Chile’s major northern astronomical observatories escaped damage from the Magnitude 8.2 earthquake that struck off its northern coast at 8:46 pm (local time) Tuesday night, the European Southern Observatory (ESO) reports.
“null last night,” ESO astronomer emeritus Massimo Tarenghi told Forbes.com by phone from ESO’s Santiago offices. However, ESO said in a separate statement that although it had no casualties among its staff, it offered its “deepest condolences” to the families of the victims.
ESO operates three separate observatories in northern Chile. They range from its VLT complex at Paranal Observatory; to the international ALMA collaboration in the northern Atacama Desert’s Chajnantor Plateau; to its La Silla Observatory about an hour’s flight north of Santiago.
“Astronomers at the VLT felt it, but they didn’t even stop observations,” said Tarenghi, the telescope’s former project manager. “The telescopes already compensate for wind vibration, so vibration from an earthquake is compensated for by the telescope’s [automatic system] of guiding and tracking.”
The earthquake’s epicenter was located some 500 km (310 mi) from the VLT (Very Large Telescope) and almost a 1000 km (620 mi) from the La Silla observatory.
“At La Silla, we have earthquakes of a certain frequency but they’re typically small,” said Tarenghi. “In the [far] north they are less in number but when they come they are very, very strong.”
The USGS reports the earthquake was the result of that it termed “thrust faulting at shallow depths near the Chilean coast” which it says are consistent with “megathrust” between the two large Nazca and South American tectonic plates.
“Paranal itself sits on a fault which can be seen very well from satellite images,” said Tarenghi. “So, we had to [make design provisions] for all earthquakes up to 9 to 9.5 magnitude.”
The VLT’s famous “Residencia” — featured in the James Bond film “Quantum of Solace” — is constructed in reinforced concrete. Its 200-meter long structure is split in two segments so it can move during seismic activity without breaking.
But Tarenghi says the real earthquake risk at Paranal — which lies on a mountaintop plateau only a few mi from the coast — is with potential damage to the VLT’s large 8.2-meter mirrors.
Under extreme vibration, Tarenghi says additional supports are designed to automatically deploy from underneath each 8.2-meter mirror. He says in such instances, the large mirrors would also be protected from the topside by airbags designed to shield their precious highly-polished surfaces.
Although Tarenghi says ESO is saddened by the loss of life and injury in this most recent earthquake, he notes that the observatory remains undeterred by northern Chile’s inherent earthquake threat.
To that end, ESO plans on completing its $1.4 billion dollar E-ELT (European Extremely Large Telescope) by early next decade.