peru-Chile trench and the coast between 19.5°S and 25°S, with three of the cross sections extending a farther 100-200 km inland. These sections define the major lithospheric structures of the upper South American plate and the lower Nazca plate down to uppermost mantle depths of 30-60 km beneath this part of the present-day forearc region. In addition to showing the Nazca plate subducting at an increasing angle of 9-25° down to 30-50 km depth near the coast, these cross sections show a portion of the Moho dipping eastward from 43-50 km near the coast to 55-64 km up to about 240 km inland.
The goal of this project is to image the Cape Verde mantle plume with seismological methods and to determine the physical properties of the plume.
The Dabie Shan marks the collision zone between the Sino-korean and the Yangtze craton with exposed ultra-high pressure metamorphic complexes. This region was considered as a possible drill site in the framework of the ICDP project. In spring 1997 a joint Chinese-German seismic project was carried out to investigate this region. The main objective of this project was to reveal the structure of the Earth's crust down to the Moho to understand the processes which are connected with the process of the triassic collision.
DEad SEa Rift Transect
A multi-national and interdisciplinary project to study the crustal structure and geodynamics of the Dead Sea Transform.
GEO-DESIRE aims at studying the corner-stone of the geo-dynamics of the region, the pull-apart basin – the Dead Sea Basin. DESIRE will build on the knowledge from previous geoscientific/geophysical experiments like DESERT and the existing GPS and seismological networks in the Middle East.
Records of densely spaced shots along the Sino-US reflection line INDEPTH II at offsets between 70 and 130 km parallel to the main profile provide an image of the crust straddling the Indus-Yarlung suture. The major features are prominent reflections at about 20 km depth beneath and extending out to about 20-30 km north and south of the surface exposure of the suture, and north-dipping reflectors north of the suture. Despite the fact that several geological interpretations for the reflections are possible, the seismic mapping points to the importance of post-collisional (Oligocene-Miocene) tectonics, which reshaped the suture.
In the summer of 1998 as part of the INDEPTH III project, wide-angle seismic data were recorded from large shots along a 400 km long NNE-SSW profile crossing the Banggong-Nujiang suture (BNS) at about 89.5°E in central Tibet. Analysis of these data suggests that i) crustal thickness in the vicinity of the Banggong-Nujiang suture is 65+/-5 km and there is no evidence at 89.5°E for a step of 20 km in the Moho at the BNS and ii) a 25-30 km thick high velocity (6.5-7.2 km/s) lower crustal layer exists. In addition the present P-wave model contains no crustal low velocity layer.
The goal of the project GRANU 95 was an seismic investigation of the Saxothutingian zone of the Variscian foldbelt. A special focus was the saxonian Granulitgebirge and the question of its origin. Another adressed problem was the SW extension of the Saxothuringian zone and its relationship to the Muenchberger Gneissmasse.
Monitoring of microseismicity due to fluid injection
The project aims to investigate the possibility of monitoring microseismicity due to fluid injection in sedimentary rocks. The drill hole which is used for the frac-experiment is situated in Gross Schoenebeck, 45 km north of Berlin.
Hawaii Plume Project
Hawaii is certainly one of the best known examples of regions associated to hotspot-volcanism. The Hawaii-Emperor chain was formed by hot material ascending from the earth's deep interior. While the position of the plume conduit is approximately fixed the Pacific plate slowly passes over it, leaving behind a chain of volcanic islands.
In a previous study Li et al. (2000) investigated broadband data from station KIP (Oahu) and a temporary array (HIBSN) on the Big Island. The basic findings are an updoming area of the 660 km discontinuity SW of Big Island and a low velocity zone (LVZ) in about 140 km depth beneath the SW of Big Island.
The project I-GET is aimed at developing an innovative geothermal exploration approach based on advanced geophysical methods. The objective is to improve the detection, prior to drilling, of fluid bearing zones in naturally and/or artificially fractured geothermal reservoirs. This new approach will be tested in four European geothermal systems with different geological and thermodynamic reservoir characteristics.
Lake Toba (Sumatra)
Determination of crustal velocity structure around Lake Toba (incl. Sumatra Fault) and possibly between Nias Island and the coast using British air-gun sources (Pg and Pn phases). Using local volcano-related events to study Lake Toba caldera and its relation to Sumatra Fault.
In the early winter/spring of 2002, a scientific drilling program was carried out in the Mackenzie Delta, NW territories, Canada. The main objective is to investigate permafrost gas hydrates in one of the most prominent occurences of its kind.
The aim of the magnetotelluric part of the MERAPI project is to test the magnetotelluric method for its ability to obtain information about the electrical conductivity structure of the volcano and to monitor volcanic activity by recording electric and magnetic field variations.
The aim of this project is to investigate the transition zone between the SE Atlantic and the African continent to reveal the history and mechanisms of the break-up and its relation to the driving magmatic processes. To achieve this goal GFZ (Potsdam), BGR(Hannover) and the CGS (Cape Town) will conduct together a seismic onshore-offshore wideangle experiment between about 30° and 32° S latitude.
SAFOD is the San Andreas Fault Observatory at Depth. The goal of SAFOD is to provide direct observational data on the composition, physical state and mechanical behavior of a major active fault zone at depth to test hypotheses pertaining to faulting and earthquake generation.
The Seychelles Plateau is believed to be continental material isolated during the separation of Africa from India some 60 million years ago. A 10 month deployment of broad-band and short-period 3-component seismometers started February 2003 with the aim of studying the heterogeneity and anisotropy of the upper-mantle beneath the Seychelles. Questions to be addressed are the role of the Seychelles during breakup, evidence of subsequent plume activity and the extent to which the plateau is continental in nature.
In November 2001 a network of reflection profiles utilizing airgun sources was shot using the RV Sonne across the continental margin of southern Chile, in the vicinity of the source region of the 1960 earthquake (Mw = 9.5). Utilizing onshore recordings of the airgun sources and additional onshore and offshore sources, a combined onshore-offshore, active-passive seismic project between 36°S and 39°S was realized. This project comprised i) a pilot near-vertical incidence reflection (NVR) seismic experiment covering the onshore-offshore transition along an E-W line at 38°15´S, ii) three consecutive E-W wide-angle reflection / refraction (WRR) lines at 36°20´S, 37°15´S and 38°15´S, iii) an array of 30 stations for recording both active and passive sources and iv) six broadband stations along a profile at 39°S.
In December 1998 the BGR recorded a network of combined reflection/refraction lines offshore Argentinia using streamer and OBHs. In order to close the gap between land and marine survey and to test the general propagation of signals for later projects in this area, additional receivers on land have been deployed, recording the airgun signals from the WE-trending OBH refraction line BGR98-REF1 also onshore. It turned out, that the airgun signals could be recorded with remarkable quality from the eastern end of the marine refraction line (500 km offshore) to the western end of the land stations (150 km onshore), i.e. up to distances of 650 km.
The TICOSECT program aims to investigate the crustal structure of the active continental margin of Costa Rica and to understand the geodynamic processes within the subduction system. With the help of a comprehensive wide-angle seismic data set, composed of an onshore/offshore experiment as well as refraction measurements on land in northern Costa Rica, the lithospheric structure from the Middle America Trench (MAT) to the Caribbean lowland have been modelled.
The vision of this integrated study is a quantitative understanding of megathrust earthquake seismicity in subduction zones and its relation to processes at depth and at the surface.
The TRACK project is intended to complement the Eifel-plume project and will connect the former with the existing Auvergne ("Massif Central plume") network, allowing investigation of sub-lithospheric mantle structure as far south as the Golf of Lion.
Within the project URSEIS 95 a 400 km long traverse crossing the Southern Urals was recorded by application of both, near-vertical and wide-angle seismic methods. High-resolution images of the near-vertical sections as well as P- and S-wave modelling of the wide-angle data demonstrate the presence of a 15-18 km thick crustal root beneath the central part of the Urals orogen. The high velocities and densities in the crustal root can be most easily explained by mafic rocks or a mix of mafic and ultramafic rocks belonging to the Russian plate which was being subducted beneath the Siberian plate during the Uralian orogeny.