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The Spring 2011 issue of The Earth Scientist is focused on modernizing seismology education. Thanks to IRIS, you can download this issue for free as a pdf. Print copies are available in our online store.

Earth's Interior and Surface

Earth, the largest rocky planet, was formed about 4.5 billion years ago. The Earth's interior is divided into four layers which is typical of rocky planets. It is cool on the surface but very hot deep inside the planet. The center, or core, is as hot as 9000 degrees F.

The Earth's surface is unique from the other planets because it is the only one with liquid water. Water helps to make surface features such as rivers, lakes and oceans. The moving plates of the Earthís surface form other surface features such as mountains, earthquakes and volcanoes.

This is the Barringer Meteor Crater in Arizona. The diameter is 1.2
  kilomters, and it is 49,000 years old. Compared with other planets, <a
  href="/earth/Interior_Structure/crater.html&edu=elem">impact
  craters</a> are rare <a
  href="/earth/Interior_Structure/surface_features.html&edu=elem">surface
  features</a> on Earth. There are two main reasons for the low number of
  craters. One is that our <a
  href="/earth/Atmosphere/overview.html&edu=elem">atmosphere</a>
  burns up most <a
  href="/our_solar_system/meteors/meteors.html&edu=elem">meteoroids</a>
  before they reach the surface. The other reason is that Earth's surface is <a
  href="/earth/interior/plate_tectonics.html&edu=elem">continually
  active</a> and erases the marks of craters over time.<p><small><em>D. Roddy and LPI</em></small></p>Sinkholes are <a href="/teacher_resources/main/frameworks/esl_bi8.html&edu=elem">natural hazards</a> in many places around the world. They are formed when water dissolves underlying <a href="/earth/Water/carbonates.html&edu=elem">limestone</a>, leading to collapse of the surface.  Hydrologic conditions such as a lack of rainfall, lowered water levels, or excessive rainfall can all contribute to sinkhole development. On 2/28/2013, a sinkhole suddenly developed under the house outside of Tampa, Florida, leading to the tragic death of its occupant, Jeff Bush.<p><small><em>Image courtesy of Southwest Florida Water Management District</em></small></p>An <a href="http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc000905e.php">8.6 magnitude earthquake</a> struck on 11 April 2012 off of Banda Aceh, Sumatra, Indonesia, followed by a strong aftershock.  Earthquake motion was primarily horizontal.  A tsunami warning was issued for the Indian Ocean, but was cancelled at 12:36 UTC.  A tsunami was observed at 1 meter or less. Find out more about <a href="/earth/geology/quake_1.html&edu=elem">earthquake</a> and <a href="/earth/tsunami1.html&edu=elem">tsunami</a> processes. Check out the resources <a href="/teacher_resources/2011_AGU-NESTA_GIFT_Workshop.html&edu=elem">here</a>.<p><small><em>NOAA</em></small></p>

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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