Seismic Waves Shadow Zones

Geographical explanation: Hills, mountains, plateaus, valleys, etc. are the landforms we see on the earth’s surface. They have been developed and shaped by the internal and external forces. The internal processes are classified into slow movements and sudden movements. The earth’s surface changes slowly but continuously.

The event depicted in photo 2 is related to the slow or sudden processes operating within the earth's crust.

P-waves, S-waves, and longitudinal waves

<p>A region on the Earth's surface where seismic waves of an earthquake are not reported.</p> Signup and view all the answers

<p>P-waves</p> Signup and view all the answers

<p>Due to the presence of a shadow zone on the Earth's surface.</p> Signup and view all the answers

<p>Between 105° and 140° away from the epicentre</p> Signup and view all the answers

<p>S-waves</p> Signup and view all the answers

<p>To connect places with uniform intensity of earthquake</p> Signup and view all the answers

<p>The Mercalli scale describes intensity based on observed effects, while the Richter scale measures magnitude using seismic waves</p> Signup and view all the answers

<p>Active, dormant, extinct</p> Signup and view all the answers

<p>Magma is molten rock material below the earth's surface, while lava is the same material when it appears on the surface.</p> Signup and view all the answers

<p>Acidic lava contains a higher percentage of silica, has a high melting point, is thick, fluid, and moves slowly.</p> Signup and view all the answers

<p>The largest recorded explosion on August 28, 1883 caused the entire island of Krakatoa to disappear.</p> Signup and view all the answers