describe the global spatial distribution of volcanoes

Volcanoes are not randomly distributed over the Earth's surface. They are found mostly along tectonic plate boundaries, and especially on the Pacific Plate, where it's known as the "Ring of Fire". This area is home to 75% of the world's active volcanoes.

1. Ring of Fire: This is the major area in the basin of the Pacific Ocean where a large number of earthquakes and volcanic eruptions occur. It includes several countries like Japan, Philippines, New Zealand, Canada, and the USA (State of California).

2. Mid-Atlantic Ridge: This is a divergent tectonic plate boundary located along the floor of the Atlantic Ocean, and it partakes in the formation of new oceanic crust, which can result in volcanic activity. Iceland is a part of the Mid-Atlantic Ridge.

3. African Rift Valley: This is a divergent plate boundary that is pulling apart, causing the formation of a rift valley. This area is known for its volcanic activity, with Mount Kilimanjaro being a notable example.

4. Mediterranean: There are several active volcanoes in the Mediterranean area, including Mount Etna and Stromboli in Italy, and Santorini in Greece.

5. Hawaii and other Oceanic Islands: These are formed by hotspots, which are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the mantle elsewhere. The Hawaiian island chain are examples of hotspot volcanoes.

In summary, the global spatial distribution of volcanoes is primarily along the tectonic plate boundaries, with the majority located in the Pacific Ring of Fire.