On 15 October 2006, a large earthquake damaged both telescopes at Keck Observatory causing them to miss weeks of observation. Following this event, the observatory wanted to upgrade the structural support systems of both telescopes to reduce downtime during operational-level earthquakes and to endure survival-level earthquakes. SGH analyzed the Keck telescopes for seismic performance.
SGH performed a preliminary feasibility study for a new seismic restraint system. We recommended developing finite element models of the two telescopes to reliably estimate the seismic response of the telescopes and ensure all critical and high-value equipment, including instruments, would be protected during an earthquake. SGH developed finite element models of the Keck I and Keck II telescopes and performed the following analyses:
- Time history analyses of the two telescopes subjected to the recorded ground accelerations from the 2006 earthquake to compare with the observed damage
- Modal analyses of the two telescopes to compare the calculated natural frequencies to the measured frequencies obtained from the servo identification study performed by Keck Observatory
- Seismic response spectrum analyses of the two telescopes subjected to a survival-level earthquake
- Time history analyses of the two telescopes subjected to ground acceleration time histories for survival-level earthquakes