A combination of high - technical school lasers and ground - penetrating microwave radar have led to the rediscovery of 150 - class - former military infrastructure bury below California ’s notorious Alcatraz prison .
Before it was the world ’s most notorious ( and “ inescapable ” ) penitentiary , the island of Alcatraz served as a military base from1850 until 1933 . build into an island smack dab in the middle of some of San Francisco Bay ’s most intimidating stream , the island is both within eyesight from the downtown con and bustle of the urban center while at the same time is isolate due to its shark - infest frigid water .
When the prison was ramp up at the turn of the 20th century , the former military base would not have been protected under ethnic heritage and protection natural law at the clip , leading builders to “ essentially bulldoze ” the former military installation . investigator wanted to see what – if any – of the fortification were impart following the transition .
“ In converting the domain to a prison , the Brobdingnagian absolute majority of the previous military history of the island had been efface , but we wondered if perhaps something of that pregnant time in both the islands and American history rest , but sink and preserve beneath the subsurface , ” explained archeologist Timothy de Smet in astatement . “ As such , we seek non - trespassing , non - destructive mean to insure if any historic archaeological remains dwell beneath several section of the island , like the Recreation Yard of the infamous US Federal penitentiary . We did not bonk what to expect . We did not know if there would be any extant subsurface architecture of these historically meaning remains , or if there was anything left , what their extent and wholeness would be like . ”
Using sublunar optical maser scan , terra firma - penetrating radiolocation datum , and georectification ( the mental process of taking old digitized maps and linking them to a coordinate scheme so that they can be accurately geolocated in 3D space ) , the team was able to find and analyze diachronic stay beneath what used to be the recreation yard for the prison . Writing in the journalNear Surface Geophysics , the team reports that remnants of former bury structure , “ bomb shelter ” earthwork traverses , vaulted brick masonry burrow , and ventilation channel continue in shockingly estimable condition .
“ The remains of these historic archeology features were just a few centimeter beneath the surface and they were miraculously and impeccably preserve . The concrete facing of the Recreation Yard trading floor is fantastically thin and , in fact , in places sitting directly atop the architecture from the 1860s , ” enjoin de Smet . " We also teach that some of the earthwork traverses were cut through over with thin concrete layers through time , potential to lessen eroding on the showery windy island . It was wonderful to find the history just beneath our groundwork that we can visualize for the public . ”
The researchers say this drill can be applied to other diachronic structures around the country , exhibit how modern technology can answer questions about human deportment without threatening the unity of historical sites .
Today , Alcatraz is designated a National Historic Landmark and is opened to the public for tours .
