caa a22 4500 606149155 CHVBK 20210128100532.0 cr unu---uuuuu 210128e20150901xx s 000 0 eng 10.1007/s00531-015-1147-5 doi (NATIONALLICENCE)springer-10.1007/s00531-015-1147-5 Downhole geophysical observatories: best installation practices and a case history from Turkey [Elektronische Daten] [Bernhard Prevedel, Fatih Bulut, Marco Bohnhoff, Christina Raub, Recai Kartal, Fatih Alver, Peter Malin] Downhole sensors of different types and in various environments provide substantial benefit to signal quality. They also add the depth dimension to measurements performed at the Earths' surface. Sensor types that particularly benefit from downhole installation due to the absence of near-surface noise include piezometers, seismometers, strainmeters, thermometers, and tiltmeters. Likewise, geochemical and environmental measurements in a borehole help eliminate near-surface weathering and cultural effects. Installations from a few hundred meter deep to a few kilometer deep dramatically reduce surface noise levels—the latter noticeably also reduces the hypocentral distance for shallow microearthquakes. The laying out of a borehole network is always a compromise of local boundary conditions and the involved drilling costs. The installation depth and procedure for a long-term downhole observatory can range from time limited installations, with a retrieval option, to permanently cemented sensors. Permanently cemented sensors have proven to be long-term stable with non-deteriorating coupling and borehole integrity. However, each type needs to be carefully selected and planned according to the research aims. A convenient case study is provided by a new installation of downhole seismometers along the shoreline of the eastern Marmara Sea in Turkey. These stations are being integrated into the regional net for monitoring the North Anatolian Fault Zone. Here we discuss its design, installation, and first results. We conclude that, despite the logistical challenges and installation costs, the superior quality of downhole data puts this technique at the forefront of applied and fundamental research. The Author(s), 2015 Downhole observatory nationallicence Permanent monitoring nationallicence Seismometer nationallicence Fault system nationallicence North Anatolian Fault Zone nationallicence Earthquake research nationallicence Prevedel Bernhard Helmholtz-Centre Potsdam GFZ German Centre for Geosciences, Telegrafenberg, 14473, Potsdam, Germany aut Bulut Fatih Helmholtz-Centre Potsdam GFZ German Centre for Geosciences, Telegrafenberg, 14473, Potsdam, Germany aut Bohnhoff Marco Helmholtz-Centre Potsdam GFZ German Centre for Geosciences, Telegrafenberg, 14473, Potsdam, Germany aut Raub Christina Helmholtz-Centre Potsdam GFZ German Centre for Geosciences, Telegrafenberg, 14473, Potsdam, Germany aut Kartal Recai AFAD, Disaster and Emergency Management Presidency, Ankara, Turkey aut Alver Fatih AFAD, Disaster and Emergency Management Presidency, Ankara, Turkey aut Malin Peter IESE, University of Aukland, Aukland, New Zealand aut International Journal of Earth Sciences Springer Berlin Heidelberg 104/6(2015-09-01), 1537-1547 1437-3254 104:6<1537 2015 104 531 https://doi.org/10.1007/s00531-015-1147-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00531-015-1147-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Prevedel Bernhard Helmholtz-Centre Potsdam GFZ German Centre for Geosciences, Telegrafenberg, 14473, Potsdam, Germany aut NATIONALLICENCE 700 1- Bulut Fatih Helmholtz-Centre Potsdam GFZ German Centre for Geosciences, Telegrafenberg, 14473, Potsdam, Germany aut NATIONALLICENCE 700 1- Bohnhoff Marco Helmholtz-Centre Potsdam GFZ German Centre for Geosciences, Telegrafenberg, 14473, Potsdam, Germany aut NATIONALLICENCE 700 1- Raub Christina Helmholtz-Centre Potsdam GFZ German Centre for Geosciences, Telegrafenberg, 14473, Potsdam, Germany aut NATIONALLICENCE 700 1- Kartal Recai AFAD, Disaster and Emergency Management Presidency, Ankara, Turkey aut NATIONALLICENCE 700 1- Alver Fatih AFAD, Disaster and Emergency Management Presidency, Ankara, Turkey aut NATIONALLICENCE 700 1- Malin Peter IESE, University of Aukland, Aukland, New Zealand aut NATIONALLICENCE 773 0- International Journal of Earth Sciences Springer Berlin Heidelberg 104/6(2015-09-01), 1537-1547 1437-3254 104:6<1537 2015 104 531