Generate volcano trivia with this SQLite tutorial

Excel is not a database. Even so, spreadsheets are commonly used as such. They are convenient places to enter and store data, but not to get it out again. This post aims to show how using a real database makes this easier.

It uses an SQLite database, which is what many browsers (e.g. Firefox) use to store your bookmarks and history. These can also be read by other software e.g. Geographic Information Systems. It has none of the overly-complex wrappings of MS Access or LibreOffice Base and doesn’t need a server like MySQL or Oracle. Once the data are imported, typically from a comma separated value (csv) file, it simply provides an interface so that we can ask questions using Structured Query Language (SQL).

This example uses the Smithsonian Institute’s Global Volcanism Program catalogue of volcanoes, which can be downloaded as a csv file from their website, as the database.  It lists locations and recent eruptions of over 1,500 active volcanoes. Querying the list can generate a wealth of interesting (and less-interesting) volcano facts.

The commands may look complicated at first, but hopefully you can see where the advantages in a real database lie.  If so, there are instructions for getting started at the end.  If not, just enjoy the trivia.

Get an A-Z list of all the volcanoes in the world.

SELECT "Volcano Name" FROM GVPVolcano
ORDER BY "Volcano Name";
Volcano name
Abu
Babuyan Claro
Cabalían
Dabbahu
E-san
Falcon Island
Gabillema
Hachijo-jima
Iamalele
Jailolo
Kaba
La Palma
Ma Alalta
NW Eifuku
O’a Caldera
Pacaya
Qal’eh Hasan Ali
Rabaul
SW Usangu Basin
Ta’u
Ubehebe Craters
Vailulu’u
Waesche
Xianjindao
Yake-dake
Zacate Grande, Isla

The database contains information on 1555 volcanoes. That’s a big spreadsheet to manipulate by hand. This list is trimmed to give just the first example for each letter of the alphabet. There are 160 volcanoes whose name begins with ‘S’, but only one that begins with ‘X’ (Xianjindo in North Korea).

Get a list of all the volcanoes in Iceland.

SELECT "Volcano Name" FROM GVPVolcano
  WHERE "Country" IS "Iceland";
Volcano Name
Snaefellsjökull
Helgrindur
Ljósufjöll
Reykjanes
Krísuvík
Brennisteinsfjöll
Hengill
Hrómundartindur
Grímsnes
Prestahnukur
Hveravellir
Hofsjökull
Vestmannaeyjar
Eyjafjallajökull
Katla
Tindfjallajökull
Torfajökull
Hekla
Grímsvötn
Bárdarbunga
Tungnafellsjökull
Kverkfjöll
Askja
Fremrinamur
Krafla
Theistareykjarbunga
Tjörnes Fracture Zone
Öraefajökull
Esjufjöll
Kolbeinsey Ridge

If you wanted to plot them on a map, you can get their latitude and longitude, too.

SELECT "Volcano Name", Longitude, Latitude FROM GVPVolcano
  WHERE "Country" IS "Iceland";
Volcano Name Longitude Latitude
Snaefellsjökull -23.78 64.8
Helgrindur -23.25 64.87
Ljósufjöll -22.23 64.87
Reykjanes -22.5 63.88
Krísuvík -22.1 63.93
Brennisteinsfjöll -21.83 63.92
Hengill -21.32 64.08
Hrómundartindur -21.202 64.073
Grímsnes -20.87 64.03
Prestahnukur -20.58 64.6
Hveravellir -19.98 64.75
Hofsjökull -18.92 64.78
Vestmannaeyjar -20.28 63.43
Eyjafjallajökull -19.62 63.63
Katla -19.05 63.63
Tindfjallajökull -19.57 63.78
Torfajökull -19.17 63.92
Hekla -19.7 63.98
Grímsvötn -17.33 64.42
Bárdarbunga -17.53 64.63
Tungnafellsjökull -17.92 64.73
Kverkfjöll -16.72 64.65
Askja -16.75 65.03
Fremrinamur -16.65 65.43
Krafla -16.78 65.73
Theistareykjarbunga -16.83 65.88
Tjörnes Fracture Zone -17.1 66.3
Öraefajökull -16.65 64.0
Esjufjöll -16.65 64.27
kolbeinsey ridge -18.5 66.67

What can you tell me about Hekla?

SELECT * FROM GVPVolcano
 WHERE "Volcano Name" IS "Hekla";

There isn’t room to show all the columns as a table, but the data look like:

Volcano Number = 372070
Volcano Name = Hekla
Country = Iceland
Primary Volcano Type = Stratovolcano
Last Known Eruption = 2000 CE
Region = Iceland and Arctic Ocean
Subregion = Iceland (southern)
Latitude = 63.98
Longitude = -19.7
Elevation (m) = 1491.0
Dominant Rock Type = Andesite / Basaltic Andesite
Tectonic Setting = Tensional Oceanic

Which is taller, Mt Fiji or Mt Etna?

SELECT "Volcano Name", "Elevation (m)" FROM GVPVolcano
  WHERE "Volcano Name" is "Fuji"
  OR "Volcano Name" IS "Etna";
Volcano Name Elevation (m)
Etna 3330.0
Fuji 3776.0

Fuji wins! But Etna has been trying hard to catch up recently.

What are the 10 tallest volcanoes in the world?

SELECT "Volcano Name", Country, "Elevation (m)" FROM GVPVolcano
WHERE "Elevation (m)" IS NOT "NaN"
ORDER BY "Elevation (m)" DESC
LIMIT 10;
Volcano Name Country Elevation (m)
Ojos del Salado, Nevados Chile-Argentina 6887.0
Llullaillaco Chile-Argentina 6739.0
Tipas Argentina 6660.0
Incahuasi, Nevado de Chile-Argentina 6621.0
Cóndor, Cerro el Argentina 6532.0
Coropuna Peru 6377.0
Parinacota Chile-Bolivia 6348.0
Chimborazo Ecuador 6310.0
Pular Chile 6233.0
Solo, El Chile-Argentina 6190.0

They are all in western South America. I suppose that this region has the advantage of the Pacific plate being subducted under the South American continent and pushing up the Andes mountain range. The volcanoes just sit on top of it. This highlights the issue that your definition of the tallest may depend on where you are measuring from. Sea level, the Earth’s crust, the centre of the Earth? This video from BBC Planet Earth Unplugged explains this nicely.

Ojos de Salados, on the Chile-Argentina border, is 6888 m tall and last erupted around 700 AD. Source: http://volcano.si.edu/volcano.cfm?vn=355130

What are the 5 northernmost volcanoes in the world?

SELECT "Volcano Name", Country, Latitude, "Tectonic Setting" 
 FROM GVPVolcano
 ORDER BY Latitude DESC
 LIMIT 5;
Volcano Name Country Latitude Tectonic Setting
Unnamed Undersea Features 88.27 Tensional Oceanic
Unnamed Undersea Features 85.58 Tensional Oceanic
Jan Mayen Norway 71.08 Tensional Oceanic
Kolbeinsey Ridge Iceland 66.67 Tensional Oceanic
Tjörnes Fracture Zone Iceland 66.3 Tensional Oceanic

They all relate to the mid-ocean ridges, whereas the southern ones are all in Antarctica and are relate to subduction. There are no active volcanoes within 1,100 km of the South Pole.

Volcano Name Country Latitude Tectonic Setting
Morning, Mt. Antarctica -78.5 Intermediate Continental
Royal Society Range Antarctica -78.25 Intermediate Continental
Erebus Antarctica -77.53 Intermediate Continental
Waesche Antarctica -77.17 Intermediate Continental
Unnamed Antarctica -76.83 Intermediate Continental

Mount Morning, Antarctica, is the southernmost volcano in the world. Source: http://volcano.si.edu/volcano.cfm?vn=390017

What are the most volcanically active countries in the world?

SELECT Country, COUNT(Country) AS NumberOfVolcanoes FROM GVPVolcano
  GROUP BY Country
  ORDER BY NumberOfVolcanoes DESC
  LIMIT 5;
Country NumberOfVolcanoes
United States 184
Russia 154
Indonesia 142
Japan 114
Chile 78

If you stood all the volcanoes in the world on top of each other, could you reach the Moon?

SELECT SUM("Elevation (m)") AS TotalHeight FROM GVPVolcano;
TotalHeight
2533877.0

Not even close! 2,534 km is nothing compared to the 384,000 km distance to the Moon. It isn’t even a tenth as high as the orbits of geostationary satellites (36,000 km).

Which volcanoes have erupted since I was born?

You have to be a little bit tricky with this, as the eruption years in the database are in the form “2013 CE”, so you have to trim off the spare text and tell SQLite to treat it as a number (integer).

SELECT CAST(TRIM("Last Known Eruption", " CE") AS integer) AS Year, 
 "Volcano Name", Country FROM GVPVolcano
WHERE "Last Known Eruption" LIKE "% CE"
AND Year >= 1979
ORDER BY Year;
Year Volcano Name Country
1979 Curacoa Tonga
1979 Carrán-Los Venados Chile
1979 Arenales Chile
1979 Lautaro Chile
1979 Soufrière St. Vincent Saint Vincent and the Grenadines
1980 Kuchinoerabujima Japan
1980 On-take Japan
1980 Callaqui Chile
1981 Okataina New Zealand
1981 Shikotsu Japan
1981 Chachadake [Tiatia] Japan – administered by Russia
1982 Chirpoi Russia
1982 Chichón, El Mexico
1982 Wolf Ecuador
1983 Colo [Una Una] Indonesia
1983 Kusatsu-Shirane Japan
1984 Galunggung Indonesia
1984 Kaitoku Seamount Japan
1984 Mauna Loa United States
1984 Krafla Iceland
etc.

There were 273 of them, apparently. The database only lists the most recent eruption of each volcano, so Mt St Helens appears in 2008, and not 1980 in the snippet above. 57 volcanoes registered eruptions in 2013.

How many volcanoes are in the poorest countries of the world?

The real power of SQL comes from combining data from different tables. In this example, we use a list of the countries with Gross Domestic Product per Capita of less than $5,000 from the CIA World Factbook as a filter for volcanically-active countries. If you weren’t just doing this for fun, you’d need to check that all the country names are identical in the two tables.

SELECT COUNT("Volcano Name") AS NumOfCountries FROM GVPVolcano
WHERE Country IN (SELECT Country FROM CIAFactbook
WHERE "GDP - per capita (PPP)" < 5000);
NumOfCountries
482

So 482 of the 1555 active volcanoes are in the poorest 88 of the 261 countries in the CIA Factbook.

Which countries have the most volcanoes per head?

This example uses a JOIN.  JOINs are extremely powerful when you have data of different types in different tables. The number of volcanoes per head is very small, so citizens per volcano is presented here instead.

SELECT v.Country, 
 COUNT(v.Country) AS NumberOfVolcanoes,
 c.Population,
 c.Population / COUNT(v.Country)*1.0 AS CitizensPerVolcano
FROM GVPVolcano AS v
LEFT JOIN CIAFactbook AS c
ON v.Country=c.Country
WHERE Population IS NOT Null
  GROUP BY v.Country
  ORDER BY CitizensPerVolcano ASC
  LIMIT 5;
Country NumberOfVolcanoes Population CitizensPerVolcano
Tonga 18 120898 6716
Iceland 30 306694 10223
Dominica 5 72660 14532
Vanuatu 14 218519 15608
Saint Kitts and Nevis 2 40131 20065

The join works by matching the Countries column in each of the two tables. Unsurprisingly, I suppose, it turns out that volcanic island nations are the places where people live closest to active volcanoes.

A practical example for geologists

Another purpose of this post is to demonstrate how scientists can benefit from using databases in their work. As a geologist, I need to keep track of samples collected from the field and the results that I get from analysing them. A suitable database might contain the following tables with the following columns:

  • Site: Number, Latitude, Longitude
  • Sample: Number, SiteNumber, Type (e.g. lava, ash), Description
  • XRFData: SampleNumber, SiO2, Al2O3, NaO, K2O, …

The idea is that each table contains only one type of data and that each has one key column with unique values (e.g. site or sample numbers). You can then get your data with short queries.

For example, chemical composition data from the XRF instrument is commonly plotted on a ‘Total alkalis vs silica’ plot, which distinguishes between different magma types (e.g. basalt, andesite). You can extract the data with:

SELECT SampleNumber, 
  NaO+K2O AS TotalAlkali, 
  SiO AS Silica 
FROM XRFData;

To plot a map of SiO2 content in lava samples you can join the tables together.

SELECT Sample.Number, 
  Site.Latitude, 
  Site.Longitude, 
  XRFData.SiO2
FROM Sample
  LEFT JOIN Site ON Sample.SiteNumber=Site.Number
  LEFT JOIN XRFData ON Sample.Number=XRFData.SampleNumber
WHERE Site.Type IS 'lava';

If you do more analysis, you can simply add another table (e.g. SieveData, LiteratureData) without having to mess around with the data that you already have and, as long as your sample numbers are distinct, you can keep data from different projects together instead of scattered across many spreadsheets.

Getting started

There are two good programs for viewing SQLite databases. Both are free+open source software, so you can download and install them on as many machines as you like. SQLite Manager is an add-on for the Firefox web browser. It has a nice tool for importing data from csv files. Sqliteman is a small stand-alone package that runs on Linux (sudo apt-get install sqliteman on Ubuntu-like systems), Windows or Mac. There is also a command-line interface utility, sqlite3 that can import and export data.

Click here to download the SQLite file for the database used in this post. It includes data from the Smithsonian Institute’s Global Volcanism Program’s volcano spreadsheet and csv version of the CIA World Factbook from here.

I highly recommend the W3 Schools’ SQL tutorial for learning the language. It takes about an hour. It is also worth reading up on database structure, particularly normalization, to help you choose suitable tables.

Regular readers of volcan01010 may be surprised that I have got this far without mentioning Python, a free+open source programming language that is becoming central to a scientist’s toolbox. The sqlite3 module comes as standard and lets Python read and write directly from / to SQLite databases. The Zetcode SQLite Python tutorial gives a great introduction.  It’s often easiest to input and edit data as csv files and it’s straightforward to write a Python script to automatically import them as tables for analysis. As csv files are plain text, they are easily portable and can also be tracked with version control software.

Happy databasing…

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