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Thursday, December 19, 2013

Popocatépetl Resurgent: How do you know when you’re done with your search?

As we saw in the discussion about Popocatépetl and the lahars, the basic question is pretty simple to say: “Did an outflow from the volcano ever reach the base of the pyramid in Cholula?”

We found some credible sources that told us that the lahars reached the base of the Great Pyramid. But then Ramón discovered the work of Patricia Plunket.

Let’s summarize the evidence:

Pro --

The idea of the lahars reaching the base of the pyramid seems to originate with the paper:

“Repeated volcanic disasters in Prehispanic time at Popocatépetl, central Mexico: Past key to the future?” Claus Siebe, et al., Geology, v. 24, p. 399-402 (May, 1996).

In this paper, the authors argue that a large eruption flooded the area around the Great Pyramid on Cholula with lahar outflows. (Remember that lahars are rivers of superhot mud, rocks, and generally nasty stuff that can travel up to 50 miles from the original volcano at speeds of up to 90 mph.

If you look at Figure 1 from their paper, it's clear they think the Pyramid was hit by the lahars:

As the authors write:

"Our investigations indicate that a major cataclysmic eruption occurred at Popocatépetl at about this time, affecting a minimum area of 3000 km^2. In addition to the volcanic hazards associated with the base surges, pumice falls, and ash flows, widespread volcanic mudflows reached the base of the great pyramid of Cholula (Figs. 1 and 3). The sequence of volcanic mudflow deposits is several metres thick and contains abundant pumice, pottery shards, obsidian artifacts, and carbon. Carbon from this sequence at Cholula yielded an age of A.D. 790 (+/- 175)."

The claim is repeated in a more recent book: Neogene-Quaternary Continental Margin Volcanism: A Perspective from México, Issue 402, Geological Society of America, edited by Claus Siebe, José Luis Macías, Gerardo J. Aguirre-Díaz (Geological Society of America, Jan 1, 2006)

Claus Siebe, also wrote a few more papers with this same claim.

Sheridan, M.F., Hubbard, B., Bursik, M.I., Siebe, C, Abrams, M., Macias, J.L., and Delgado, H (2001) “Short-term potential volcanic hazards at volcan Popocatepetl, Mexico” EOS, American Geophysical Union, 82:185-189.

Siebe, C., & Macías, J. L. (2006). “Volcanic hazards in the Mexico City metropolitan area from eruptions at Popocatépetl, Nevado de Toluca, and Jocotitlán stratovolcanoes and monogenetic scoria cones in the Sierra Chichinautzin Volcanic Field” SPECIAL PAPERS-GEOLOGICAL SOCIETY OF AMERICA, 402, 253.

But it’s interesting to note that the text used to describe the 822 AD lahars reaching the foot of the Great Pyramid in Cholula is exactly the same each time (suggesting that the text was simply copied from paper to paper without any newer data).

Then there is additional work that agrees with this that we’ve already found.

http://volcano.oregonstate.edu/vwdocs/volc_images/north_america/mexico/popos_potential.html Written by Michael Abrams, Volcanologist, NASA/Jet Propulsion Laboratory, Pasadena, CA. But writing on the Oregon State “Volcano World” web site, Department of Geosciences at Oregon State University. Abrams is a co-author on a paper about Popo that was written by M. Sheridan (who is at SUNY Buffalo, NY).

The downside of this web document is that it’s just a note, not an official publication. There are no references, etc. But it seems reasonably believable. As we see, the author comes from a credible institution and has good credentials in this area.

ON THE OTHER HAND…

Fred wrote in with an intriguing comment in the stream:

Google Search [ Popocatepetl caldera formed ] and find a book "Geology of México: Celebrating the Centenary of the Geological Society of México" pp 199-201 Page 201 has a great timeline/stratigraphic image of past eruptions.

I go back and try to find another source for flow reaching the pyramid [ pyramid cholula 850..700 lahar ] but the range search but the range search doesn't appear to work in reverse, so [ pyramid cholula 700..850 lahar ] to and discover the Mesoamerican Research Foundation.

The Google Quick Scroll extension leads me to this passage: "NOTE: Beginning in 1993, scientific studies find that volcanic activity has produced several eruptions, two of which were the most violent. The first was, ''at the beginning of the present era'' or first century A.D. The second was, ''between A.D. 700 and 850.'' (Plunket & Urunuela 1998)."

I repeated Fred’s search for [ Plunket & Urunuela 1998 ] and found the PDF for the paper.

Plunket, P., and G. Uruñuela. "Mountain of sustenance, mountain of destruction: The prehispanic experience with Popocatépetl volcano." Journal of Volcanology and Geothermal Research 170.1 (2008): 111-120.

This paper talks about the artifacts and radiocarbon dating of artifacts found at the site suggesting they were covered sometime between 700-900AD.

But one of the key points made in this paper is that:

“...a zone that should show the presence of these deposits if indeed they reached the Pyramid – to date have failed to find stratigraphic evidence of these lahars (López et al., 2002a,b; Plunket and Uruñuela, 2002b, 2005a,b).”

Later in that paper, the authors write:

“Excavations on the campus of the Universidad de las Américas to the east of the Great Pyramid have demonstrated that, in areas where stratigraphy is intact, lahar deposits are also absent although a sterile layer of sandy volcanic ash consistently seals the black clay deposits of the Classic period; cultural materials overlying this layer belong to the Early Postclassic (Plunket and Uruñuela, 2005b, p.103)."

SO… What have we found here?

We’ve found that the story isn’t quite as cut and dried as I thought.

The Siebe crowd believes that the evidence is quite clear that the lahar flow of ca. 800 AD reached the based of the Great Pyramid. The Plunket crowd disagrees.

We are in the middle of an old-fashioned scientific disagreement, with evidence being mounted on both sides.

I’ve spent about 8 hours quite happily reading through the literature of volcanoes and archaeology in the area of Puebla and Colula. It’s been hugely fun, but in the end, both groups are arguing about whether or not the lahars made it all the way to the Pyramid or not.

A big problem for the Plunket argument is the some of the basic work is not generally available. Here’s a citation that’s given:

Panfil, Maria S. “The Late Holocene volcanic stratigraphy of the Tetimpa area, northeast flank of Popocatépetl volcano, central Mexico.” Unpublished MS thesis in Geosciences, Pennsylvania State University, College Park (1996)

Well.. THAT’s hard to check out!

On the other hand, most of that paper seems to be covered in a later publication (which is pretty typical of scientific papers) in:

Panfil, Maria S., Thomas W. Gardner, and Kenneth G. Hirth “Late Holocene Stratigraphy of the Tetimpa Archaeological Sites, Northeast Flank of Popocatépetl Volcano, Central Mexico” Geological Society of America Bulletin 111(2): 204-218 (1999).

And so it goes, back and forth. Plunket (an archaeologist) disagrees with Siebe’s (the geologist) interpretation of what’s seen at the pyramid site. Is it a mud flow from the volcano? Or just the melting of adobe bricks over the years down onto the plain?

I don’t think we’re going to be able to figure this out by just web searches. This is really a case where we now understand that there is evidence for, and evidence against. We could read through all of the literature and make a reasoned guess at the evidence, but that’s the job of a geology (or archaeology) graduate student.

Note that this kind of conversation happens ALL the time in the Talk pages of Wikipedia. You can see this even in something as innocuous as the Wikipedia page on Chocolate. If you read the “Talk” page for Chocolate, you’ll see an animated debate about what should go into the article on chocolate, even reaching into politically charged topics such as child slavery!

And, of course, this kind of open debate about evidence and conclusions is just the normal operation of science. Even in fields where the “standard interpretation” would seem to be fairly stable, new interpretations arise, sometimes by people from outside of the field. See, for instance, Nathan Myhrvold’s critique of growth rate data in dinosaurs in which he questions the well-accepted data and analysis of how quickly dinosaurs grew. (NY Times article) and his own publication site, which reprints an article he authored in PLOS One (a fairly respected online with peer reviewed articles, but are not excluded on the basis of lack of perceived importance or adherence to a scientific field).

And of course we should note that some “discoveries” aren’t QUITE that… See the article about the re-discovery of the anterolateral-ligament (ALL) for a discussion about how the ALL was “re-discovered” (but really wasn’t).

FWIW, I first saw this in the NYTimes Magazine (“A team of Belgian doctors recently confirmed the existence of a new ligament in the human knee…”) 12/8/13, and when I checked on it, the story had pretty clearly been blown up out of proportion.

Search lesson: Overall, then, the key search lesson from our Popo adventure is that it’s well worth looking around a bit more after finding your initial result. Discoveries are often not what you think when they're first noted. Subsequent articles frequently update recieved knowledge. Hint: Look for variations in the answers; and sometimes, just sometimes, you stumble into a very fun debate. And we realize once more that not all of science and history is quite as locked-down we'd thought. Sometimes you really have to go beyond just a simple lookups of facts.

MANY THANKS to the SearchResearchers who pointed out the alternative interpretations of the "lahar" flows around the Great Pyramid in Cholula. Special shout-out to Ramón and Fred, who went the extra mile to contact the authors of some of these reports and dig more deeply into the topic.

Continuation: What's that word again?

Looks like we've fallen into a really hard search challenge. Excellent! It's been a while since we've all been quite as stumped as we are with this one.

From the comments, it looks like people are on the right track... you just haven't found quite the right words to rephrase the question.

Remember:

Today's challenge:

1. What's the Japanese term for a publisher taking a writer out of their life and secreting them away in a hotel until they've completed writing the book that they're obligated to write?

As you know, once you have the specific term for a complex idea, it's much easier to do subsequent searches

I'll give the answer tomorrow, but we'll continue this for just a bit more to let folks have a bit more time to work on it!

Search on!

Wednesday, December 18, 2013

Wednesday search challenge (12/18/13): What's that word again? The challenge of cross-cultural search

One of the biggest search challenges I face is finding something that captures an idea in another culture that's uniquely within that culture.

While many of the ideas, concepts, and words we use to talk about the world are shared between cultures (the color red, for example, is pretty much a universal), some are not, but are embedded with a particular cultural context. And in particular, those ideas are usually captured in a bit of language.

For example, in languages that have a formal and an informal voice (such as tu vs. Usted in Spanish; du vs. Sie in German, etc.), there is usually a word to express the concept "I'd like to address you using the informal voice." This doesn't really exist in English. The closest English comes to this concept is the phrase "we're on a first-name basis." By contrast, Spanish has a perfectly good verb for this: tutear, which means to shift from formal to informal (that is, from Usted to tu).

As a consequence, it's sometimes difficult to search for concepts and ideas that aren't native to your own culture and language. Why? Because you don't know where to start. Luckily, I learned tutear years ago, so I don't have to search for it.

But that leads me to today's Search Challenge. Here's my true story of another cultural search puzzle...

I spoke with a Japanese friend several years ago about what it's like to be a writer in Japan. She told me about this really interesting cultural practice that takes place (apparently) exclusively in Japan.

If an author is under contract to write a book for a publishing house, and the writer hasn't really produced the book by the due date of the contract, the publishing house can spirit that person away and keep them in a hotel room (effectively under house arrest) until they finish writing the book.

That cultural practice struck me. Can this really be true?

I've checked. Yes, it's really true. But I had a bit of a tricky time figuring out what this practice is called. Can you figure out what it is?

Today's challenge:

1. What's the Japanese term for a publisher taking a writer out of their life and secreting them away in a hotel until they've completed writing the book that they're obligated to write?

As you know, once you have the specific term for a complex idea, it's much easier to do subsequent searches. Question is.. how do you get started?

Once you've found the answer, be sure to let us know HOW you found it! (What search terms did you try... especially the paths that didn't work.) What we're trying to learn in this challenge is the skill of cross-cultural search.

So, as you search, keep track of what you've attempted and how long (roughly) you spent. Today's challenge isn't a race, but being aware of how long you're spending on a particular search strategy is a useful skill to have.

Let us know how you do. (And if you happen to know it because you lived in Japan, that's great too. Just let us know!)

Search on!

Friday, December 13, 2013

Update... Friday's post?

Hi folks... I know I promised to write something about "How we know when to stop searching?" ... which is kind of a variant of "How do we know when something is right / correct / accurate / credible?"

And I've been searching and researching on the topic of Popo and the lahar mudflows. (Did they, or did they NOT make it to the foot of the Grand Pyramid in Cholula?)

So far, I've spent around 4 hours on this really interesting topic. (I've always had a secret fascination with Mesoamerica and never really had an excuse to read all of the things I wanted to. Now I do.)

But it means that I'm not ready with my blog post for today.

I WILL say, though, that it's been fascinating reading. It looks like we accidentally stepped into the middle of a quiet archaeological ruckus. There are issues of how you know what you know, what methods are appropriate, and how things are seen. Fascinating.

I'll write more over the weekend, but I wanted to let y'all know that I'm not ignoring the blog.

It's just much more interesting than I'd thought it would be.

Searching on, in Mesoamerica...

Thursday, December 12, 2013

Answer: Tea, in Europe?

As often happens, this turned into somewhat more of a quest than I'd thought. Excellent work, SearchResearchers!

In writing this answer up, I've drawn heavily from Miguel's answer in yesterday's comments. (Thanks, Miguel. I hadn't planned on you writing in your own answer!) I've taken most of what he wrote and edited in a few of my own comments.

______________

Miguel:

My first search was [ europe tea plantations ] - very close to what Ramón, Debbie and Anne, and probably all others did. So I quickly landed on the Inntravel blog.

{ Dan: This is how I started too, looked around for a bit, then did [ worldwide tea plantations ] for comparison. It showed me a few more tea growing locations. }

When, later on, I submitted a comment, I didn't realize they were a commercial company nor I was thinking to present this as a challenge, yet. I might not have written that comment otherwise. Anyway, it didn't help that much, apparently. And no one from the company thanked me…

{ Dan: I was somewhat surprised to find Miguel's comment on the InnTravel site as well... but I figured it was him leaving a clue! }

I am a list maniac and I know there are tons of other people like me out there, ready to make lists out of anything. { Dan: This is deeply, deeply true. I'll write about the presence of lists next week... } So once I found the Dagomys and Tregothnan (and I already knew about Gorrana), I figured out that if there was a thorough list of tea plantations in Europe, those three names would have to be there.

So my next search was a simple [ dagomys | dagomis | krasnodar gorreana tregothnan ].

{Dan: Here, Miguel is using the | (aka "pipe" operator) instead of "OR" -- it means the same thing. FWIW, I would have done this search as [ tea dagomys OR dagomis OR krasnodar OR gorreana OR tregothnan ] which gives a somewhat broader set of results. The SERP always includes the word "tea" on the results. }

Turns out the only two pages showing up are the best I could get: a list (in Romanian) and a map (title in French). It helps that I can read Romance languages (that is, those two plus Spanish, Italian and Portuguese). I don't know any Romanian but I can derive some because of its similarity with these others on the same branch.

Anyway, I used Google Translate to help me understanding that "Ceaiurile din Intreaga Lume" means "Teas of the (Entire) World". Later on, I would use the available Website Translator plugin to get the full http://www.dagomystea.ru translated into English.

The harder question is determining which tea plantation is the northernmost. It's clear that Tregothnan is at higher latitude than Dagomys. Further north there's Eden Project but I wouldn't call that a tea plantation (check http://www.edenproject.com/visit-us/whats-here/plant-a-z/tea ). Pembrokeshire, in Wales (or, more precisely, the Preseli Hills, as remmij found out) is, according to the map guys, not ready yet. Remmij's news story is from 2009; but follow the link on the map and tada! they're selling tea that they make. Then again, what do they mean by "blended by hand"?

Here's what you can read on the "About" page: "Hand blended in Pembrokeshire using imported and locally grown ingredients." Wait a minute! I bet that those "local ingredients" are dried lemon, rose petals, Bergamot orange oil and so on. No tea, probably. From the map's marker description: "At present we’re in set-up stage with an aim for us to be 100% locally grown by 2015. Beyond this we have a target of 2019 to have our tea gardens matured and able to offer a full range of single estate teas from Pembrokeshire."

Are there any other tea plantations and factories in Europe? Answer: Yes, in Cornwall (England, UK), Switzerland, Italy, as you've found out, but also in France, Georgia and Turkey.

What about North America? Didn't double-check all the plantations featured on the map but the general answer is undoubtedly yes.

Can I have a list? Yes, someone in the Tea and Coffee Shop "Ethiopia" (in Chișinău, capital of Moldova, whose main language is Romanian) is extremely diligent or resourceful, having written this extensive list:http://www.ethiopiamd.com/World.html

Or better yet, a map of tea plantations around the world? Well, some other list maniac has created and has been updating this world map of tea plantations for the past 6 years.

{ Dan: This brings up the question about the southernmost tea plantations! What about those places in New Zealand?? }

Is the Russian tea plantation near Sochi really the northernmost one in Europe? No.

If not, which one is? At least Tregothnan is at higher latitude. And most likely that's still the northernmost tea plantation.

{ Dan: I looked at the other high latitude tea plantations. The only one that's close to Tregothnan is the one in British Columbia. But the lat/longs for each are:

Tragnothan Estate Tea, UK: 50.24048, -5.00548

Tea Farm in North Cowichan, Canada - 48.8535, -123.7084

making Tragnothan clearly the northernmost. Meanwhile, the southernmost tea is in:

Waikoto, NZ is at: -37.621, 175.06}

Under what name(s) is that Russian tea marketed? Дагомысчай (Dagomyschay) is the company (the group, to be precise),Краснодарский чай (Krasnodarskiy Chay) is the brand, as you can see on all the products. Krasnodarskiy means "from Krasnodar." Dagomys is the name of a district 12 km from Sochi center; Sochi, the town, lies in the Krasnodar Krai (region, administrative division).

What is their website's url? www.dagomystea.ru

In the meantime, Debbie and Anne have also found another tea company in the greater Sochi region: Matsesta!

{Dan: They found this by doing a query for [ tea production Krasnodar ], that's the name of the region area of Russia where Sochi is located. With that query they found the name of the company Matsesta and found that the tea is sold under the name "Macesta." }

This means the last two questions were wrongly put. They also claim that "The tea grown around Sochi is grown by about 6 different companies"!

I thought this would be easier for everybody than it showed to be but it turns out that I was kind of lucky on my search.

Now here's a bonus: I found a map of Europe showing how the word "tea" is rendered in each local language, colored by etymology. Turns out there's only "te", "chay", "herba thea" and our very Portuguese "chá", without the final Y, because it was imported directly from the Cantonese, without having been corrupted by Persian in between.

{ Dan: Remmij also found an up-and-coming tea plantation in upstate NY - coming in 2014, Lily and Mark Lin of Seneca Falls, originally from Qingtian County, Zhejiang (China) will be harvesting their own, locally grown Finger Lakes tea.

I went to graduate school in Rochester, NY, not far from this spot. It's a beautiful place--kinda snowy in the wintertime--but I never would have guessed it to be a future tea plantation. Just goes to show how the most unexpected things can turn up! }

-----

This was a fun challenge. My mental model of tea was Java and tropical places--I certainly didn't expect tea as far north as Cornwall or British Columbia!

Thanks again, Miguel! I think we learned a good deal from this including the power of searching in other languages, the utility of searching for lists, the usefulness of maps, and the value of taking multiple approaches in your searches. (And, non-trivially, the value of having many people work on a single problem. One of the outstanding properties of SearchResearch is that all of us working together on this find out things that no one of us would discover on their own. Truly, this is a fantastic demonstration of the value of diversity.)

Search on!

(And muito obrigado to Miguel!)

Remember, if other folks have challenges they think would be good for the crew, send them to me directly via email. (You should be able to figure out my email by now!)

Wednesday, December 11, 2013

Wednesday Search Challenge (12/11/13): Tea, grown in Europe?

Tea... up close, in the fields

Hot on the heels of last week's discussion about volcanoes (and the bigger point of "how do you know when what you've found is true?"), let's have another difficult-to-prove challenge!

(Sidebar: The discussion about Popo took a really interesting turn with Fred's deeper investigation into the lahar flows. I'll have more to say about that later this week. But if you missed the thread, go back a couple of days and read it. It's a fascinating discussion. As I said... more on this on Friday.)

But forward to today's challenge!

This challenge is from Regular Reader Miguel Viterbo who wrote in with this excellent set of questions:

_________________

I was looking for information about Sochi, the Russian town where the 2014 Winter Olympics will take place, when I read about a tea plantation that's very close to the town. It's often claimed to be "the northernmost in Europe."

Well, as a matter of fact, most Portuguese believe that Gorreana, the tea produced in the (Portuguese) Azores islands, is the only tea plantation in Europe.

I was there this Summer and learned that they claim to be the oldest remaining plantation in Europe, not the only one. Also, there is another tea plantation very close by. So, here are my questions for you:

Are there any other tea plantations and factories in Europe? What about North America? Can I have a list, or better yet, a map of tea plantations around the world?
Is the Russian tea plantation near Sochi really the northernmost one in Europe? If not, which one is?
By the way, under what name(s) is that Russian tea marketed? What is their website's url?

It took me a while but I managed to solve all the questions. The best results I found are a map and, on the other hand, a wonderfully huge list with all the tree plantations detailed and explained (not in English, though). It's not a difficult challenge but it deals with foreign languages and a subject that's appreciated worldwide.

_________________

To tell you the truth, I haven't solved these questions yet (so I'm taking Miguel at his word that there ARE answers out there).

So let's Search On together!

Friday, December 6, 2013

Answer: Part 2 -- what are the Popo lava domes made of?

Fred pointed out that I left out one of my questions. (This is what comes of trying to get it done by 5PM EST!)

To complete the question about the what the lava domes are made-of, I went to Google Scholar and did the straightforward query:

[ Popocatepetl lava dome ]

And to learn a bit about the lava domes, I skimmed the first three papers. In the third paper (Popocatépetl’s crater filled to the brim: Significance for hazard evaluation) I found the phrase, "dacite lava domes."

Since I had no idea what "dacite" was, I did:

[ define dacite ]

where I learned that dacite is a volcanic rock resembling andesite but containing free quartz.

From Wikipedia I learned that "... Dacite consists mostly of plagioclase feldspar with biotite, hornblende, and pyroxene (augite and/or enstatite). It has quartz as rounded, corroded phenocrysts, or as an element of the ground-mass."

And yes, I looked up all of those words.

But in the end, it's a pretty generic igneous rock spewed from volcanos of this type. It's key feature for lava domes is that it's reasonably plastic, so as gas bubbles up from below, the cooling dacite forms bubbles that appear as domes in the caldera.

And that's what the domes are made of....

Answer: When did the outflow reach the pyramid?

Remember our challenge for this week? It was based on Ramón's photo.

Foto de Ramón.

1. In what year did an outflow from this volcano cover some part of a nearby pyramid that was considered sacred to the rain goddess Chiconauhquiauhitl? (And.. What's the name of the pyramid?)

2. What are the volcanic domes in this caldera made of?

3. Will this volcano erupt again?

To solve this problem I had a bit of a headstart. I knew the photo was from Ramón, and he told me it was of Popocatépetl. But if you didn't know that to start, I would do a modified version of what Owen posted. My first query would have been:

[ volcano Chiconauhquiauhitl ]

My reasoning would be that if there's a temple dedicated to Chiconauhquiauhitl, and that an outflow from the volcano reached it, then there would probably be a web-page with this pair of terms on it. (Keep in mind, that's what you're doing when web-searching; looking for pages with answers that are highly correlated with the key terms of your core question.) And that page would probably tell me the name of the volcano.

Sure enough, that search quickly shows us that the nearby volcano is Popocatépetl (or "Popo" for short). (BTW, here's a link to a page that tells you how to pronounce the proper name of the volcano. Ramón y Juan, does this sound right to you?)

I also knew that it had erupted recently (from my reading of the news). Here's a speeded-up version of the eruption from June, 2013:

So we now have answers to two of the questions: What's the volcano's name? (Popocatépetl) And will it erupt again? Yes, it's active now! (See below for more data on this.)

Now... what about a nearby pyramid? Let's repeat a variation on that first query:

[ pyramid Chiconauhquiauhitl ]

And we discover that it's the Great Pyramid of Cholula. It's the largest archaeological site of a pyramid in the New World, measuring 55 metres (180 ft) above the surrounding plain. In its final form the base was around 400 by 400 metres (1,300 by 1,300 ft).

Interestingly, the pyramid was traditionally viewed as having been dedicated to the god Quetzalcoatl, but more recent discoveries indicate it was actually dedicated to Chiconauhquiauhitl, the godess of the Nine Rains. It was constructed in multiple states, beginning in the 3rd century BCE and work on (and off) throughout until the 9th century CE.

Now that I know where the volcano is, and where the temple is, I can create a map (with a couple of overlay lines showing the shortest path from volcano to temple).

That distance is around 45 km (27.9 miles). As we know from the eruption of Mount St. Helens in 1980, mudflows can easy travel over 50 miles from the volcano center.

So, how can we find out when the last time lava or mud (also called a lahar) flow reached at least 45 km to the east?

Like Rosemary, I first checked out the references at the Wikipedia article, and found what I considered a reputable source via reference #1 (which points to a Smithsonian Museum article).

The Smithsonian Institute Global Volcanism Program has an great website for volcanoes worldwide. Popo's last major eruption happened in 823 A.D. (you can check out the map at http://www.volcano.si.edu/ )

From there, I found a link to Oregon State website showing that last great eruption was 822 A.D. As they say, “Lahars [destructive mudflow] buried the lower 1 meter of the Great Pyramid of Cholula and the Puebla Valley.”

Sounds pretty bad.

Ramón pursued a purely Spanish search strategy (which makes a lot of sense, given that it's in Mexico.) His queries:

[Distancia erupciones Popocatepetl]

[Popo eruption distance]

These queries led to these results (in English):

Potential for Large Eruptions at Popocatepetl -- which also answers the 3rd question (yes, it will erupt again in the near future).

How much pressure did it take to pop the top off Mexico’s Popocatépetl volcano? Shows videos, maps and data based on volcanic plume of June 17, 2013

In Spanish: Áreas de peligro por flujo de material volcánico Areas that could be affected by eruption. Pyramid is in the Moderate risk zone.

In Spanish [desastres naturales piramide cholula] "Natural disasters Cholula Pyramid]
El Popocatepetl y la Legendaria Lluvia de Fuego Mentions "Leyenda de los Soles"

Ramón continues his search with:

[Cholula pyramid eruption history]

Book : Dangerous Neighbors: Volcanoes and Cities - Page 52 Base of Pyramid was buried by volcanic mudflows.

It's worth knowing that Cenapred is the agency that monitors Volcanoes in Mexico ("Center for Prevention of Disasters") They have a timeline of previous Popo eruptions, Historia eruptiva del volcán Popocatépetl , which includes the eruption in the middle 800's.

Photos of the Popo from Cenapred Cameras -- apparently these cameras take pictures whenever anything happens on Popo.

Juan pointed out that "One of the websites that confirmed the 700-850 AD guesstimate was CENAPRED/UNAM Popocatépetl History. 800 AD is obviously not an exact date, but an approximation... the Foundation for the Advancement of Mesoamerican Studies doing a radiocarbon dating shows 700-850 AD results."

For credible resources, Rosemary suggests (and I'm quoting her here):

CEOS (Committee on Earth Observation Satellites) looks like a huge conglomeration of agencies coming together to utilize satellites for environmental observations. It has a section specific to volcanoes and lists projects involved with CEOS for monitoring geo-hazards.

Along with these projects we can gather the names of various people, institutes and agencies involved such as USGS, NOAA, NASA, along with several agencies worldwide. For the purposes of credibility it helps to identify key names related to our subject that in turn can lead us to other sites and support our findings.

When I think of credibility I immediately think of Google Scholar. However when dealing with such a technical and complex subject such as volcano composition, structure and eruptions, I find it easy to get swallowed up when viewing intellectual papers. For me knowing how to glean useful information for our searches from in-depth papers would be quite beneficial.

And I agree. Typically, Scholar will have very good resources, but it might take some time to collect, organize, read (and look up all the words you don't know).

We'll return to this topic in the future, as it's a critical skill for advanced search research.

Search Lessons: As Ramón pointed out, searching in the local language can often reveal sources that aren't otherwise available. That's an incredibly handy thing to know when you're searching for international content.

Second, bridging searches (as I did when I searched for [volcano Chiconauhquiauhitl ] and then searched for the nearby pyramid to get from volcano to pyramid name) is another good strategy. Often complex searches come in pieces. "Bridging" to find one piece in common (the name of the volcano) then "unlocks" all of the other search steps and lets you figure it all out together.

Finally, as I've said before, "credible" resources are largely based on sites you know and trust. Having multiple sources for a piece of information (e.g., the date the pyramid had the lahar mud flow up and onto the doorstep) is a good thing to do. Pay attention to the publishing institution (e.g., Oregon State) and verify that they actually DO volcano studies by looking for the institution's web site.

Knowing the name of the institution is a good thing, but be sure they actually know what they're talking about!

With that...

Search on! Credibly!

Thursday, December 5, 2013

Not an answer... yet: When did the outflow reach the pyramid?

It looks a bit like the volcano is harder than I thought it would be!

Usually, by this point, we have 10 or 12 comments. Maybe it's just the December slows that are holding people back. But in any case, I'll keep this challenge open for another day, just to see if we'll get any more comments / answers.

As many people found, it's easy to get answers, but it's harder to judge credibility. This is especially true for areas where you're not already an expert. I know a bit about volcanos, but I'm scarcely a vulcanologist. This happens a lot ("you're not an expert in <topic>"), especially with medical and health search problems.

So we're left trying to figure out when a resource is credible or not. This is a long discussion, but for this discussion we'll focus on known and respected agencies.

For volcanos, the USGS (United States Geological Survey) is a well-known (and trusted) source. Well-known universities (several people mentioned Oregon State University) are good resources... but it's worth a few seconds to verify that they actually have some depth in the topic. (It only took me 1 minute to verify that they have a College of Earth, Ocean, and Atmospheric Sciences, with a specialty in volcanos.)

I'll leave it as an exercise for you to find the Mexican equivalent of the government body that studies geological (and vulcanological) issues! My point is that there are many organizations with points of view about this volcano--be sure your data is coming from a source you believe!

Search on!

(Answer tomorrow.)

A recent eruption of this volcano...
Image linked from the Guardian (UK).

Wednesday, December 4, 2013

Wednesday search challenge (12/4/13): When did the outflow reach the pyramid?

Last night a bunch of us had a meet-up in Silver Spring (Maryland) and got to chatting about SearchResearch. If you’ve read this blog for a while now, you know that not everyone is local to Maryland, so it’s not a surprise that we started talking about other regular contributors. Ramón is often among the first responders to the weekly search challenges, and last night I mentioned that he had recently sent me a beautiful photo of a mountain not far from where he lives.

Naturally, this made me think of today’s search challenge. Photo credit to Ramón for this pic (and for the inspiration to write this challenge).

This isn’t just ANY old mountain, it’s a beautiful, and potentially deadly, volcano somewhere south of California. (Juan will probably recognize it instantly as well.) The rest of us will have to search it out and answer the following challenges: