Injection-induced earthquakes and crustal stress at 9 km depth at the KTB deep drilling site, Germany

Constraining Crustal Anisotropy by Receiver Functions at the Deep Continental Drilling Site KTB in Southern Germany

As one of the rare observational tools for studying deformation and stress within the Earth, seismic anisotropy has been one of the focuses of geophysical studies over the last decade. In order to unravel the anisotropic properties of the crust, the teleseismic receiver functions (RF) methodology has started to be widely applied recently. Such effects of anisotropy on RF were illustrated in the...

Imaging the Variscan suture and deformation at the KTB deep drilling site, Germany

Drilling Induced Core Fractures and Crustal Stress

Drilling induced core fractures, usually ignored in standard core logging, contain substantial information on the directions of horizontal stresses and the relative magnitudes of the three principal stresses. These fractures have a variety of shapes, variously referred to as petal, petal-centreline, saddle, cup, and scallop. Surprisingly, the morphology of the fractures suggests they are produc...

Deformation, seismicity, and fluids: Results of the 2004/2005 water injection experiment at the KTB/Germany

[1] During the past decades, the research into fluid-controlled geodynamic processes in the upper crust of the Earth is put foreward regarding the stress accumulation, deformation, and seismicity. In a large-scale injection experiment at the deep borehole site KTB (Kontinentale Tiefbohrung der Bundesrepublik Deutschland) in Germany, more than 84.000 m fresh water was injected in 4000 m depth ov...

Repeating deep earthquakes: evidence for fault reactivation at great depth.

We have identified three groups of deep earthquakes showing nearly identical waveforms in the Tonga slab. Relocation with a cross-correlation method shows that each cluster is composed of 10 to 30 earthquakes along a plane 10 to 30 kilometers in length. Some of the earthquakes are colocated, demonstrating repeated rupture of the same fault, and one pair of events shows identical rupture complex...