A 20-yr database (1997-2017) of co-seismic displacements from GPS recordings in the Aegean area and their scaling with Mw and hypocentral distance

Στην παρούσα εργασία περιγράφουμε και διαθέτουμε μία βάση εξήντα τεσσάρων (64) σεισμικών μετατοπίσεων από τις καταγραφές μόνιμων σταθμών GPS, κατά την εικοσαετή χρονική περίοδο 1997-2017. Οι μετατοπίσεις οφείλονται σε μεγάλους, επιφανειακούς σεισμούς στον Ελληνικό χώρο οι οποίοι προκάλεσαν επιφανειακές κινήσεις (της τάξεως χιλιοστών έως δεκάδων εκατοστών) ανιχνεύσιμες από δίκτυα GPS-GNSS. Στην βάση περιλαμβάνονται δεδομένα μόνιμης μετατόπισης για αποστάσεις μεταξύ 2-132 km από το υπόκεντρο και για 11 σεισμούς με μεγέθη ροπής μεταξύ 5.5≤Mw≤6.9. Αυτά τα δεδομένα είναι χρήσιμα σε γεωλόγους, σεισμολόγους και μηχανικούς επειδή συμβάλουν στην πληρέστερη κατανόηση της μηχανικής των διαρρήξεων, της κατανομής των επιφανειακών παραμορφώσεων μετά από μεγάλους σεισμούς αλλά και σε άλλες εφαρμογές σεισμικής μηχανικής. Επιπλέον, έγινε ανάλυση με πρώτη νόρμα (L1- norm) παλινδρόμησης της απόσβεσης της μόνιμης, οριζόντιας επιφανειακής μετατόπισης συναρτήσει του μεγέθους και υποκεντρικής απόστασης. Βρήκαμε ότι τα δεδομένα μας ταιριάζουν καλύτερα με μία γραμμική συμπεριφορά για αυτό το εύρος μεγεθών. Προτείνουμε δύο εμπειρικές σχέσεις για τον υπολογισμό του σεισμικού μεγέθους βάσει της εδαφικής μετατόπισης και της αποστάσεως από το υπόκεντρο, οι οποίες μπορούν να χρησιμοποιηθούν εφόσον είναι διαθέσιμες επιλύσεις σταθμών σε σχεδόν-πραγματικό χρόνο.We describe and make available a dataset of 64 data points of Global Positioning System (GPS) displacements for significant, shallow earthquakes in Greece during the period 1997-2017. The displacement data can be used by earthquake geologists, engineers and seismologists in an effort to better understand the faulting process, the rupture mechanics, the pattern of ground-motions, and in engineering applications. We include recordings from GNSS networks at near-source to regional distances (2–132 km) for 11 earthquakes between global CMT moment magnitudes (Mw) 5.5 and 6.9. We also model the magnitude scaling properties of peak ground horizontal displacements (PGD and PGD-S) for these events using L1-norm minimisation regression. Our data indicate an almost linear attenuation of seismic strain with distance for this range of seismic magnitudes. We developed a set of relationships based on PGD (in cm) and distance to hypocentre R (in km), which may be used for the rapid estimation of the earthquake magnitude in near real-time.MwPGD = [LOG(PGD) + 8.2849]/(1.6810 – 0.2453LOGR)MwPGD-S = [LOG(PGD-S) + 8.0839]/(1.6793 – 0.2447LOGR

Geodetic evidence for post-seismic deformations following the 2014 North Aegean Mw 6.9 earthquake

The 2014 North Aegean Sea earthquake was a strong (Mw 6.9) event that caused significant crustal deformations. In the present study we investigate the long-term impact of the earthquake on the kinematics of the North Aegean Trough (NAT). For this purpose, we analyzed GPS observations collected from May 2010 to April 2022 at five permanent GPS reference stations. Two of these stations are located close to the epicenter(s) on the Islands of Lemnos and Samothrace. We processed the data using the Precise Point Positioning (PPP) technique. The analysis of the obtained coordinate time-series revealed a post-seismic deformation (PSD) period lasting for more than two years leading to cumulative 2D post-seismic displacement of 22 mm and 27 mm for Samothrace and Lemnos, respectively. The magnitudes of these post-seismic slip vectors correspond to 23% and 49% of the co-seismic vectors at Samothrace and Lemnos, respectively. The long-term analysis showed that after the end of the PSD period the stations are characterized by stable velocities that are noticeably different compared to the velocities prior to the event. We observed a change in the velocity in the order of 2 mm/yr for both Samothrace and Lemnos. It is the first time that PSD and velocity changes have been reported for the 2014 North Aegean Sea earthquake shedding light on the characteristics and the impact of this important earthquake on the kinematics of NAT

7Factor Staffing Tool

7Factor Software is a consulting company that completes projects for clients on a contract basis. They need to track the time each employee spends on each project so they can bill their clients correctly. They also track their staff utilization so they can book the correct number of new contracts to ensure every employee is working on paid tasks. In this project we present how we designed a web platform to fulfill those needs and implemented several of the back-end and front-end components. We also describe the future work needed to complete the application

Relief Housing in Yemen

https://digitalcommons.wpi.edu/gps-posters/1606/thumbnail.jp

Landslide Monitoring Using Geotechnical, UAV, GNSS and MTInSAR Instrumentation

[EN] Many mountainous villages have been struck by landslides in Western Greece due to growing urbanization and uncontrolled land use in landslide prone areas, without considering the engineering geological environment. The presence of the tectonically highly sheared and weathered geological formations of the alpine basement (such as flysch) and the intense geomorphological relief, strongly contribute to the periodically induced instability phenomena mainly triggered by heavy rainfalls and extreme meteorological events. The current research combines long-term monitoring of the parameters connected to the landslide activity with the real-time kinematics observation in a dense-populated mountainous village located in the Region of Epirus in Greece. The landslide movements evolve very low velocity values at different depths; thus, the landslide cases can be characterized as complex and "extremely slow". The long-term monitoring is carried out by several in-place and portable inclinometer probes that permit the detailed observation of subsurface displacements for an extended period. In addition, GNSS measurements, very high-resolution multitemporal interferometry (accompanied with the installation of corner reflectors) and Unmanned Aerial Vehicle (UAV) photogrammetric surveys are used for the monitoring of surface deformation. All instrumentation is installed in the wider area of the landslide zone and one of the main goals of this approach is to combine long-term monitoring of the parameters connected to the landslide activity with the observation of the landslide kinematics in real-time.This research was funded by the Regional Operation Programme Epirus 2014-2020. We would also like to acknowledge Deutsches Zentrum für Luft und Raumfahrt (DLR) to provide the TERRASAR-X satellite acquisitions within the science project GEO3659 as well as the TREE company for providing the data of the GNSS station GARD of the URANUS network.Depountis, N.; Kavoura, K.; Nikolakopoulos, K.; Drakatos, G.; Argyrakis, P.; Elias, P.; Sabatakakis, N. (2023). Landslide Monitoring Using Geotechnical, UAV, GNSS and MTInSAR Instrumentation. Editorial Universitat Politècnica de València. 207-2013. https://doi.org/10.4995/JISDM2022.2022.13818207201

Characteristics of Recent Aftershocks Sequences (2014, 2015, 2018) Derived from New Seismological and Geodetic Data on the Ionian Islands, Greece

In 2014–2018, four strong earthquakes occurred in the Ionian Sea, Greece. After these events, a rich aftershock sequence followed. More analytically, according to the manual solutions of the National Observatory of Athens, the first event occurred on 26 January 2014 in Cephalonia Island with magnitude ML = 5.8, followed by another in the same region on 3 February 2014 with magnitude ML = 5.7. The third event occurred on 17 November 2015, ML = 6.0 in Lefkas Island and the last on 25 October 2018, ML = 6.6 in Zakynthos Island. The first three of these earthquakes caused moderate structural damages, mainly in houses and produced particular unrest to the local population. This work determines a seismic moment tensor for both large and intermediate magnitude earthquakes (M > 4.0). Geodetic data from permanent GPS stations were analyzed to investigate the displacement due to the earthquakes

Characteristics of Recent Aftershocks Sequences (2014, 2015, 2018) Derived from New Seismological and Geodetic Data on the Ionian Islands, Greece

In 2014–2018, four strong earthquakes occurred in the Ionian Sea, Greece. After these events, a rich aftershock sequence followed. More analytically, according to the manual solutions of the National Observatory of Athens, the first event occurred on 26 January 2014 in Cephalonia Island with magnitude ML = 5.8, followed by another in the same region on 3 February 2014 with magnitude ML = 5.7. The third event occurred on 17 November 2015, ML = 6.0 in Lefkas Island and the last on 25 October 2018, ML = 6.6 in Zakynthos Island. The first three of these earthquakes caused moderate structural damages, mainly in houses and produced particular unrest to the local population. This work determines a seismic moment tensor for both large and intermediate magnitude earthquakes (M > 4.0). Geodetic data from permanent GPS stations were analyzed to investigate the displacement due to the earthquakes

Oteima Batipa Water Sustainability IQP Paper A19

Comprehending the potential and abundance in the Chiriquí providence, Batipa Field Institute (BFI), believes it would be beneficial to install a rainwater harvesting (RWH) system. This project focuses on proposing a RWH system for BFI, while creating an educational, cost-effective model applicable for the Panamanian public. This was accomplished through exploring Panama’s relationship with the environment and sustainability, communication with other biological research stations, and finally formulating our findings into a model using AutoCAD 2019