Introduction to Seismology

Seismology = The study of the earth science study of earthquakes Seismologists = The scientists who study earthquakes and the hazards Seismograph = The instrument that detects and records ground motion Seismograms = The graphical output of the seismograph

Magnitude = A measure of the energy released from an earthquake Scale = The method for expressing the magnitude using the Richter Scale Foreshocks = Tremors that occur before the main earthquake Aftershocks = Weaker earthquakes that follow the main shocks

Before Earthquakes = Familiarize yourself with earthquake hazards in your areas During Earthquakes = Cover - Hold on - Drop After Earthquakes = Evacuate as soon as the shaking stops If outside = Move to an open area

<p>Ground shaking = The primary hazard during an earthquake Ground rupture = A physical break in the earth's surface Aftershocks = Weaker tremors that follow the main quake Foreshocks = Smaller tremors that precede the main quake</p> Signup and view all the answers

<p>If inside a moving vehicle = Stop and remain inside the vehicle If near a shore = Move quickly to higher ground If inside a building = Drop, cover, and hold on If near a steep slope = Move away from it</p> Signup and view all the answers

<p>A lahar is a wet mixture of volcanic material and water, which can flow rapidly and carry additional volcanic debris, unlike a typical lava flow that is primarily molten rock.</p> Signup and view all the answers

<p>Surviving a lahar inundation is nearly impossible due to its swift movement, reaching speeds of 10 meters per second, and the density of volcanic materials it carries.</p> Signup and view all the answers

<p>Ashfall consists of volcanic particles smaller than 2 mm and can cause severe health problems, including respiratory issues and skin diseases when it contaminates water.</p> Signup and view all the answers

<p>Gravity is a key factor in the movement of lahars, forcing them to flow downwards, which influences their speed and path.</p> Signup and view all the answers

<p>Lahars can form independently through rainfall or thunderstorms that trigger the flowing of volcanic material, not just from volcanic eruptions.</p> Signup and view all the answers

<p>A lahar consists of a wet mixture of volcanic material and water, which can include pyroclastic flow and tephra.</p> Signup and view all the answers

<p>Ashfall can lead to health risks such as respiratory issues and severe skin diseases from contaminated water, due to its toxic nature.</p> Signup and view all the answers

<p>Lahars can form from volcanic eruptions, rainfall, or thunderstorms, while typical lava flows specifically result from molten rock from an eruption.</p> Signup and view all the answers

<p>Lahars can move at speeds of up to 10 meters per second, making them nearly impossible to outrun for anyone in their path.</p> Signup and view all the answers

<p>Lahars can submerge and destroy structures, bringing toxic materials that contaminate soil and water, affecting the environment significantly.</p> Signup and view all the answers

<p>Seismologists study earthquakes and assess their associated hazards.</p> Signup and view all the answers

<p>The Richter Scale measures the magnitude of an earthquake, quantifying the energy released at the source.</p> Signup and view all the answers

<p>Foreshocks are smaller tremors that occur before the main earthquake, indicating potential seismic activity.</p> Signup and view all the answers

<p>You should cover, hold on, and drop to protect yourself from falling debris.</p> Signup and view all the answers

<p>You should evacuate safely, check for injuries, and prepare for potential aftershocks.</p> Signup and view all the answers