7 documents found in 180ms
# 1
Lühr, Birger • Ibanez, Jesus M. • Dahm, Torsten
Abstract: The TOMO-ETNA experiment was focused on the base of generation and acquisition of seismic signal (active and passive) at Mt. Etna volcano and surrounding area. The terrestrial campaign consists in the deployment of 80 short-period three-component seismic stations (June 15 to July24), 17 Broadband seismometers (June 15 to October 30) provided by Helmholtz Centre Potsdam (GFZ) German Research Centre for Geosciences using the German Geophysical Instrument Pool Potsdam (GIPP Gerätepool Geophysik), and the coordination with 133 permanent seismic station belonging to the “Istituto Nazionale di Geofisica e Vulcanologia” (INGV) of Italy. This temporary seismic network recorded active and passive seismic sources. Active seismic sources were generated by an array of air-guns mounted in the Spanish Oceanographic vessel “Sarmiento de Gamboa” with a power capacity of up to 5.200 cubic inches. In total more than 26.000 shots were fired and more than 450 local and regional earthquakes were recorded. Until July the Oceanographic Vessel “Sarmiento de Gamboa” and the hydrographic vessel “Galatea” were responsible for the offshore activities, that included deployment of OBSs, and several marine activities. The vessel “Aegaeo” performed additional seismic, magnetic and gravimetric experiments until the end of November 2014. This experiment was part of the “Task 5.3 - Mt. Etna structure” of the “EU MED-SUV Project” concerned with the investigation of Mt. Etna volcano (seismic tomography experiment - TOMO-ETNA) by means of passive and active refraction/reflection seismic methods. It focused on the investigation of Etna’s roots and surrounding areas by means of passive and active seismic methods. Therefore, this experiment included activities both on-land and offshore with the main objective to obtain a new high-resolution tomography in order to improve the 3D image of the crustal structures existing beneath the Etna volcano and the northeast Sicily (Peloritani - Nebrodi chain) up to the Aeolian Islands. Waveform data are open and available from the GEOFON data centre, under network code 1T.
# 2
Passarelli, Luigi • Govoni, Aladino • Francesco, Maccaferri • Woith, Heiko • Strollo, Angelo • (et. al.)
Abstract: The aim of this temporary experiment is to monitor the interaction between crustal fluids and earthquake occurrence. Two sites have been initially investigated: one is in the eastern sector of the Pollino mountain range, located at the border of Southern Apennines chain and Calabrian arc and the other is Mefite d'Ansanto moffete, one of the largest non-volcanic CO_2 emission in the world and located in Irpinia area, in the southern Apennines. The seismicity in the eastern sector of the Pollino range is very low except for a deep (>20km) earthquake swarm which started in the middle of September 2017 and lasted for some weeks with events up to Ml=2.7. The Mefite d'Ansanto site sits at the northern end of the northern fault activated by the M_w 6.8 Irpinia earthquake in 1980 and in the well-known thermal anomaly area of the Mt. Forcuso. A ~10km radius area around Mefite steems out for a very low seismicity rate compared with the high seismicity activity of this portion of Southern Apennines. In the frame of a long-term collaborative efforts made by the German Research Centre for Geoscience (GFZ) and the Istituto Nazionale di Geofisica e Vulcanologia (INGV) in the Pollino area a temporary network has been deployed to analyze the low earthquakes rate, the seismogenic structures and a possible signature of interaction with fluids redistribution within the crust. The temporary network consists of 3 seismic stations equipped with Trillium compact 120 sec. sensors and DCube digitizers using also CCube modules for real time data transmission. One single station with similar hardware has been used also to monitor the Mefite d'Ansanto in the Irpinia area with similar aim. Data is available from the GEOFON data centre, under network code YZ, and is embargoed until three years after the end of the experiments.
# 3
Passarelli, Luigi • Heryandoko, Nova • Muzli • Rasmid • Zimmer, Martin • (et. al.)
Abstract: The Halmahera island belongs to the North Moluccas province (Maluku Utara), Indonesia. This K-shaped island is located in the eastern part of the Moluccas Sea, the only active arc-arc collision complex on the Earth. The western arm of the K forms a volcanic arc due to the former subduction of the Moluccas Sea plate underneath Halmahera. The region is characterized by intense seismic activity at crustal, intermediate depth, and along the subducting plate. At crustal level the Halmahera seismicity along the two eastern arms of the K show strike-slip faulting style. In November 2015 a localized intense and energetic seismic activity started around Jailolo volcano in the West Halmahera Regency. The seismic sequence intermittently lasted until February 2016 and hundreds of events were felt by the population and several buildings were destroyed and damaged by the shaking. The largest shocks of the sequence have been located by global agencies (GEOFON and GCMT) showing normal faulting style. The temporal evolution of the seismicity seems to be more swarm-like type activity instead of mainshock-aftershock sequence. In spring 2016 a research project has been funded by the German's Humanitarian Aid program in collaboration with BMKG, Indonesia, with the goal of understanding the origin of the intense seismic activity and the related hazard. In summer 2016 we instrumented the area with a dense seismic network composed of 29 short period and 6 broad-band seismometers. The instruments deployment aims at characterizing the seismicity of the Jailolo region in relationship with the 2015-2016 seismic activity. The network will help to understand the seismo-tectonic of the area and the relation between seismicity and the volcanic activity at Jailolo volcano and possible link with the 2015-2016 swarm. Should the seismic activity intensify as in November 2015, we can record it and narrow down the underlying physical mechanisms. Waveform data are available from the GEOFON data centre, under network code 7G, and are embargoed until the end of 2021.
# 4
Roessler, Dirk • Passarelli, Luigi • Govoni, Aladino • Bautz, Ralf • Dahm, Torsten • (et. al.)
Abstract: The temporary Extended Pollino Seismic Experiment (FDSN network code Y4) monitored the earthquake swarm in the Pollino Range region, Italy, between September 2014 and April 2015. The experiment followed the Pollino Seismic Experiment, 2012-2014 (network code: 4A) [1] in the same area, further enhancing the detection and analysis capabilities there. It was part of a collaborative effort made by the German Research Centre for Geoscience (GFZ) and the Istituto Nazionale di Geofisica e Vulcanologia (INGV) within the CCMP-Pompei, FEFI and NERA projects. The Pollino Range region is located at the transition from the Southern Apennines chain to the Calabrian arc. Striking a volume of about 20x20x15 km, the swarm started in October 2010, culminated in a Mw=5.2 on 25 October 2012 and has continued since with a variable rate of activity. The area represents a seismic gap as there are no documented historical M>6 earthquakes during the last thousand years. The tectonic structures of the area are poorly known. The Y4 network consisted of 19 stations including 14 broadband and five short-period instruments. All instruments were provided by the Geophysical Instrument Pool Potsdam (GIPP) and the CCMP-Pompei project at GFZ and INGV. They were complemented by another four temporary IV stations installed by INGV. The short-period stations had Mark L-4C3D sensors with EDR digitizers. The broadband stations were equipped with STS2.5 seismometers and RefTek RT130S digitizers or Güralp CMG-ESP or Güralp CMG-40T seismometers and EDR digitizers. Eleven broadband (CSA0 to CSA10) were installed in a small-aperture detection array in the west of the range. The other 8 stations (broadband: CSB, CSE, CSD0 and short period: CSF, CSG, CSH, CSI, CSK) formed a network in the swarm area. The array and the network stations recorded in continuous mode at 200 Hz. The sensors were buried in the ground at 0.5 m depth except for CSB, CSE and CSD0 which were installed on the surface. High-precision station coordinates were obtained by using differential GPS measurements. The data have been used to analyze the earthquakes and seismogenetic structures and to discern the characteristics of the swarm sequence. Waveform data will be fully open after April 2017. [1] Pollino Seismic Experiment, 2012-2014, doi:10.14470/9N904956
# 5
Cesca, Simone • López Comino, José Ángel • Kühn, Daniela • Dahm, Torsten
Abstract: A temporary installation has been realized in the Netherlands, in the region of the Groningen gas field. The objective of this installation is to test the usage of a conventional array layout for detection of microseismicity. The region of the Groningen gas field is an excellent test ground, since the operating company NAM (Nederlandse Aardolie Maatschappij) installed a multitude of shallow borehole stations from 2014 to 2017, of which 65 – in addition to the already existing shallow borehole stations installed by KNMI (Koninklijk Nederlands Meteorologisch Instituut) – were already online during the time of measurement, thus ensuring an earthquake catalogue that is complete down to low magnitudes during the time of array installation. The site for the installation was decided together with local parties involved in the seismicity monitoring, i.e. KNMI and NAM, and was located close to the village of Wittewierum. Stations were installed from the 12th of July 2016 to the 29th of August 2016 (49 days). The array was composed of 9 stations. The array was constructed in three concentric rings of 75 m, 150 m and 225 m diameter including a central station, but the geometry had to be adapted to the local conditions. Each station consisted of a broadband sensor (Trillium 120 s), an acquisition system (CUBE datalogger), a battery, and a GPS antenna. The entire system was installed at ~1 m depth (apart from GPS and transmission antennas), requiring only the digging of shallow holes, one for the installation of a thin concrete plate and the sensor, another one for a box containing the remaining instrumentation. The array stations recorded continuously with little outages; only station WAR1 stopped recording on the 22nd of August and station WAR7 stopped recording from 20th to 22nd of August. Waveform data is available from the GEOFON data centre, under network code 1C, and is fully open.
# 6
Cesca, Simone • Sobiesiak, Monika • Tassara, Arturo • Olcay, Manuel • Günther, Erwin • (et. al.)
Abstract: The Iquique Local Network (ILN), a temporal network of broadband and short period seismic stations has been operating in Northern Chile since 2009. The aim of this installation was to locally densify the permanent seismic installation of the Integrated Plate Boundary Observatory in Chile (IPOC), with the main goal to decrease the magnitude of detected earthquake, to improve the hypocentral location accuracy, to allow a more accurate investigation of seismic source parameters, and to analyse proposed seismogenic structures of the Northern Chile seismic gap. The network setup evolved with time, with different geometries at different installation phases, aiming to study different seismicity features. In the first phase, started in 2009 and operational since 2010 until autumn 2013, the network had a sparse configuration, targeting a broad region extending from 19.5° S in the North to approximately 21.3° S South of Iquique. In the following stage, operational until fall 2017, most broadband stations were rearranged into a small aperture seismic array (PicArray) close to the village of Pica, to monitor with array techniques the shallow seismicity at the plate interfacer, intermediate and deep focus seismicity. Waveform data are available from the GEOFON data centre, under network code IQ, and arefully open.
# 7
Passarelli, Luigi • Roessler, Dirk • Aladino, Govoni • Maccaferri, Francesco • Moretti, Milena • (et. al.)
Abstract: The temporary Pollino Seismic Experiment, FDSN network code 4A, monitored the earthquake swarm in the Pollino Range region, Italy, between November 2012 and September 2014. The region is located at the transition from the Southern Apennines chain to the Calabrian arc. Striking a volume of about 20x20x15 km, the swarm started in October 2010, culminated in an Mw=5.2 event on 25 October 2012, and has continued since with a variable rate of activity. The area represents a seismic gap as there are no documented historical M>6 earthquakes during the last thousand years. The tectonic structures of the area are poorly known. The experiment was part of a collaborative effort made by the German Research Centre for Geosciences (GFZ) and the Istituto Nazionale di Geofisica e Vulcanologia (INGV) within the framework of the NERA and CCMP-Pompei projects. The 4A network consisted of 9 stations including 6 short-period and 3 broadband instruments, provided by GFZ. The permanent seismic network was complemented by the 9 GFZ stations and 5 IV stations temporarily installed by INGV. The short-period stations had Mark L-4C3D sensors with EDL digitizers. The broadband stations were equipped with STS2.5 seismometers and RefTek RT130S digitizers. Five short period and one broadband (CSA0 to CSA5) were installed in a small-aperture array in the west of the range. The other three stations (broadband: CSB, CSC and short period: CSD) were installed around the swarm area. The array and the network stations recorded in continuous mode at 200 Hz and at 100 Hz, respectively. The sensors were buried in the ground at 0.5 m depth except for CSB and CSD which were installed on the surface. High-precision station coordinates were obtained by using differential GPS measurements. The data have been used to analyze the earthquakes and seismogenetic structures and to discern the characteristics of the swarm sequence.
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