7 ms·

Machu Picchu was built over major fault zones (2019)

102 points by Anon84 5y ago

adolph 5y ago
Title needs 2019. The only source link in the article goes to a 2019 presentation abstract: https://gsa.confex.com/gsa/2019AM/webprogram/Paper330598.html https://gsa.confex.com/gsa/2019AM/webprogram/Paper330598.htm...
- deleted 5y ago
  [deleted]
daniel-cussen 5y ago
The construction of the buildings, you know, jigsaw pieces of rock, made perfect sense when I flashed on it the other day. I've lived in the Andes. The worst earthquakes. A building made of tesselated bricks would not survive, whereas a building made of jigsaw rocks held together by gravity will allow the earthquake to lift its rocks, but they will fall into place in the exact same way they were when the earthquake's over.
- kibwen 5y ago
  Words don't quite do their stonework justice. Plenty of old-world architecture is made of whatever weirdly-shaped rocks they had lying around, but they use mortar to hold them together. The Incan mortar-less stone puzzle look is extremely cool: https://commons.wikimedia.org/wiki/File:Mur_Inca_D%C3%A9cembre_2007.jpg https://commons.wikimedia.org/wiki/File:Mur_Inca_D%C3%A9cemb... "Usually the walls of Incan buildings were slightly inclined inside and the corners were rounded. This, in combination with masonry thoroughness, led Incan buildings to have a peerless seismic resistance thanks to high static and dynamic steadiness, absence of resonant frequencies and stress concentration points. During an earthquake with a small or moderate magnitude, masonry was stable, and during a strong earthquake stone blocks were “ dancing ” near their normal positions and lay down exactly in right order after an earthquake."
  - knolax 5y ago
    Don't stone walls in Europe use the same technique?
    - robinsoh 5y ago
      Not to my knowledge. Almost all European stone walls all use mortar. Drystan is more like piling rocks together. They aren't shaped. The Inca (or possibly their predecessor civilization) techniques at Sacsayhuaman and Machu Picchu are far more advanced. It is still unclear exactly how they achieved those structures. We're talking about 140 tonne rocks being put together to form those structures and assembled without mortar in such a way that one can't slip a piece of paper in between rocks. When the Conquistadors encountered the structures, they had no idea how they were being made or put together. They pulled them apart and used the pulled apart chunks with mortar to build cathedrals that mostly fell apart every time there was a tectonic movement. It breaks my heart that we don't know how to build such structures to this day. We use cement concrete which is a massive source of CO2 production. If we could have somehow preserved the knowledge of how those structures were built instead of burning their books-khippus, and killing their stone masons and scientists, we could have had a very different modern world today.
      - kiba 5y ago
        They have a whole field called experimental archaeology that's exactly about these sort of things.
        robinsoh 5y ago
        I'm unsure what you're trying to communicate.
    - deleted 5y ago
      [deleted]
- kumarvvr 5y ago
  Are there any modern construction equivalents to such construction? Or have we surpassed and come up with better models?
  - Zenst 5y ago
    Tuned dampning would be one of the main ways in modern times and nice read about such things :- https://blog.jumpstartinsurance.com/more-ways-to-keep-buildings-safe-in-earthquakes/ https://blog.jumpstartinsurance.com/more-ways-to-keep-buildi...
  - dumbfoundded 5y ago
    Wood works pretty well. If you live in California, you don't see a lot of houses built out of brick.
    - Zenst 5y ago
      True, though costs may also be a factor. Was interested in what the oldest buildings in California would be and https://en.wikipedia.org/wiki/List_of_the_oldest_buildings_in_California https://en.wikipedia.org/wiki/List_of_the_oldest_buildings_i... Darn, you have to love arches in buildings - do seem to stand the test of times well. Also wondering if that is a lime render being used and if that is useful in dispersing resonance in the structure - I'm thinking yes.
      - dumbfoundded 5y ago
        A lime render may help: https://www.zdnet.com/article/seismic-fabric-could-protect-old-buildings-from-earthquake-harm/ https://www.zdnet.com/article/seismic-fabric-could-protect-o...
      - goto11 5y ago
        I was really confused the oldest building in California was a monastery from 1181. Apparently it was built in Spain in the middle ages, but in 1931 was purchased by an American billionaire and shipped to California!
- Zenst 5y ago
  Resonance would be a key factor as well, various sized rocks all at irregular angles would help greatly to prevent any overall resonance shaking and amplifying across the structure. Now in contrast to standard sized bricks and regimental formations - like a row of pitchforks just awaiting the right note in many ways. Then buildings of old had less engineering and material science to lean onto. That combined with a shift of building things to last forever towards a lifetime and even that lifetime gets shorter. We see things built with just enough materials to do the job and know more with a life of 100 years at best in so many cases (often half that with some housing). Sadly it gets down to the numbers and odds as well - if there is say 1 in 100 years chance of a quake that would be over 6 on the scale and 1 in 500 of a 7 and the cost to build is 1m for upto level 5 survivability and 5 million for level 6 and 50m for level 7. You see how the insurance can push it towards going for the cheaper option on the bases that if you went for a level 5 - you could rebuild it 5 times in that 100 years. So money does play a huge part as always. I do wonder, what would it cost today to build Machu Picchu as it is - a huge amount and can bet the modern approach would involve concrete and reinforced steel. Just can't beat natural stone still in many ways.
  - mark336 5y ago
    I am Peruvian. I wonder if the Incas built there buildings with irregular rocks only to prevent resonance or because it was too difficult to carve rocks of the same size...
    - WalterBright 5y ago
      > or because it was too difficult to carve rocks of the same size The by far most likely explanation. Especially if your only tools were other rocks.
      - robinsoh 5y ago
        > Especially if your only tools were other rocks. This is not a entirely valid assumption. It has not been proven that these civilizations only had stone tools. Attempting to portray them as primitive people with only stone tools is highly reductive given the level of sophistication of the structures they managed to create. They may have had sophisticated chemical processes to shape and form rock structures. A simple proof is just by looking at these structures and seeing that even today in 2021, we are unable to form equivalent structures ourselves using modern cranes and rock shaping tools. It is terrible that the knowledge was destroyed by burning their books-khippus and extinguishing their stone masons, technicians and scientists.
keyle 5y ago
I wonder what other cases have let humanity to do the absolutely wrong choice, because it was the easiest to way forward... It makes me think about evolution.
- ngokevin 5y ago
  Mexico City built a hard way, searching for an eagle eating a snake on top of a rock. They found it on a lake bed. As a result, they built on some pretty soft sinking layers. Favorite city though, lived there last month and going to Machu Picchu again this weekend.
- dylan604 5y ago
  I think you're stealing credit as we've made deliberate decisions that were bad and not easy too. For example, we built New Orleans.
  - Forge36 5y ago
    It didn't start bad. It used to be the highest point, and it didn't flood! Unfortunately the city grew. Eventually flood mitigations were added, this made the sinking worse.
    - klysm 5y ago
      Which almost makes it an example for the exact opposite.
    - WalterBright 5y ago
      The British figured out how to build in a swamp long before: https://www.youtube.com/watch?v=w82CqjaDKmA https://www.youtube.com/watch?v=w82CqjaDKmA
  - keyle 5y ago
    Heh. I'm not from the US and have no idea about what you're referring to regarding New Orleans. First off, where was Old Orlean? And I take it... a sinking problem similar to Venezia?
ufo 5y ago
For those that understand Portuguese, the author of that paper appeared in the Fronteiras da Ciência podcast to talk about the work. Season 11, Episode 12, (2020-05-25) http://www.ufrgs.br/frontdaciencia/ http://www.ufrgs.br/frontdaciencia/ Fronteiras da Ciência is a podcast that I can't recommend highly enough. In-depth science interviews that don't dumb it down or stray off topic.
apsdsm 5y ago
Unrelated, but is it just not possible any more for anybody to write a title for an article that doesn't sound like it was composed by a click-bait robot?
- vmception 5y ago
  No, because they don't get read, they don't reach the front page, they don't get the engagement boost from people complaining about it and you would never see it.
- xboxnolifes 5y ago
  Titles have always been written for engagement, we've merely optimized it further over time.
- rconti 5y ago
  Here I was reading this mercifully brief article, just glad it didn't start with "It was a stormy night in 2014 when I began researching..."
- gremloni 5y ago
  This title agrees with the content though.
- keyle 5y ago
  Totally agree, I hate reading these titles. To the credit of the writer though, we get the answer fairly soon and the article isn't 24 paragraphs deep.
- deleted 5y ago
  [deleted]
  - deleted 5y ago
    [deleted]
- UncleOxidant 5y ago
  I half expected it to be something about The Fifth Season.
vmception 5y ago
> that's where building materials for the site—large amounts of already fractured rock—were readily available [two paragraphs of somewhat supporting evidence] you're welcome
1cvmask 5y ago
Are there any other such examples of building over major fault zones historically because of the ready availability of fractured rocks?
- redis_mlc 5y ago
  Maybe we can dump several thousand tons of nuclear waste into a fault: "In June 2012 S. David Freeman, the former head of the Southern California Public Power Authority and "a longtime anti-nuclear voice",[30] described San Onofre and Diablo Canyon as "disasters waiting to happen: aging, unreliable reactors sitting near earthquake fault zones on the fragile Pacific Coast, with millions of Californians living nearby". The San Onofre plant used seawater for cooling, like some other seaside facilities in Southern California, lacking the large cooling towers typically associated with nuclear generating stations. Limited available land next to SONGS would likely have required towers to be built on the opposite side of Interstate 5.[32] More than 4,000 tons of radioactive waste are stored at San Onofre." https://en.wikipedia.org/wiki/San_Onofre_Nuclear_Generating_Station https://en.wikipedia.org/wiki/San_Onofre_Nuclear_Generating_...
- furins 5y ago
  Probably in many places along the Alpine Himalayan mountain range, including Algerie, Italy, Greece, Turkey, Iran, Afghanistan, India, among others. These mountainous areas are usually heavily fractured by faults and the resulting rock blocks have been used for millennia to build walls. It's rather hard to say if rock availability is the only reason that drove people to build in a given place: usually major faults zones are eroded by rivers and form valleys. this places are preferable building sites because of water availability, easiness of transportation along the river, etc. (sorry for my English)
- lostlogin 5y ago
  In case you missed it, the article says the below: Further evidence that the site selection for Machu Picchu may not have been an accident: Similar analyses reveal other ancient Incan sites, including Ollantaytambo, Pisac, and Cusco were also built at the intersections of fault zones.
adolph 5y ago
Sourced from a presentation abstract: HOW INCAS USED GEOLOGICAL FAULTS TO BUILD THEIR SETTLEMENTS

102 points by Anon84 5y ago

Title needs 2019. The only source link in the article goes to a 2019 presentation abstract: https://gsa.confex.com/gsa/2019AM/webprogram/Paper330598.html https://gsa.confex.com/gsa/2019AM/webprogram/Paper330598.htm...

deleted 5y ago
[deleted]

daniel-cussen 5y ago

The construction of the buildings, you know, jigsaw pieces of rock, made perfect sense when I flashed on it the other day. I've lived in the Andes. The worst earthquakes. A building made of tesselated bricks would not survive, whereas a building made of jigsaw rocks held together by gravity will allow the earthquake to lift its rocks, but they will fall into place in the exact same way they were when the earthquake's over.

kibwen 5y ago
Words don't quite do their stonework justice. Plenty of old-world architecture is made of whatever weirdly-shaped rocks they had lying around, but they use mortar to hold them together. The Incan mortar-less stone puzzle look is extremely cool: https://commons.wikimedia.org/wiki/File:Mur_Inca_D%C3%A9cembre_2007.jpg https://commons.wikimedia.org/wiki/File:Mur_Inca_D%C3%A9cemb... "Usually the walls of Incan buildings were slightly inclined inside and the corners were rounded. This, in combination with masonry thoroughness, led Incan buildings to have a peerless seismic resistance thanks to high static and dynamic steadiness, absence of resonant frequencies and stress concentration points. During an earthquake with a small or moderate magnitude, masonry was stable, and during a strong earthquake stone blocks were “ dancing ” near their normal positions and lay down exactly in right order after an earthquake."
- knolax 5y ago
  Don't stone walls in Europe use the same technique?
  - robinsoh 5y ago
    Not to my knowledge. Almost all European stone walls all use mortar. Drystan is more like piling rocks together. They aren't shaped. The Inca (or possibly their predecessor civilization) techniques at Sacsayhuaman and Machu Picchu are far more advanced. It is still unclear exactly how they achieved those structures. We're talking about 140 tonne rocks being put together to form those structures and assembled without mortar in such a way that one can't slip a piece of paper in between rocks. When the Conquistadors encountered the structures, they had no idea how they were being made or put together. They pulled them apart and used the pulled apart chunks with mortar to build cathedrals that mostly fell apart every time there was a tectonic movement. It breaks my heart that we don't know how to build such structures to this day. We use cement concrete which is a massive source of CO2 production. If we could have somehow preserved the knowledge of how those structures were built instead of burning their books-khippus, and killing their stone masons and scientists, we could have had a very different modern world today.
    - kiba 5y ago
      They have a whole field called experimental archaeology that's exactly about these sort of things.
      - robinsoh 5y ago
        I'm unsure what you're trying to communicate.
  - deleted 5y ago
    [deleted]
kumarvvr 5y ago
Are there any modern construction equivalents to such construction? Or have we surpassed and come up with better models?
- Zenst 5y ago
  Tuned dampning would be one of the main ways in modern times and nice read about such things :- https://blog.jumpstartinsurance.com/more-ways-to-keep-buildings-safe-in-earthquakes/ https://blog.jumpstartinsurance.com/more-ways-to-keep-buildi...
- dumbfoundded 5y ago
  Wood works pretty well. If you live in California, you don't see a lot of houses built out of brick.
  - Zenst 5y ago
    True, though costs may also be a factor. Was interested in what the oldest buildings in California would be and https://en.wikipedia.org/wiki/List_of_the_oldest_buildings_in_California https://en.wikipedia.org/wiki/List_of_the_oldest_buildings_i... Darn, you have to love arches in buildings - do seem to stand the test of times well. Also wondering if that is a lime render being used and if that is useful in dispersing resonance in the structure - I'm thinking yes.
    - dumbfoundded 5y ago
      A lime render may help: https://www.zdnet.com/article/seismic-fabric-could-protect-old-buildings-from-earthquake-harm/ https://www.zdnet.com/article/seismic-fabric-could-protect-o...
    - goto11 5y ago
      I was really confused the oldest building in California was a monastery from 1181. Apparently it was built in Spain in the middle ages, but in 1931 was purchased by an American billionaire and shipped to California!
Zenst 5y ago
Resonance would be a key factor as well, various sized rocks all at irregular angles would help greatly to prevent any overall resonance shaking and amplifying across the structure. Now in contrast to standard sized bricks and regimental formations - like a row of pitchforks just awaiting the right note in many ways. Then buildings of old had less engineering and material science to lean onto. That combined with a shift of building things to last forever towards a lifetime and even that lifetime gets shorter. We see things built with just enough materials to do the job and know more with a life of 100 years at best in so many cases (often half that with some housing). Sadly it gets down to the numbers and odds as well - if there is say 1 in 100 years chance of a quake that would be over 6 on the scale and 1 in 500 of a 7 and the cost to build is 1m for upto level 5 survivability and 5 million for level 6 and 50m for level 7. You see how the insurance can push it towards going for the cheaper option on the bases that if you went for a level 5 - you could rebuild it 5 times in that 100 years. So money does play a huge part as always. I do wonder, what would it cost today to build Machu Picchu as it is - a huge amount and can bet the modern approach would involve concrete and reinforced steel. Just can't beat natural stone still in many ways.
- mark336 5y ago
  I am Peruvian. I wonder if the Incas built there buildings with irregular rocks only to prevent resonance or because it was too difficult to carve rocks of the same size...
  - WalterBright 5y ago
    > or because it was too difficult to carve rocks of the same size The by far most likely explanation. Especially if your only tools were other rocks.
    - robinsoh 5y ago
      > Especially if your only tools were other rocks. This is not a entirely valid assumption. It has not been proven that these civilizations only had stone tools. Attempting to portray them as primitive people with only stone tools is highly reductive given the level of sophistication of the structures they managed to create. They may have had sophisticated chemical processes to shape and form rock structures. A simple proof is just by looking at these structures and seeing that even today in 2021, we are unable to form equivalent structures ourselves using modern cranes and rock shaping tools. It is terrible that the knowledge was destroyed by burning their books-khippus and extinguishing their stone masons, technicians and scientists.

keyle 5y ago

I wonder what other cases have let humanity to do the absolutely wrong choice, because it was the easiest to way forward... It makes me think about evolution.

ngokevin 5y ago
Mexico City built a hard way, searching for an eagle eating a snake on top of a rock. They found it on a lake bed. As a result, they built on some pretty soft sinking layers. Favorite city though, lived there last month and going to Machu Picchu again this weekend.
dylan604 5y ago
I think you're stealing credit as we've made deliberate decisions that were bad and not easy too. For example, we built New Orleans.
- Forge36 5y ago
  It didn't start bad. It used to be the highest point, and it didn't flood! Unfortunately the city grew. Eventually flood mitigations were added, this made the sinking worse.
  - klysm 5y ago
    Which almost makes it an example for the exact opposite.
  - WalterBright 5y ago
    The British figured out how to build in a swamp long before: https://www.youtube.com/watch?v=w82CqjaDKmA https://www.youtube.com/watch?v=w82CqjaDKmA
- keyle 5y ago
  Heh. I'm not from the US and have no idea about what you're referring to regarding New Orleans. First off, where was Old Orlean? And I take it... a sinking problem similar to Venezia?

ufo 5y ago

For those that understand Portuguese, the author of that paper appeared in the Fronteiras da Ciência podcast to talk about the work. Season 11, Episode 12, (2020-05-25) http://www.ufrgs.br/frontdaciencia/ http://www.ufrgs.br/frontdaciencia/ Fronteiras da Ciência is a podcast that I can't recommend highly enough. In-depth science interviews that don't dumb it down or stray off topic.

apsdsm 5y ago

Unrelated, but is it just not possible any more for anybody to write a title for an article that doesn't sound like it was composed by a click-bait robot?

vmception 5y ago
No, because they don't get read, they don't reach the front page, they don't get the engagement boost from people complaining about it and you would never see it.
xboxnolifes 5y ago
Titles have always been written for engagement, we've merely optimized it further over time.
rconti 5y ago
Here I was reading this mercifully brief article, just glad it didn't start with "It was a stormy night in 2014 when I began researching..."
gremloni 5y ago
This title agrees with the content though.
keyle 5y ago
Totally agree, I hate reading these titles. To the credit of the writer though, we get the answer fairly soon and the article isn't 24 paragraphs deep.
deleted 5y ago
[deleted]
- deleted 5y ago
  [deleted]
UncleOxidant 5y ago
I half expected it to be something about The Fifth Season.

vmception 5y ago

> that's where building materials for the site—large amounts of already fractured rock—were readily available [two paragraphs of somewhat supporting evidence] you're welcome

1cvmask 5y ago

Are there any other such examples of building over major fault zones historically because of the ready availability of fractured rocks?

redis_mlc 5y ago
Maybe we can dump several thousand tons of nuclear waste into a fault: "In June 2012 S. David Freeman, the former head of the Southern California Public Power Authority and "a longtime anti-nuclear voice",[30] described San Onofre and Diablo Canyon as "disasters waiting to happen: aging, unreliable reactors sitting near earthquake fault zones on the fragile Pacific Coast, with millions of Californians living nearby". The San Onofre plant used seawater for cooling, like some other seaside facilities in Southern California, lacking the large cooling towers typically associated with nuclear generating stations. Limited available land next to SONGS would likely have required towers to be built on the opposite side of Interstate 5.[32] More than 4,000 tons of radioactive waste are stored at San Onofre." https://en.wikipedia.org/wiki/San_Onofre_Nuclear_Generating_Station https://en.wikipedia.org/wiki/San_Onofre_Nuclear_Generating_...
furins 5y ago
Probably in many places along the Alpine Himalayan mountain range, including Algerie, Italy, Greece, Turkey, Iran, Afghanistan, India, among others. These mountainous areas are usually heavily fractured by faults and the resulting rock blocks have been used for millennia to build walls. It's rather hard to say if rock availability is the only reason that drove people to build in a given place: usually major faults zones are eroded by rivers and form valleys. this places are preferable building sites because of water availability, easiness of transportation along the river, etc. (sorry for my English)
lostlogin 5y ago
In case you missed it, the article says the below: Further evidence that the site selection for Machu Picchu may not have been an accident: Similar analyses reveal other ancient Incan sites, including Ollantaytambo, Pisac, and Cusco were also built at the intersections of fault zones.

adolph 5y ago

Sourced from a presentation abstract: HOW INCAS USED GEOLOGICAL FAULTS TO BUILD THEIR SETTLEMENTS