Environmental Engineering Reference
In-Depth Information
Geological risk at world class astronomical observatories
antonio eff-Darwich
Departamento Edafología y Geología, Universidad de La Laguna, Tenerife, Spain
Begona García-lorenzo
Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain
Jose a. Rodr
í
guez-losada
Departamento Edafología y Geología, Universidad de La Laguna, Tenerife, Spain
luis e. hernández
Area de Laboratorios y Calidad de la Construcción, Consejería de Obras Públicas y Transportes,
Tenerife, Spain
Julio de la nuez
Departamento Edafología y Geología, Universidad de La Laguna, Tenerife, Spain
carmen Romero-Ruiz
Departamento de Geografía, Universidad de La Laguna, Tenerife, Spain
aBsTRacT: Future large and extremely large ground-based telescopes will demand stable geological
settings. The world class astronomical observatories of el Teide (Tenerife, canary islands), Roque de los
Muchachos (la Palma, canary islands), Mauna kea (hawaii) and Paranal (chile) are in or closer to
volcanic environments, and hence the impact of volcanic activity has to be studied in detail. in this sense,
seismic activity, the extent of lava flows, eruptive clouds and ground deformation associated to volcanic/
tectonic activity have studied in terms of probabilistic risk analysis. This information might be essential in
ranking astronomical sites for emplacing future large telescope infrastructures.
1
inTRoDUcTion
astronomical observatories are vulnerable to
geological activity, hence it is necessary to consider
the impact on the telescope facilities, but also on sup-
porting facilities at the observatories and on local/
regional communication and infrastructures. in this
work, only direct hazards to telescopes have been
considered, in particular those affecting the struc-
tural design of telescopes, namely lava flows, vol-
canic ashfall and seismicity. The analysis was carried
out at four world-class observatories, namely Roque
de los Muchachos (la Palma, canary islands,
28.75°n, 17.89°e, 2400 m.a.s.l.), el Teide (Tenerife,
canary islands, 28.3°n, 16.51°e, 2380 m.a.s.l.),
Paranal (chile, 24.62°s, 70.4°e, 2620 m.a.s.l.) and
Mauna kea (hawaii, 19.82°n, 155.47°e, 4130
m.a.s.l.) and the candidate site of cerro Ventarrones
(chile, 24.35°ss, 70.2°e, 2200 m.a.s.l.). a common
methodology was used to characterize the geologi-
cal hazard, expressed in terms of probabilities of
occurrence in the next 50 years, recalling that this
period of time corresponds to the expected lifetime
of a large telescope.
some of the best astrophysical observatories in
the world, namely the canarian, chilean and
hawaiian observatories, are located within active
geological regions. This is not a coincidence, since
the sky transparency that defines good astro-
nomical sites is the result of the combination of
factors, directly or indirectly related to geological
activity, such as altitude, local topography and/or
atmospheric stabilization induced by the presence
of water bodies (
e.g.
ocean). increasingly larger
telescopes (10 and 40 metres classes) demand sta-
ble structures and buildings, and hence geological
activity becomes an important parameter to take
into account in astronomical site ranking. The
structures of large telescopes have and will have
to withstand the effects associated to seismic and/
or volcanic activity, but they also have to minimize
the loss of operational time, recalling the extreme
precision in the alignment of mechanical and opti-
cal components (salmon 2007).
