Heat Flow, Electrical Conductivity and Seismicity in the Black Forest Crust, SW Germany

  1. Robert F. Mereu,
  2. Stephan Mueller and
  3. David M. Fountain
  1. H. Wilhelm1,
  2. A. Berktold2,
  3. K.-P. Bonjer1,
  4. K. JäGer1,
  5. A. Stiefel1 and
  6. K.-M. Strack3

Published Online: 9 APR 2013

DOI: 10.1029/GM051p0215

Properties and Processes of Earth's Lower Crust

Properties and Processes of Earth's Lower Crust

How to Cite

Wilhelm, H., Berktold, A., Bonjer, K.-P., JäGer, K., Stiefel, A. and Strack, K.-M. (2013) Heat Flow, Electrical Conductivity and Seismicity in the Black Forest Crust, SW Germany, in Properties and Processes of Earth's Lower Crust (eds R. F. Mereu, S. Mueller and D. M. Fountain), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM051p0215

Author Information

  1. 1

    Geophysikalisches Institut, UniversitäT Karlsruhe Hertzstr. 16, D-7500 Karlsruhe 21, F.R. Germany

  2. 2

    Institut FüR Allgemeine Und Angewandte Geophysik, UniversitäT MüNchen, Theresienstr. 41/Iv, D-8000 MüNchen 2, F. R. Germany

  3. 3

    Institut FüR Geophysik Und Meteorologie, UniversitäT KöLn, Albertus-Magnus-Platz, D-5000 KöLn 1, F. R. Germany

Publication History

  1. Published Online: 9 APR 2013
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780875904566

Online ISBN: 9781118666388

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Keywords:

  • Earth—Crust—Congresses;
  • Geophysics—Congresses

Summary

Several geophysical site surveys have been performed in the Black Forest, southwest Germany, for the German Continental Deep Drilling Program (KTB) during 1984 to 1986. Besides seismic reflection and refraction measurements and lD and 2D gravity and magnetic field surveys investigations of surface heat flow and of the crustal electrical conductivity structure were carried out. Also, the seismici ty record and results from repeated levellings since 1922 in the Rhinegraben region were inspected. This paper concentrates on the results of heat flow and seismicity observations and of magnetotelluric, magnetovariational and electromagnetic investigations. the surface heat flow shows a regional decline from about 90 mW/m2 in the North to about 70 mW/m2 in the central Black Forest on a horizontal scale of 30 km. the electrical conductivity is anomalously high at midcrustal level, and in the envisaged drilling area near Haslach a well-conducting layer was detected at 7 to 9 km depth by long offset transient electromagnetic (LOTEM) recordings. A correlation to a pronounced midcrustal seismic low velocity layer is presumed. the seismicity shows a regional variation in frequency and hypocenter depth distribution. A common interpretation of the results of the different kinds of observations is facilitated if the crustal properties are significantly influenced by the presence of fluids.