Construction of Seismic Vaults for the FLED
(Florida to Edmonton Array) Experiment

Overview | Construction Stages with Photos | Materials List | Contact Info


Temporary seismic vaults were constructed at 26 sites from Florida to Alberta. They were all installed near to AC power so that solar panels or wind generators were not needed. This part of North America often has clay soil which does not drain water well. Since the flatness of the terrain usually prohibits the installation of a drain into the vault, flooding is a significant possibility. In order to render the sites virtually flood-proof, we used an inverted barrel over the sensor within the vault. When this barrel is weigted down from the top, it acts like an old diver's bell jar. The air pressure inside the barrel will not let water enter from the bottom. We think this design could dramatically reduce the frequency of flooding for temporary deployments such as FLED.

Construction Stages with Photos

The design shown here works well with the STS-2 broadband seismometer, but it should work well with other similarly-sized instruments.

  1. Dig the hole.
  2. Cement pier at bottom of hole.
  3. Determine orientation of the pier.
  4. Orient and level the seismometer.
  5. Install outer barrel.
  6. Place styrafoam rose cones over sensor.
  7. Install inner barrel.
  8. Place weights over inner barrel.
  9. Check to see that sensor is working.
  10. Bury vault with left over dirt.
  11. View of the electronics box.
  12. Final view of the entire site.

Materials List

Quantity Item Distributor Cost
1 50-gal polyethylene drum (ID=22.5'') (blue) McMaster-Carr, part# 4319T911 $71.78
1 30-gal polyethylene drum (ID=18.5'') (white) McMaster-Carr, part# 4319T811 $50.48
1 Pro tuff bin (37'' x 21'' x 20'') (black) Contico, part# 3725 (available at The Home Depot with latch or Wal-Mart without latch) ~$49.00
2 styrafoam rose cones any hardware store ?
2 16-lb round concrete paver blocks (12'' diameter x 2'') any hardware store ?
6 38-lb square concrete paver blocks (16'' x 16'' x 2'') any hardware store ?
1 6-lb bucket of quick-setting cement (Quikrete or Rockite) any hardware store ?
1/2 sheet styrafoam board any hardware store ?
3-ft (more if installing drain) 2'' PVC pipe any hardware store ?

Mcmaster-Carr Supply Company
600 County Line Road
Elmhurst, IL 60126
tel: 630-833-0300
fax: 630-834-9427
(other locations on website)

Contico Manufacturing
305 Rock Industrial Park Drive
St. Louis, MO 63044
tel: 800-831-7077

Contact Information

If you have any questions or suggestions, please contact:

Michael Wysession
Department of Earth and Planetary Sciences
Box 1169
Washington University
St. Louis, MO 63130
tel: 314-935-5625
fax: 314-935-7361

Overview | Construction Stages with Photos | Materials List | Contact Info

This page last modified 06/20/01.