(Fig.57)
As I already mentioned, the unique constellation of two deep boreholes which are completely accessible and which are only at a distance of 200 m from each other, allow for a variety of highly sophisticated experiments： surface-to-borehole, borehole-to-borehole, and also long-term monitoring of geo-processes.
The next major experiment which will be carried out as an ICDP co-financed experiment with partners in the US and Japan and in Germany is a vertical seismic and moving source profiling experiment. This shows the schematic layout of this experiment which will start in a few days.
(Fig. 58)
Already in preparation is another large-scale hydrofrac experiment in the super-deep borehole, which will be carried out next year, again as a co-financed German-Japanese-US- ICDP joint project. This experiment is designed to provide detailed insight into the rheologic behaviour of the crust. New information is expected with respect not only to the stress field but especially with respect to the frac-propagation, frac-generation, and by the evaluation of these data we hope to really get fundamental information as to the reasons why earthquakes are generated.
(Fig.59)
As a result of a very successful ICDP workshop held in Qingdao in August 1997, the Chinese Government decided to provide funding for the first Chinese deep continental drilling project, which will be also co-financed by ICDP and will be carried out as a joint ICDP-Chinese project here in the DaBie-Sulu Belt in the area of Central-East China.
(Fig.60)
The plan is to drill into ultra-high pressure rocks to a depth of 5 km. This year we will start with a one to two kilometer pilot hole. Detailed seismic surface investigations have been carried out last year, so we know the area relatively well, and the main borehole will be started next year. The scientific target is to study the process of deep subduction and rapid exhumation of continental lithosphere, and one of the principal investigators - Paul Robinson from Canada-is among us.
(Fig. 67)
Lake Titicaca is expected to contain one of the most significant climatic archives in all of South America, and therefore has been identified as a high priority target by PAGES - the Past Climate Changes study group. This is a project in the framework of the Pole-Equator-Pole transect across America. The Lake Titicaca drilling program will especially provide information related to the E1 Nino phenomenon which can be studied there in great detail, and also about the sub-recent tectonic evolution of the Andes in that region. Just presently, a seismic survey is being conducted on the lake, and drilling is expected to be carried out next year. Three drill holes are presently being planned.
(Fig.66)
The idea of probing the Chicxulub impact structure by a deep borehole was already outlined at the Potsdam conference. You saw it on the front cover of this document. Meanwhile new seismic data are available from the British Seismic Group and their BIRPS experiment.
