OR/18/029 Achievements
| Baptie, B. 2018. Earthquake seismology 2017/2018. British Geological Survey Internal Report, OR/18/029. |
Network performance
The network contains 44 broadband sensors with 24-bit acquisition which provide real-time data from across the UK. Significant faults were rapidly identified and remedied. Data completeness is high. A new strong motion alarm system was installed at Hunterston Nuclear Power station.
The network currently consists of 44 broadband sensors, 32 strong motion sensors and 6 short period sensors. In the last year the station MCD in Moray was upgraded with a broadband sensor and 24-bit data acquisition. A new strong motion alarm system was installed at Hunterston Nuclear Power station. Short period stations in old Moray and Galloway sub-networks were removed from service. Continuous data from all stations are transmitted in real-time to Edinburgh, where they are used for analysis and archived.
Two new stations operated by the AWE Blacknest and the Dublin Institute of Advanced Studies in Dover, Kent, and County Louth, Ireland, respectively, have been incorporated into our near real-time processing to improve our detection capability.
We are now using automated software processes to identify equipment faults rapidly. These include both gross errors such as data gaps or failures in timing, as well as indicators such as low voltages or high levels of tilt. These routines run on a daily, weekly and monthly basis to allow the aggregate effects of small but repetitive faults to be identified.
In 2017/18 around 150 separate significant faults were identified using these methods. The bulk of these faults were dealt with either remotely, or with the help of a network of local contacts. However, 61 stations required a visit by field section staff. 33 of these were to UKArray sites (see ‘map’ in Network development). To improve efficiency we combine multiple site visits into a single trip, and, if appropriate, use lone working.
During the year, 234 person days were spent on fieldwork, with 105 days spent on maintenance of permanent monitoring stations and 91 days on fieldwork associated with the UKArray experiment or the Department for Business, Energy and Industrial Strategy (BEIS) Environmental Baseline Monitoring project in the Vale of Pickering and the Fylde Peninsula. An additional 38 days were spent on site specific monitoring.
Continuous data from all our stations are archived and the completeness of these data can be easily checked to gain an accurate picture of network performance. For 2017–2018, data are more than 95% complete 79% of the time, 90% complete 89% of the time and 85% complete 93% of the time, which is a slight improvement on the previous year when data was 85% complete for more than 90% of stations and more than 90% complete for over 86% of stations.
The worst performing broadband stations were OLDB, Oldbury (75%) and GAL1, Galloway (90%). In the case of Oldbury much of the loss of data resulted because we were unable to access the site for a period of time. This was resolved in July 2017. Loss of data at GAL1 resulted from equipment failure that was concurrent with communications failures.
In addition, fewer than two stations were down at the same time 62% of the time and less than four down 99% of the time. A snapshot of the impact that this has on the overall detection capability of the network can be obtained by calculating detection capability maps with and without the stations that were down at any time. For example, in December 2017, two stations, MONM and RSBS were down at the same time. This does not have a significant effect on overall detection capability.
Network development
We are deploying sensors across the north of England as part of two projects: UKArray and Environmental Baseline Monitoring. Our aim is to provide improved earthquake catalogues, new, detailed models of the Earth’s crust under the UK, high resolution images of active fault zones and near real-time information about both natural and man-made seismicity.
In 2015, BGS received over £500 000 from the Natural Environment Research Council (NERC) to purchase forty seismic sensors that could be deployed as an array at different locations across the UK, for a project called UKArray. The project is supported by the universities of Bristol, Edinburgh, Leicester and Liverpool. Our aim is to provide new, detailed models of the Earth’s crust under the UK, high resolution images of active fault zones, and near real-time information about both natural and man-made seismic activity including the low magnitude earthquakes commonly associated with industrial activity. The data will also be used to answer fundamental scientific questions about the shallow and deep Earth and to address important issues relating to the future use of the Earth’s sub-surface both as a source for sustainable energy and as a means of energy and waste storage.
In addition, we have installed a dense network of sensors in the Vale of Pickering, North Yorkshire (Ward et al., 2017[1]) for an environmental baseline monitoring project that started in 2015 and is funded by the Department for Business, Energy and Industrial Strategy (BEIS). The aim of this project is to collect data that will allow reliable characterisation of baseline levels of the natural seismic activity in the region. This will help discriminate between any natural seismicity and induced seismicity related to future shale gas exploration and production. It will also help to better understand the hazard and mitigate the risk of seismic activity induced by such industrial activities.
In 2017/2018, we installed eight new UKArray temporary stations, giving a total of 34 stations across the North of England. We plan to install two more stations in 2018/2019.
Continuous data from all installed stations are being transmitted in real-time to the BGS offices in Edinburgh and have been incorporated in the data acquisition and processing work flows used for the permanent UK network of real-time seismic stations operated by BGS. A number of detection algorithms are applied to the data in the region to detect possible events.
Information dissemination
It is a requirement of the Information Service that objective data and information be distributed rapidly and effectively after an event. Customer Group members have received notification by e-mail whenever an event was felt or heard by more than two individuals.
Notifications were issued for 24 UK events within the reporting period. Notifications for all local earthquakes were issued to Customer Group members within two hours of a member of the 24-hour on-call team being notified. The alerts include earthquake parameters, reports from members of the public, damage and background information. Seventeen of the alerts were for earthquakes on mainland Britain and a further five were for earthquakes offshore in the waters around the British Isles. The two remaining alerts were for sonic events. No enquiries were received from Nuclear Power Stations in the period April 2017 to March 2018.
We continue to update the Seismology web pages. These web pages are directly linked to our earthquake database providing near real-time lists of significant earthquake activity, together with automatically generated pages for each event.
Our web pages also incorporate our automatic macroseismic processing system, which remains a key part of our response to felt events and is used to produce macroseismic maps for the seismology web pages that are updated in near real-time as data are contributed. We received 7,811 replies following the South Wales earthquake on 17 February 2018 (4.6 ML), 353 replies following the magnitude 4.0 ML Moidart earthquake on 4 August 2017 and 110 replies following a magnitude 3.4 ML earthquake near Cockermouth, Cumbria on 28 February 2018.
Updates were circulated to Customer Group members following the South Wales earthquake on 17 February, as new information became available. BGS Open Reports on the South Wales (Baptie et al, 2018[2]) and the Moidart earthquakes (Baptie et al, 2017[3]) were also issued.
Communicating our science
An important part of the BGS mission is to provide accurate, impartial information in a timely fashion to our stakeholders, the public and the media. We promote understanding of Earth Sciences by engaging with schools through the UK School Seismology project and by creating dynamic web pages with background information and topical content.
BGS staff, including Davie Galloway and Heiko Buxel from the Seismology Team, took part in the ‘BGS Auroras and Earthquakes’ Open Day at Lerwick Observatory, Shetland Islands on 30 June and 1 July 2017. Lerwick Observatory has been running for 95 years as a geomagnetic observatory but it is also home to seismological instruments measuring earthquakes. While the seismologists were on the Island, an earthquake, with a magnitude of 4.7 ML, occurred at 13:33 UTC on Friday afternoon (30 June) in the Central North Sea region, approximately 215 km SE of Lerwick. It was felt across the Shetland Islands and generated a huge amount of interest at the Open Day.
Heiko also represented the Seismology Team at the first BGS Open Day to be held at the Lyell Centre, Edinburgh (the new home of BGS in Scotland) in September 2017. The event gave members of the public the chance to find out about the research at the Lyell Centre including geomagnetism, seismology and volcanology.
Davie Galloway and David Hawthorn from the Seismology Team took part in the NERC showcase event ‘UnEarthed — Explore the world at your feet’, hosted at Dynamic Earth, Edinburgh, in November.
With over 7,000 people, including 20 invited schools, visiting the many BGS displays, it was a massive public engagement for seismology and BGS.
In January, Davie Galloway gave a presentation on earthquakes and volcanoes to pupils from George Heriots School in Edinburgh as part of their natural disasters school project curriculum. Many of the pupils also attended the BGS Unearthed showcase event at Dynamic Earth.
Davie Galloway attended a two day workshop in February 2018 at the Geological Society London on ‘Educational and Citizen Seismology’. The workshop was organised by Paul Denton, who leads the BGS School Seismology project, and brought together key practitioners in educational and citizen seismology from across the UK, Europe and worldwide. The event was part of the Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe (SERA) project, an EU-funded Horizon 2020-supported programme that involves 31 partners from 16 European countries. The SERA project started in May 2017 and will last for three years. BGS is leading WP3 Networking Seismo@school outreach programs. The work package includes the following tasks: workshops in educational seismology; resource collation and publication; coordination and interaction with the wider community; science with Seismo@school; integration of citizen seismology and educational seismology.
Brian Baptie gave an invited talk to the Edinburgh Geological Society in March on the subject ‘Is earthquake activity increasing?’ Destructive earthquakes often lead to speculation that earthquake activity is increasing, but is there really any hard evidence to support this? The lecture drew on earthquake statistics and geophysics to discuss this question with notable examples of how earthquake activity rates can change.
BGS remains a principal point of contact for the public and the media for information on earthquakes and seismicity, both in the UK and overseas. During 2017–2018, at least 820 enquiries were answered. These were all logged using the BGS enquiries tracking database. Many of these were from the media, which often led to TV and radio interviews, particularly after significant earthquakes.
The seismology web site continues to be widely accessed, with over 2.5 million visitors logged in the year (over 15 million hits). Over twice the average monthly number of visitors were recorded in February 2018 following the South Wales earthquake.
The Seismology web pages are intended to provide earthquake information to the general public as quickly as possible. Earthquake lists, maps and specific pages are generated and updated automatically whenever a new event is entered in our database or when the parameters for an existing event are modified. We also have a database search page that allows users to search our database for basic earthquake parameters within a given geographic or magnitude range. We have also continued to provide displays of real-time data from most of our seismic stations that allow users to check activity or look for specific events. In addition, we continue to add event-specific content for significant earthquakes in the UK and around the world.
Collaboration and data exchange
Data from the seismograph network are freely available for academic use and we have continued to collaborate with researchers at academic institutes within the UK throughout the past year, as well as exchanging data with European and world agencies.
Margarita Segou is PI of the project ‘The central Apennines earthquake cascade under a new microscope’, that successfully received funding from NSFGEO-NERC (NE/R000794/1) in 2017 with Brian Baptie as the Co-I. The project aims to improve understanding of the evolution of long lasting earthquake sequences, such as the Central Apennines earthquake sequence (2016/2017), and to develop tools that can support informed decision-making in the future.
The project is an ambitious international collaboration with partners from UK (BGS, University of Edinburgh, Bristol), USA (University of Stanford, US Geological Survey, Lamont-Doherty Observatory Columbia University) and Italy (INGV). The kick-off meeting for the NERC-NSF project was held at the Istituto Nazionale Geofisica E Vulcanologia (INGV), Rome at the end of January.
In February 2018, Margarita Segou visited the Disaster Prevention Research Institute in Kyoto (Japan) to work with Professor Jim Mori on an investigation of earthquake triggering and the 2016 Kumamoto sequence. The visit was funded by a RCUK-DPRI Kyoto Research Grant.
Margarita and other BGS staff are also participating in a large consortium focused on the multi-hazard aspects of risk modelling. The aim is to implement innovative science together with state of the art instrument deployment in an effort to provide excellent science serving risk reduction practices worldwide.
The NERC funded Earthquakes without Frontiers (EwF) project has been extended for another year and Susanne Sargeant and Ilaria Mosca are continuing to work within a partnership that includes researchers from a number of UK universities (Cambridge, Oxford and Durham among others) and the Overseas Development Institute. EwF is a transdisciplinary research project that aims to increase resilience to earthquakes and landslides in the Alpine-Himalayan Belt, focussing on Kazakhstan, Nepal, Bihar in northern India, and NE China.
Susanne and Ilaria have continued to work on the development of ground motion and seismic hazard models that can be used by stakeholders engaged in policy making and community-based risk reduction activities.
Susanne is also working with researchers from the University of Edinburgh, University College London and Kings College London on a multi-disciplinary research project designed to improve the assessment of time-independent and time-dependent seismic hazard in Yunnan and Sichuan in China, and how this kind of information is used by decision makers.
Richard Luckett and Brian Baptie are working with researchers at the University of Bristol on induced seismicity. Some of the results of this collaboration were published by Verdon et al (2017)[4].
Richard and Brian are also working with physicists at National Physical Laboratory on the use of submarine optical cables for earthquake detection.
Brian Baptie is currently a Co-I of a new project, REMIS (Reliable Earthquake Magnitudes for Induced Seismicity). The project is funded by NERC (NE/R001154/1) and is a collaboration with the Universities of Leeds and Edinburgh. The project aims to determine interlinked probability density functions of earthquake locations, magnitudes, and seismic velocities in the subsurface using a non-linear Bayesian approach.
BGS, along with the universities of Birmingham, Bristol, Manchester and York and partners from Public Health England (PHE), is conducting an independent environmental baseline monitoring programme in the Vale of Pickering, North Yorkshire.
BGS data are exchanged with other agencies to help improve source parameters for regional and global earthquakes. Phase data are distributed to the (EMSC) to assist with relocation of regional earthquakes and rapid determination of source parameters. Phase data for global earthquakes are sent to both the National Earthquake Information Centre (NEIC) at the USGS and the International Seismological Centre (ISC). This year, data from 424 seismic events were sent. Data from the BGS broadband stations are transmitted to both ORFEUS, the regional data centre for broadband data, and IRIS (Incorporated Research in Seismology), the leading global data centre for waveform data, in near real-time.
References
- ↑ Ward, R S, Smedley, P S, Allen, G, Baptie, B J, Daraktchieva, Z, Horleston, A, Jones, D G, Jordan, C J, Lewis, A, Lowry, D, Purvis, R M, and Rivett, M O. 2017. Environmental Baseline Monitoring Project. Phase II, final report. British Geological Survey, OR/17/049, 163pp.
- ↑ Baptie, B, Ford, G, and Galloway, D. 2018. The South Wales earthquake of 17 February 2018. British Geological Survey Open Report, OR/18/019.
- ↑ Baptie, B, Ford, G, and Galloway, D. 2017. The Moidart earthquakes of 4 August 2017. British Geological Survey Open Report, OR/17/062.
- ↑ Verdon, J P, Kendall, J M, Butcher, A, Luckett, R, and Baptie, B. 2017. Seismicity induced by longwall coal mining at the Thoresby Colliery, Nottinghamshire, UK. Geophysical Journal International, 212 (2).