Developing Geodetic Tools for Early Warning and Monitoring

Developing Geodetic Tools for Early Warning and Monitoring of Tectonic Activity at the Gulf of Cadiz Jorge Gárate, Javier Ramírez Zelaya, Belén Rosado, Manuel Berrocoso, Amos de Gil, Alberto Fernández Ros, Gonçalo Prates, and Luis Miguel Peci Laboratory of Astronomy, Geodesy and Cartography, Faculty of Sciences, Department of Mathematics, University of Cádiz ABSTRACT Gulf of Cadiz from the Strait of Gibraltar to the Western Coast of the Iberian Peninsula is a natural hazard risky region due to the existence of several active faults related to the Eurasian and Nubian Plate interaction. The 1755 Lisbon Earthquake was remarkable example. With the epicenter located SW of Cape San Vicente, and a Richter scale magnitude around 8. 3, the earthquake triggered a devastating tsunami hitting the Portuguese, Moroccan and Southern Spain coasts, resulting in thousands of casualties. More recently, in 1969 a 7. 8 magnitude earthquake with its epicenter located in the same region, originated another tsunami but smaller than the previous one, resulting nineteen casualties. To prevent natural hazards like these, the Astronomy, Geodesy and Cartography Laboratory at the Universidad de Cadiz, is drawing and implementing early warning systems, trying to detect and evaluate tectonic activity in near real time at the Gulf of Cadiz. The system includes the GNSS network SPINA receivers together with MEMS accelerometers, meteo equipments, and ancillary instrumentation for data acquisition, monitoring, quality control and results display at a dedicated control center. 2 B 2 A Fig. 1: Earthquake location map in the Gulf of Cádiz region, magnitudes greater than 3. 0 since 2000. (Source: IGNE seismic catalog). The mark indicates the approximate location of the earthquake that occurred on November 1, 1755. Fig. 2: A. Tectonic limits and seismicity in the southern Iberia region, arrows indicate relative movements of main plates and tectonic blocks. The dashed line shows the inferred boundary between the continental and oceanic lithosphere. B. Three-dimensional block diagram indicating the sinking and receding of the oceanic lithosphere belonging to the African plate (Gutscher, M. A. 2004). Design and Hardware Structure of the proposed Seismic Geodetic System Seismic geodetic monitoring Fig. 6: Hardware diagram of the geodetic seismic system for monitoring and surveillance of tectonic activity in the Gulf of Cádiz. Surveillance and detection instruments 7 A Fig. 3: GNSS-GPS receiver located on the roof of the LAGC-UCA. 7 B Fig. 8: Pilot seismic geodetic station installed on the roof of the LAGC, to monitor tectonic activity in the Gulf of Cádiz, consisting of a geodetic GNSS receiver, a weather station and an accelerometer. Fig. 4: MET 3 A Weather Station on the rooftop LAGC-UCA. Fig. 7 A y 7 B: Low cost digital inclinometers MEMS, installed on the roof of the LAGC (7 A) and UCA basement (7 B). Inclination and acceleration parameters are obtained in two perpendicular (biaxial) axes with long-term observations, with maximum resolution and sensitivity. Station MET 3 A Fig. 9: Integration of a (generic) inclinometer, a seismic sensor (Raspberry shake 4 D) with a low cost (Raspberry PI 4) acquisition system. This pilot station is installed in the basement of the UCA and is managed by the LAGC. MEMS TILT LOGGER 8 Acquisition System Raspberry PI 4 5 A Datalogger 5 B Inclinometer (Low cost) Fig. 5 A y 5 B: Geodynamic model of the southern region of the Iberian Peninsula and North Africa (SPINA). 5 A. Models of velocities and displacements, 5 B. Residual models with respect to the Eurasian plate, (Rosado et al. 2017). GNSS Surveillance Adaptation of new modules to the "DIESID" real-time system implemented on Deception Island of Antarctica. Acquisition and Processing Software Description ACQUISITION VISUALIZATION PROCESSING HARDWARE TOOLS SCP, SFTP, RSync RTKLIB HYPERVISOR COMMUNICATION NETWORKS TEQC_PYTHON BERNESE CITRIX_VMWARE GSAC_SERVER SIGNALS CONVETERS GIPSY_OASIS VIRTUAL_MACHINE CMS_HTML GAMIT_GLOBK DATA TRANSFER SERVICES (SCP, SCFTP, RSYNC) ANALYSIS PYTHON DATA FILTERING MATLAB OCTAVE RESULTS 12 A Hardware components for data acquisition, management and control VIRTUAL INFRASTRUCTURE WEB PUBLISH Fig. 11: Infrastructure of the integrated automatic system “DIESID" for the volcanic surveillance of Deception Island, (a) remote node BEGC, (b) repeater node FUMA, (C) remote node PEND and (d) control center, located at the base " Gabriel de Castilla ”. GNSS Antenna R Fig. 13: Diagram of the proposed software dedicated to the acquisition, storage, processing, quality control, analysis, filtering (noise signal analysis) and publication of the data obtained from the seismic geodetic network for monitoring and surveillance of tectonic activity in the Gulf of Cádiz. LINUX OS SERVER USER MANAGEMENT XEN_CENTER Sismometer (Raspberry Shake 4 D) 9 The joint and integrated treatment of the data obtained (displacements) will provide GPS topocentric series with less noise than if they were exclusively GPS, and consequently it will be possible to measure co-seismic, post-seismic or transient displacements, even in the absence of tectonic movements, their location and the extent of the rupture plane. Integration in a Early Warning System DATA STORAGE (NAS, CLOUD_IN_OUT) SECURITY AND DATA AVAILABILITY (IP_TABLES, FIREWALL) Fig. 14: Virtual and physical infrastructure proposed for the acquisition, storage, processing, control, security and availability of the data obtained from the seismic geodetic network. The operating systems to be used are shown, as well as the different phases of data communication, management, control and security. Seismic Geodetic Stations Network in the Gulf of Cádiz It shows the location and classification of the types of instruments that will be installed in the Gulf of Cádiz network. GNSS TRACKING 1 GNSS TRACKING 2 Fig. 10: General outline of an early warning system. The element to which this work is directed is indicated (Monitoring and alert system). Bibliography GNSS SURVEILLANCE Berrocoso, M. , Páez, R. , Jigena, B. and Caturla, C. (2006 c). The RAP Net: A geodetic positioning network for Andalusia (south Spain). EUREF Publication 16: Mitteilungen des Bundesamtes für Kartographie and Geodaesie, v. 40, p. 364 -368. WEATHER STATIONS 12 B ACCELEROMETERS Fig. 12 A y 12 B: Variation in distances between stations BEGC_FUMA (12 A) and BEGC_PEND (12 B) obtained with the DIESID system (both series have been treated with Wavelets analysis). INCLINOMETERS N SEISMIC STATION GNSS STATIONS IGS & EUREF NETWORKS Fig. 15: Map of the Network of GNSS-GPS seismic geodetic stations for monitoring and surveillance of tectonic activity in the Gulf of Cádiz. Rosado, B. , Barbero, I. , Jiménez, A. , Páez, R. , Prates, G. , Fernández-Ros, A. , Berrocoso, M. (2016). SPINA Region (South of Iberian Peninsula, North of Africa) GNSS Geodynamic Model. In: Freymueller J. T. , Sánchez L. (eds) International Symposium on Earth and Environmental Sciences for Future Generations. International Association of Geodesy Symposia, 147. Springer, Cham. Peci, L. M. , Berrocoso, M. , Páez, R. , Fernández-Ros, A. , De Gil, A. (2012). DIESID: Automatic system for monitoring ground deformation on Deception Island volcano (Antarctica). Computers & Geosciences 48. Gutscher, M. A. 2004. What caused the Great Lisbon Earthquake? Science, 305, 1247 -1248. DOI: 10. 1126/science. 1101351.