Observatories and Research Facilities for EUropean Seismology
Volume 3, no 1 June 2001 Orfeus Newsletter


SEIS-UK - A New Centre for Seismic Equipment and Data Management in the UK

Alex Brisbourne1, Paul Denton1 and SEIS-UK2
1SEIS-UK, Department of Geology, University of Leicester, Leicester, LE1 7RH. www.le.ac.uk/seis-uk/
2 SEIS-UK - P.K.H. Maguire, R.W. England, C.J. Ebinger, C.M.R. Fowler, G.W. Stuart, R.S. White, K. Priestley (A Consortium from the Universities of Leicester, Royal Holloway London, Leeds and Cambridge); Executive Manager: Paul Denton; Seismologist: Alex Brisbourne; IT: Andy Myers

Introduction - Broadband Instrumentation - Short Period Instrumentation
Computing Facilities - Current Projects - Loans Procedure - References

Introduction

SEIS-UK (Seismic Equipment Infra-Structure in the U.K.) is a new facility to assist academic geoscientists to acquire and manage seismic data. SEIS-UK is funded by a Joint Infrastructure Fund (JIF) grant won by a consortium of four UK universities (Leicester, Cambridge, Royal Holloway College and Leeds). The facility provides the field equipment, computers and software necessary for experiments involving onshore recording of both controlled seismic sources and earthquakes. The facility is housed at the University of Leicester.

A total of 30 broadband and around 150 short period systems will be made available. Systems are being created to manage the total data path, from recording data at a field site to producing a dataset suitable for interpretation or archiving. SEIS-UK can provide computers and software for use on field projects which will enable the archiving of raw data onto tape in a rapid and efficient manner. For controlled source seismic experiments, SEGY record sections (either shot or receiver gathers) will be produced on tape or disk ready for reading into standard processing packages such as ProMAXTM. For natural source experiments (earthquake recording) data will be archived in SEED format, separated into "network day/week" volumes or "station month/year" volumes. These SEED volumes will then be suitable for immediate use via existing software routines or for permanent archiving.

It is the responsibility of the scientist running the experiment to provide all personnel and logistical costs required for experiments. The SEIS-UK team will only be able to provide assistance and training in procedures for the operators. It is required that all scientists provide a written report to the SEIS-UK committee on the scientific outcome of experiments involving these systems, including all publications arising from their use. Data must be released into the public domain within 3 years of the end of data acquisition.

Broadband Instrumentation

SEIS-UK can supply up to 30 Broadband Seismic Systems:
  • 10 x 120s Guralp GMG-3TD sensors
  • 20 x 30s Guralp CMG-40TD sensors
    • with integral 24bit digitiser
    • SAM data recorder with 9Gb SCSI disks
    • Siemens SM36 solar panels
    • GPS, cabling, spare disks, etc


Figure 1. An example of the Power Spectral Density of site noise achieved with a Guralp 40TD compared to the new low- and high-noise models. In this example, due to the site location characteristics, simple burial of the sensor was selected as the most suitable deployment method.

Pre-deployment training and advice can be provided regarding field methods. In-field assistance is also available.


Figure 2. Guralp 40TD and 3TD instruments undergoing a Huddle Test prior to the Cambridge University START experiment in the Tongariro National Park, North Island, New Zealand.

Short Period Instrumentation

Short period instrumentation will become available for controlled-source and passive experiments towards the end of 2001. SEIS-UK are in the process of acquiring around 150 x 1Hz sensors and very low power data recorders. Available short period instrumentation is currently undergoing evaluation by the consortium.

Computing Facilities

A complete data archiving facility is available in the UK
  • Sun Enterprise 220R rack mounted server with 2 processors and 2 Gb memory.
  • Sun T3 fibre-channel RAID disk array of 9 x 73 Gb disks.
  • Sun DLT8000 and DAT DDS4 autochanger tape drives
The facility also exists to produce archive-ready data sets in the field during the experiment. However, this can be carried out most easily at the data management centre in Leicester. For passive experiments,
  • PDCC software (IRIS) is used to produce dataless seed volumes, used in conjunction with miniSEED data
  • Full seed network-event volumes are derived from network-day volumes using weed and rdseed (IRIS)
SEIS-UK can provide full training in the use of PDCC software for the production of the dataless seed volumes. SEIS-UK aim to have the ability to maintain a permanent data archive through collaboration with both ORFEUS and the IRIS DMC.
The facility is freely available to all interested parties. The scope is not limited to data acquired using seismic equipment.

Current Projects

NEW ZEALAND - The Taupo Volcanic Zone is an excellent example of the initial stages of back-arc spreading in continental lithosphere. Data from broadband seismometers deployed across the TVZ will be used to study the change in geometry and velocity structure across the transition from near-zero to marked crustal extension. Tomographic imaging will provide information on the local crustal structure, and possibly allow imaging of pooled magma directly beneath the volcanoes (R.S. White, University of Cambridge).

NORTH ATLANTIC - The Icelandic plume has played a major role in the initial opening of the Atlantic; it is responsible for the excess crustal thickness forming Iceland and the Greenland-Iceland-Faeroes ridge; and it affects the bathymetry over much of the NE Atlantic. Surface waves for single and two-station paths across the NE Atlantic will be recorded. These data will provide information on the crust and upper-mantle S-wave structure of the plume, which is much more sensitive to the thermal structure than is the P-wave velocity structure (K. Priestley, University of Cambridge).

ETHIOPIA - Controlled source and passive seismic experiments will be undertaken to image the crust and upper mantle just prior to break-up in the northern Ethiopian Rift where the transition from continental rifting to incipient spreading is captured. It is a region where extensional velocities are low (4mm/yr), rift basins are asymmetric and bounded by steep border faults, and en echelon arrangement of the new magmatic segmentation shows little correlation with the older border fault pattern (P. Maguire, Leicester; C. Ebinger, M. Fowler, Royal Holloway London; G. Stuart, J.-M. Kendall, Leeds).


Figure 3. Location of UK and proposed US (Stanford University and the University of Texas, El Paso) normal incidence and wide angle profiles, and UK passive arrays.

Loans Procedure

Once the system has been commissioned applications will be welcomed from all interested academic groups to use the equipment and facilities.
  • The schedule of SEIS-UK equipment use will be posted on the SEIS-UK website and kept up to date.
  • Once a time slot has been identified (in discussion with the Executive Manager and the SEIS-UK Consortium) then a standard NERC Geophysical Equipment Pool equipment loan form should be filled out, identifying the equipment required as SEIS-UK items.
  • These applications will then be reviewed under the existing NERC GEP scientific review procedures before being passed on to the SEIS-UK committee for scheduling.
  • Existing NERC GEP procedures will then also be used for monitoring equipment performance and publications.

References

  • Brisbourne A., Denton P., Maguire P.K.H. and SEIS-UK, 2001. SEIS-UK - A new centre for seismic equipment and data management in the UK. 26th EGS conference, Nice, France.
  • Maguire P., Ebinger C., Fowler M., Stuart G., Kendall J-M. and SEIS-UK, 2000. Array Design to Study Crust and Upper Mantle Processes just Prior to Continental Break-up. AGU 2000 fall meeting, San Francisco, USA.
Further information is available on the SEIS-UK website at www.le.ac.uk/seis-uk/

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