GEOFON (GEOFOrschungsNetz - Geo Research Network)

This project makes broadband seismological recordings of global earthquakes at Summit, Greenland. Formerly a part of the temporary GLATIS network, project responsibility has been turned over to GFZ Potsdam. Summit instruments have been included in that institute's GEOFON network. The project will deploy personnel to Summit Station as required to service and maintain the seismological station. Project personnel have visited Summit numerous times since 2002, with work including system maintenance, upgrades and relocations. The current system now enables remote monitoring, control, and physical re-leveling. Over the years, in addition to the scheduled maintenance, project personnel have visited Summit for various other project needs. Summit staff will assist as needed with excavation and maintenance activities. Year-round, science technical staff will re-level the instrument and provide as-needed assistance. In 2002, they installed an upgraded datalogger for the seismological station and a "Seiscomp" box that connected the station to the Summit LAN for Internet real-time data transmission; in 2004, another major station upgrade overcame technical problems and minimized required local support; in 2007, two technicians raised and relocated the seismometer bunker, routing power and communications connections out of the Temporary Atmospheric Watch Observatory. In 2009, a technician visited in May to conduct minor maintenance on the seismometer. Year-round, science technical staff will re-level the instrument and provide as-needed assistance. In 2010, a team of two researchers returned in July. The seismometer bunker was raised and relocated to a new site so that power and communications can continue to be connected out of the Temporary Atmospheric Watch Observatory, which was also relocated during this time. In 2011, one researcher returned in mid-June to conduct minor maintenance on the seismometer. In 2012, two researchers returned to Summit Station in July to conduct minor maintenance on the seismometer. In 2013, two researchers relocated the seismometer to a new trench and replaced the cable. Summit staff will assist as needed with excavation and maintenance activities. Year-round, science technical staff will re-level the instrument and provide as-needed assistance. In 2014, no researchers will deploy to Summit Station. Instead, station staff assisted with excavation of the bunker and maintenance activities as needed. In 2015, two researchers deployed to Summit Station in June to perform maintenance on the seismometer system, including relocating it to a new vault, raising all cables above the snow surface and checking out all hardware. No researchers deployed in 2016. Instead, station technical staff replaced a broken seiscompbox. In 2017, two researchers visited in May to perform maintenance on the seismometer system, including relocating it to a new vault, raising all cables above the snow surface, and checking out all hardware. No researcher travel is planned for 2018. In 2019, two members of the project team will travel to Summit to relocate the seismic system to a new adjacent site. As part of this work, they will inspect the current seismic system hardware and raise the cable lines above the snow surface. The post hole seismometer, which had been installed for an inter-comparison period, will be used at the new site. The project team will determine once onsite whether to decommission a second older seismometer or to extend parallel operations with the post-hole seismometer. In 2020 and 2021, the project team will not deploy. The on-site science technicians will continue to monitor the experiment, regularly raise the cables between the TAWO and the seismometer and provide onsite support as needed. Discussions and onsite measurements will prepare for the anticipated raising and reconfiguration of the posthole seismometer sensor in 2022.