SM2.3

ORFEUS (Observatories and Research Facilities for European Seismology, http://orfeus-eu.org/) is a non-profit organization founded in 1986 with the chief goal to promote seismology in the Euro-Mediterranean area through the collection, archival and distribution of seismic waveform data, metadata, and closely related services and products. ORFEUS also supports the coordination and implementation of large scale community initiatives and experiments in observational seismology, and provides community support through software and travel grants, editorial initiatives and training activities. ORFEUS data and services are collected or developed at national level by more than 60 contributing Institutions (see https://orfeus-eu.org/organization/corporate_founders/ and https://orfeus-eu.org/organization/participation/) in the greater European region, and further developed, integrated, standardized, homogenized and promoted through ORFEUS. Within EPOS, ORFEUS represents the seismological waveform services as one of three sub-domains of EPOS Seismology. ORFEUS data and services are open, FAIR, and accompanied by clear policies and licensing information. Two Service Management Committees (SMCs) are established within ORFEUS, devoted to managing, operating and developing (with the support of one or more Infrastructure Development Groups): (i) the European Integrated waveform Data Archive (EIDA; https://www.orfeus-eu.org/data/eida/); and (ii) the European Strong-Motion databases (SM; https://www.orfeus-eu.org/data/strong/). A new SMC is being formed to represent the community of European mobile instrument pools, including also amphibian instrumentation. Products and services for computational seismologists are also possible candidates for integration in the ORFEUS domain. Overall, ORFEUS services currently provide access to waveforms acquired by ~ 16,000 stations, including dense temporary experiments, with strong emphasis on open, high-quality data. Contributing to ORFEUS data archives means benefitting from long-term archival, state-of-the-art quality control, improved access, increased usage, and community participation. Access to data and products is ensured through state-of-the-art information and communication technologies, with strong emphasis on web services that allow automated user access to data gathered and/or distributed by the various ORFEUS institutions (see ​​https://orfeus-eu.org/data/eida/webservices/ and https://esm-db.eu/#/data_and_services/web_services). Particular attention is paid to acknowledging the crucial role played by data providers, who are part of the ORFEUS community. ORFEUS strongly encourages the use of international network codes, seismic network digital object identifiers, and full network citations. All ORFEUS services are developed in coordination with EPOS and are largely integrated in the EPOS Data Access Portal (https://www.ics-c.epos-eu.org/). Documentation on ORFEUS data and services is provided on the ORFEUS website and is complemented by a large archive of ORFEUS community workshops and seminars / webinars  (https://orfeus-eu.org/other/workshops/). ORFEUS data and services are assessed and improved with the help of technical and scientific feedback from a User Advisory Group (UAG), which comprises European Earth scientists with expertise on a broad range of observational seismology topics. ORFEUS is a key participant in EC-funded projects and collaborates with global and international organizations with similar scope, like the FDSN (https://fdsn.org/), IRIS (https://www.iris.edu/), and COSMOS (https://strongmotion.org/).

How to cite: Cauzzi, C., Bieńkowski, J., Crawford, W., Custódio, S., D'Amico, S., Evangelidis, C., Guéguen, P., Haberland, C., Haslinger, F., Lanzano, G., Ottemöller, L., Rondenay, S., Sleeman, R., and Strollo, A.: Coordinating Access to Seismic Waveform Data in Europe: Overview of ORFEUS Activities, Services and Products, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3954, https://doi.org/10.5194/egusphere-egu22-3954, 2022.

When monitoring seismicity, detection thresholds for magnitude and location accuracy for epicentres are basic quality factors used. However, these factors can be estimated in numerous ways, depending on available data, the tasks the network is built for and customer/legal guidelines.

In this work, we focus on location quality. We analyse location quality for the area of Austria and a smaller project within. For this purpose, we calculate location errors with NLLoc (Lomax, et al. 2009) for Austria and compare them with location errors automatically computed for each earthquake located by the Austrian Seismological Servicewithin the last 2 years. Additionally, we use the quality parameters given in Bondar, et al. (2004) for further analysis.

How to cite: Apoloner, M.-T., Horn, N., and Hausmann, H.: Review of earthquake location quality since 2020 for Austria, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4410, https://doi.org/10.5194/egusphere-egu22-4410, 2022.

The Guadiana Menor River, included in the Guadalquivir foreland basin, at the northern border of the Betic Cordillera, has suffered in the last decade some low to moderate magnitude seismic series. For instance, the so called 2012-2013 Sabiote-Torreperogil seismic sequence, 1 to 5 km deep, being the biggest recorded event a m_bLg 3.9 earthquake, and the so called 2016-2018 Jódar-Peal de Becerro seismic series, less than 2 km and 9 to 13 km deep, 20 km southeast of the previous one, being a m_bLg 4.1 event the greatest recorded magnitude. In both cases, seismic series show focal mechanism solutions mostly with strike-slip and some dip-slip and NW-SE compression with no clear tectonic features at surface, due to the sedimentary infill. The Spanish Instituto Geográfico Nacional (IGN) national seismic network recorded in the last years, mainly in the region of the 2016-2018 seismic sequence, some low magnitude earthquakes, showing that the fault that hosted these events continues to be active.

This was the main reason to develop a little local seismic network in the region, designed with the aim to study this persistent seismicity in terms of locations and focal mechanism solutions when there could be available data. It is equipped with six triaxial broadband sensors specifically deployed for this purpose, and also sharing data coming from a near IGN seismic station in the region. The seven seismic stations present as uniform azimuthal distribution as possible around the seismicity, being the nearest station less than 5 km from the seismicity area, and the farthest about 30 km away. Anyway, the seismic network spatial distribution has been conditioned for the fact that they are not permanent housing stations, requiring electric power. Most of the seismic stations are recording data from September 2021.

Real-time records are shared with the Spanish IGN seismic network in order to improve regional locations. Until now, several low magnitude earthquakes, below the perceptibility level of the national seismic network, have been located. In addition, focal mechanisms have been computed for some low magnitude events (~ m_bLg 2.0), congruent with strike-slip solutions.

How to cite: Garrido, J., Peláez, J. A., Henares, J., and Marín, C.: Deployment of a local seismic network around the northern Guadiana Menor River (Betic Cordillera, Spain), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2468, https://doi.org/10.5194/egusphere-egu22-2468, 2022.

The Lesser Antilles volcanic arc on the eastern boundary of the Caribbean Plate is part of the Caribbean subduction zone. The subduction process is responsible for the formation of 16 volcanoes in this arc, forming islands like Saba and St. Eustatius in the Caribbean Netherlands. KNMI deploys a monitoring network on these islands consisting of seismometers and GNSS stations. The seismic network is built with broadband seismometers to monitor seismic signals from (regional) earthquakes and from volcano related processes at Saba and St. Eustatius. We use local infrastructure as well as stand-alone VSAT technology to transmit seismic data in near real-time to KNMI. Data are forwarded in real-time to the Pacific Tsunami Warning Center (PWTC). Waveforms are openly available to the research community through ORFEUS/EIDA, and through EPOS-NL, a Dutch national research infrastructure for solid Earth science that integrates large-scale geophysical facilities in the Netherlands.

Volcanoes Mt. Scenery (Saba) and The Quill (St. Eustatius) are active but quiescent. Volcanic earthquakes may occur at different depths and are caused by various processes in a volcano. Each type of volcanic earthquake exposes differences in features in the waveform data, like frequency content, waveform envelope, duration, statistical parameters and type of onset. We are building a monitoring system based on various tools and techniques, like a) SeisComP3 for detecting and locating regional tectonic earthquakes, b) a coincidence trigger to detect small, local (volcanic) earthquakes, c) covariance matrix analysis to identify coherent signals across the network, d) seismic interferometry to monitor seismic velocity changes in the subsurface of the volcanoes and e) data quality monitoring  to ensure high quality of data.

We provide an overview of the seismic network, the infrastructure, the availability of data through EPOS-NL and the implementation of the various monitoring techniques.

How to cite: Sleeman, R. and de Zeeuw-van Dalfsen, E.: A volcano seismic monitoring network in the Caribbean Netherlands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-13025, https://doi.org/10.5194/egusphere-egu22-13025, 2022.

Livingston Island is one of the eleven islands of the South Shetland Archipelago which is separated from the Antarctic Peninsula by Bransfield Strait and from South America by the Drake Passage. In 1988 in the eastern part of the Island, the Bulgarian Antarctic Base “St. Kliment Ohridski” (BAB) was established. The Base works during the austral summers and accommodates scientists from different branches of the science. The first Bulgarian Polar Seismic Station LIVV was set in operation in 2014 as a seasonal station operating during the regular Antarctic expeditions. In 2019, the station was rebuilt on a new site one kilometer far from BAB. The seismological equipment was installed on a bedrock outcrop at the base of a hill. The equipment consists of broadband seismometer Guralp CMG40T with 30 s to 50 Hz flat velocity response and one short period 4.5 Hz Geophone. Thermo-insulation covers are mounted over the both sensors to ensure stable environment. The digitizer Reftek DAS-130/6 and the solar panel controller are installed close to the sensors in a thermo insulated box. The station is powered by a battery and solar panel. A GPS receiver ensures time synchronization. At the end of the XXVIII Bulgarian Antarctic expedition in March of 2020, the seismic station LIVV was set as permanent year-round operational Antarctic station. Using the recorded state of the health information and the registered seismic data, we analyzed the performance of the station LIVV. For the two years of permanent deployment, the seismic equipment works stable. The battery has retained its working capacity despite low temperatures and high humidity. There are interruptions in the recording when the sunlight is not high enough to charge the battery above 12V. After restoring the power supply, the equipment immediately is switched on in the normal registration mode. The temperature inside of the thermal box hasn’t dropped below 6⁰ C and the electronic components have worked in an optimal environment. The cycle operational mode of the GPS receiver is suitable set to ensure high accuracy time. The analysis of the recorded seismic data shows that the mode value of the ambient seismic noise, for longer periods greater than 1s, is 10-20dB below High Noise Model and for the shorter periods below 1 s it falls to -140dB. The noise level suggests good recording capabilities of the station especially in the short periods. This is proven by the large number of recorded earthquakes and events in the ice cover of the Livingston Island during the two years exploitation period. The analysis of the performance of the seismic station LIVV shows that the station is built on a stable foundation (bedrock), and the provided thermal insulation creates an optimal mode of operation of the seismic equipment. With an uninterruptible power supply, the seismic station will operate reliably and without interruption throughout the year, and the quality of the recorded data will be high enough to analyze the seismicity in the region and the behavior of the ice sheet of the Island.

How to cite: Dimitrova, L., Georgieva, G., Dragomirov, D., and Buchekchiev, V.: Two years of permanent deployment of seismic station LIVV, Antarctica, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8418, https://doi.org/10.5194/egusphere-egu22-8418, 2022.

Existing regional and EEW networks can be improved in data quality, providing more stations with unclipped continuous waveform observations and a uniform magnitude of completeness (Mc).  This is possible using upgraded deeper sensor emplacements and new instrumentation, based on a current understanding of system noise and updated equipment available today.  Station density is increasing with the EEW buildout, with a focus on minimizing latency, which also presents an opportunity to improve data quality for weak motion.  Mc and signal-to-noise ratio across the seismic and geodetic spectrum will be important for future OEF challenges and for hazard and science efforts such as 4D studies and the high resolution geophysical imaging of deep Earth structure.  Recent development of network Mc simulation code (Wilson et al., 2021) can be used to plan new networks, or infill stations to economically upgrade existing networks to these new best practices.  

An instrument system that provides high-gain weak motion data in precise alignment with strong motion data allows combined processing to create a seamless data set with maximum dynamic range.  The Nanometrics Cascadia 120 Slim Posthole has been designed to meet these requirements. Both weak and strong motion sensors are integrated in a single case which enables lowest system noise, unclipped observations, and precise coherence of signals between the weak and strong motion channels.  Cascadia 120 Slim and Cascadia Compact are deployed in networks now and we will present data showing the noise floor for weak motion, a seamless transition to strong motion, and high coherence between the two sensors for mid-sized events.

Authors: Valarie Hamilton, Geoffrey Bainbridge, Tim Parker, Daniela Wuthrich

How to cite: Hamilton, V., Parker, T., Bainbridge, G., and Wuthrich, D.: Cascadia 120 Slim Posthole: A Combined Strong and Weak Motion Sensor for Early Warning and Regional Networks, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10500, https://doi.org/10.5194/egusphere-egu22-10500, 2022.

An important consideration in selecting instrumentation to support the undertaking of portable seismic campaigns has been the costs associated with physical attributes, namely Size, Weight, and Power.  A more holistic approach would be to examine the overall campaign lifecycle and the phases which have the greatest impact on science outcomes. In this regard, some of the key success factors are the decisions made during the deployment planning phase that includes network size, station geolocation, instrumentation and sensor choices. Often overlooked is the data management problem associated with ensuring that the most up-to-date information associated with the plan is communicated to everyone who needs it. Further, another often overlooked aspect is the accurate tracking and reporting of what actually is deployed in the field relative to the plan, since such deviations inevitably occur.

The Pegasus Data Acquisition System is an ecosystem of hardware and software components for portable seismic monitoring that fundamentally transforms how seismic campaigns are conducted. This integrated ecosystem-based approach to seismic data acquisition ensures that campaigns are easy to plan, execute and achieve superb outcome certainty and cost-efficiency. A range of Pegasus models have been designed specifically to support Portable, Polar and OBS campaigns. Seamlessly integrated workflows address all aspects of the campaign lifecycle from pre-planning to pre-configured deployments, harvesting ready-to-use complete data sets, configuration distribution to field technicians and automatically generated metadata.

Authors: David Easton, Michael Perlin, Sylvain Pigeon, Tim Parker, Valarie Hamilton

How to cite: Easton, D.: Transforming Portable Seismic Data Acquisition: From Experiment Design to Publishing, an Ecosystem Approach, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10561, https://doi.org/10.5194/egusphere-egu22-10561, 2022.