958 Volcanoes and 2.6 Billion Neighbours (Live Smithsonian Data)
We tend to picture a volcano as a remote thing: a lonely cone in Iceland, a smoking peak on an empty island. The data tells a very different story. We loaded the Smithsonian’s Global Volcanism Program catalogue of Holocene volcanoes, every volcano known to have erupted in roughly the last 12,000 years, into a public dataset on QuantumLayers and started asking who actually lives near them. The answer is startling: across these 958 volcanoes, more than 2.6 billion people live within 100 kilometres of one.
The dataset is marked public, and every chart below is drawn live. When this page loads, your browser calls QuantumLayers’ public chart endpoint and renders whatever the dataset currently holds, with no API key, no login, and no hard-coded numbers. Each figure also links to its own standalone ql-chart page on QuantumLayers, so you can open it, change it, and take it apart yourself.
The most crowded volcanoes on Earth
Start with the extremes. If you rank every volcano by how many people live within 100 kilometres, the top of the list is not in some distant wilderness. It is on Java. Gede-Pangrango, a stratovolcano within reach of greater Jakarta, has more than 40 million people in that radius, and the next several places on the list are its Indonesian and Mexican neighbours. These are not obscure mountains. They sit on the doorstep of some of the densest urban regions on the planet.
Figure 1: The ten volcanoes with the most people living within 100 km, fetched live from QuantumLayers and sorted in your browser. Source: Smithsonian GVP.
▶ Open the live ql-chart on QuantumLayers
That crowding is not a rare accident either. Nearly four in ten of the volcanoes in the catalogue have more than a million people within 100 kilometres, and 58 of them clear ten million. Living in the shadow of a volcano is, statistically, an ordinary thing to do.
Where they cluster: a handful of countries hold most of them
Volcanoes are not sprinkled evenly around the globe. They trace the seams where tectonic plates meet, and that geography stacks them up in a short list of countries. The United States, Indonesia and Japan alone account for close to a third of the entire catalogue, and once you add Russia and Chile you have most of the Pacific “Ring of Fire” in five names.
Figure 2: Share of catalogued volcanoes by country, top nine, fetched live. Source: Smithsonian GVP.
▶ Open the live ql-chart on QuantumLayers
Most of them are the same shape
Ask someone to draw a volcano and they will almost certainly draw a stratovolcano: the classic steep-sided cone of Fuji or Mayon. The catalogue confirms the stereotype. Stratovolcanoes and their close variants are by far the most common single type on record, well ahead of the broad, gently sloping shields, the pockmarked volcanic fields, and the collapsed calderas that make up the rest.
Figure 3: Share of volcanoes by primary type, top eight, fetched live. Source: Smithsonian GVP.
▶ Open the live ql-chart on QuantumLayers
Does height keep people away? Barely
You might expect the tallest, most forbidding volcanoes to be the emptiest, and the low ones to be the crowded ones. Plotting every volcano’s elevation against the population within 100 kilometres puts that intuition to the test. The cloud of points drifts upward only very slightly: QuantumLayers measures the correlation at just r = 0.16, a weak positive link. Height barely predicts crowding at all. The 6,000 metre giants of the Andes can be nearly deserted, while a modest 3,000 metre cone on Java sits under tens of millions of people. What fills the ground around a volcano is human geography, not altitude.
Figure 4: Elevation versus population within 100 km, one point per volcano, fetched live. Source: Smithsonian GVP.
▶ Open the live ql-chart on QuantumLayers
What the statistics reveal
Charts show the shape; the statistics pin it down. We ran QuantumLayers’ automated statistical analysis across the numeric columns in the dataset, testing distributions, outliers and group effects. Three findings stood out.
Most volcanoes are quiet neighbours, and a few are enormous ones. The median volcano has about 355,000 people within 100 kilometres, and the middle half of the catalogue ranges from roughly 11,000 to 3 million. But the distribution is violently lopsided, with a skewness of 3.4, because a short tail of megacity volcanoes runs all the way up to Gede-Pangrango’s 40.6 million. QuantumLayers flagged the nearby-population figures as heavily outlier-driven; here that is not bad data, it is the difference between a volcano in the Aleutians and one beside Jakarta.
▶ Open the live ql-chart on QuantumLayers
The type of volcano really does track its height. QuantumLayers’ analysis of variance found that a volcano’s primary type has a large, highly significant effect on its elevation (η² ≈ 0.17, p < 0.0001). This is not a labelling quirk, it is geology: towering stratovolcanoes are built tall by repeated eruptions of sticky lava, while low shields, fields and cones form in entirely different ways. The name of the shape and the number on the altimeter are telling the same story.
Where a volcano sits still shapes how crowded it is. Country has an overwhelming effect on nearby population in the analysis, a large and highly significant group effect across every population radius. Read plainly, that is a restatement of the human stakes: the hazard a volcano poses is set as much by the nation and the cities that grew up around it as by the mountain itself. The volcano supplies the rock; people supply the risk.
How this was built
No spreadsheets, no manual downloads. The Smithsonian catalogue was connected as a public dataset in QuantumLayers, which ingested and typed every column. Each chart above is rendered with Chart.js, populated at page load by a single POST to QuantumLayers’ ql_get_chart_data endpoint. Because the dataset is public, that call needs no authentication: the browser gets back a ready-to-draw Chart.js config and paints it. The “Open the live ql-chart” links point at QuantumLayers’ hosted ql-chart page, which renders the same visualization from nothing but URL parameters. Want a different cut, volcano types by country, elevation by tectonic setting, a map of every summit? The data is public; go explore.
Data: Smithsonian Institution, Global Volcanism Program, Holocene volcano catalogue (via the TidyTuesday open-data project). Counts and population figures reflect the dataset at request time.
This article is part of an ongoing series in which we analyze public datasets using QuantumLayers, our own data-analysis platform. Each post takes an openly available dataset, loads it into QuantumLayers, and shares what the charts and statistics reveal.
