No abstract

Earthquake locations along the southern Mid‐Atlantic Ridge have large uncertainties due to the sparse distribution of permanent seismological stations in and around the South Atlantic Ocean. Most of the earthquakes are associated with plate tectonic processes related to the formation of new oceanic lithosphere, as they are located close to the ridge axis or in the immediate vicinity of transform faults. A local seismological network of ocean‐bottom seismometers and land stations on and around the archipelago of Tristan da Cunha allowed for the first time a local earthquake survey for 1 year. We relate intraplate seismicity within the African oceanic plate segment north of the island partly to extensional stresses induced by a bordering large transform fault and to the existence of the Tristan mantle plume. The temporal propagation of earthquakes within the segment reflects the prevailing stress field. The strong extensional stresses in addition with the plume weaken the lithosphere and might hint at an incipient ridge jump. An apparently aseismic zone coincides with the proposed location of the Tristan conduit in the upper mantle southwest of the islands. The margins of this zone describe the transition between the ductile and the surrounding brittle regime. Moreover, we observe seismicity close to the islands of Tristan da Cunha and nearby seamounts, which we relate to ongoing tectono‐magmatic activity.

<p>As part of the “Deutsches Seismologisches Breitband Array” (DSEBRA), a mobile station array of 100 identical seismological broadband stations, the remote monitoring devices “PowBox” were developed by the Ludwig-Maximilians-Universität München.</p> <p>The PowBoxes log and report the health status of the autonomously operating seismological stations, such as 12V/230V availability or battery temperature. With their various fail-safes the most common issues such as router and battery charger problems are fixed by automatic power resets and efforts and costs on unnecessary maintenance trips can be reduced.</p> <p>More than 80 PowBoxes are now in operation for the first time with the deployment of the DSEBRA stations in South-East Europe as part of the AdriaArray project, a follow-up to the successful AlpArray project.</p> <p>To ensure a good overview for the network operator, the modular Python software tool “survBot” was developed at the Ruhr-Universität Bochum. It analyses the different state-of-health channels of the PowBox and the Datalogger, displays them in a graphical user interface or as a html-webpage and informs about emerging problems via e-mail. It is openly available on github.</p>