DIVEnet, an example of drilling monitoring

<p>The DIVEnet is the ICDP DIVE project dedicated seismographic network. The ICDP DIVE project (www.dive2ivrea.org) is aimed at addressing fundamental questions on the nature of the lower continental crust and its transition to the mantle through two drillings in the Ivrea Verbano zone (IVZ), considered the world's best outcrop of lower crustal continental rocks. Between September and December 2022 the first drilling has been done in Ornavasso. To be ready for its monitoring the DIVEnet has started to record continuously since November 2021.&#160;<br />The network includes 11 seismic stations located within a 17.7 km radius from the drilling site. Additionally, the stations from the CH (Switzerland), GU (University of Genova) and IV (INGV) networks are used to locate the detected earthquakes.&#160;</p> <p>Before the beginning of the drilling the acquired data have been analyzed checking for daily and sub-daily continuity and, when needed, recovery acquisition gaps. After the data recovery, the total loss in the period span between November 2021 and 20 December 2022, date when the drilling stopped, is less than 2% and 5% in daily and sub-daily missing data, respectively.&#160;<br />Furthermore, probabilistic power spectral densities (PPSD) analysis has been conducted monthly and for the entire period (11-2021 / 12-2022).</p> <p>The drilling started on the 6 of October, showing no significant changes in the noise spectrum at each station, included those close to the drilling site. Real time analysis has been conducted from the beginning of the drilling with the automatic detection of local earthquakes counting less than 20 small events in the period between 1 October and 20 December.</p> <p>Several automated codes have been developed to daily analyze, localize and eventually plot on map the events falling inside the network. Currently the workflow include a set of Python scripts followed by SeisComP calls for automatic earthquakes detection and localization; &#160;the set of scripts comprises codes to: daily checks for earthquakes, weekly checks for gaps and, if necessary, download lost data, monthly analysis of PPSD and HTML-report creation with map location earthquakes.&#160;</p> <p>This routine would make future analysis faster and cleaner during the second drilling planned in Megolo in spring 2023 as well as other real time seismic analysis.</p>