This is a picture of a geologist examining the eruptive hsitory of a volcano.
Click on image for full size
Image from: U.S. Geological Survey, photo by Robert McGimsey

Eruption Layers

This is a picture of a geologist examining the lava flows of a volcano.


You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Magma Chamber

When magma is erupted onto the surface in the form of lava, it becomes silicate rock. With each different eruption of the volcano, lava which comes to the surface is made of slightly different chemicals,...more

Volcanic Ash

Ash is formed as a volcano erupts when rocks made by the volcano blow apart into millions of tiny pieces. The rocks are still very hot, because they just formed from lava. If the hot rocks come into contact...more

Cinder Cones

Cinder cones are simple volcanoes which have a cone shape and are not very big. Compare the size of this volcano to the strato-volcano in this image. They are usually made of piles of lava, not ash. During...more

Flowing Lava

Lava can move in two ways, wide flat lava flows, or through channels which squeeze the lava into a small area. The fastest lava flows move at about 6 mi/hr, an easy jog, but they average between 2/3 and...more

How Do Plates Move?

Plates at our planet’s surface move because heat in the Earth’s core causes molten rock in the mantle layer to flow. We used to think the Earth’s plates just surfed on top of the moving mantle, but now...more

Clues to Plate Movements

Many kinds of surface features are clues to a sliding lithosphere. Two types of features can form when plates move apart. At ocean ridges, the crust splits apart to make room for molten mantle rock. Continental...more

Mid-Ocean Spreading Ridge

As the Earth cools, hot material from the deep interior rises to the surface. Hot material is red in this drawing, under an ocean shown in blue green. The hotter material raises the nearby layers, and...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA