Earthquakes and Volcanoes Engage Watch a video on

Earthquakes and Volcanoes

Engage Watch a video on Earthquakes in California – You tube- search California Earthquake and there are several short videos https: //www. youtube. com/attributio n_link? a=ccg. UWk. Ms 4 Rjnt 3 fm&u=/watc h%3 Fv%3 DFWTkpv. KPl 0%26 feature%3 Demshare_video_user

Explore Journal- Write down what you know about Earthquakes. Brain Pop- Earthquake Assign notes and vocab

Explain- What are Earthquakes? An earthquake is the violent shaking of the ground caused by the movements of Earth’s tectonic plates. Most earthquakes occur along fault lines, which is where two tectonic plates come together.

Tectonic Plates

Earthquake Occur at plate boundaries As plates move, their edges experience immense pressure. Stress becomes so great, that it breaks rock along a fault line. Energy is released as seismic waves that travel through the Earth, creating the shaking that we experience.

Earthquakes occur mostly at the boundaries of tectonic plates

The Focus and Epicenter of an Earthquake • The point within Earth where faulting begins is the focus, or hypocenter • The point directly above the focus on the surface is the epicenter

Earthquake waves travel in all directions from the focus.

Energy from earthquakes is transferred by waves The energy released by an earthquake is measures as shock waves P waves also called longitudinal wave originate from an earthquake's focus. They travel fast and first to reach recording stations. P waves stretch the Earth’s crust like pulling A slinky back and letting go

S waves also called transverse wave or secondary waves, they move more slowly. S waves are like shaking a slinky up and down

Surface Waves: R and L waves Surface Waves Travel just below or along the ground’s surface Slower than body waves; rolling and side-toside movement Especially damaging to buildings

Measuring earthquakes Scientists measure waves to learn about earthquakes. Seismographs are used to record data by measuring ground motion during an earthquake

How is an Earthquake's Epicenter located? There are more then 1000 seismograph stations across the world At each station, 3 seismographs are used to measure different motions, north and south, east and west, and up and down. P waves are first to be recorded, followed by S waves

Locating the Epicenter The difference in time between the arrival of the P and S waves enables seismologists to calculate the distance between the station and the focus of the Earthquake. When the distance between 3 stations are calculated, 3 circles can be drawn on a map and the epicenter is where all 3 connect.

Richter Scale a measure of the energy releases by an earthquake Each step on the Richter scale represents a 30 -fold increase in the energy released ex. An earthquake of magnitute 8 releases 810, 000 times as much energy as one of magnitude 4!

Richter Scale

Moment Magnitude Scale Most widely used today Measures how much energy is released

How Severe will the damage be? The Richter Scale can not predict how severe and Earthquake will be. The amount of damage depends on several factors such as the distance between populated areas and the epicenter and what time of soil and rock

Damage San Francisco 1989 Armenia 1988 Magnitude 7 70 people dead 25, 000 dead Rock is harder Rock/soil very soft Focus was 19 km down Focus was 5 km down

The_______is the meausre of energy released by an earthquake? A. Magnitude B. Richter Scale C. Epicenter D. Focus E. None of the above

Is the exact point inside the Earth where an Earthquake originates A. Magnitude B. Richter Scale C. Epicenter D. Focus E. None of the above

The point on the surface where immediately above the focus is called the? A. Magnitude B. Richter Scale C. Epicenter D. Focus E. None of the above

Which type of wave travels up and down? A. Surface Wave B. S wave or secondary wave/ transverse C. P Wave or Longitudinal D. Richter Scale E. Seismology

Elaborate Gizmo- Earthquakes 1 - Recording Station Earthquake shaking hazards in the USHave them color all the same and then write a paragraph on the back about what information the picture shows

Evaluate Page 717 - questions 1 and 4

Volcanoes

Engage Find a short video on You tube showing a volcano erupting

Explore Journal- Write what you know about volcanoes Brain pop- Volcano Assign Notes and Vocab

Explain- Volcanoes vent Volcanoes are openings in the Earth’s surface. When they are active they can let ash, gas, and hot magma escape in sometimes violent and spectacular eruptions magma chamber

Volcanoes Form hills or mountains as materials pour or explode from the vent

Volcanoes Generally have one central vent, but may have several smaller vents. Magma from inside the volcano can reach Earth’s surface though vents, and is then called lava.

Shield Volcanoes Shield volcanoes have magma rich in iron and magnesium which is very fuild Forms lava that tends to flow great distances The build up of this lava creates a gently sloping mountain Largest volcanoes- Mauna loa- Hawaii 13, 000 feet

Composite Volcanoes are made up of Alternating layers of ask, cinders, and lava Their magma is rich in silica and is much for viscous (thick) then magma from a shield volcano Gas is trapped in the magma which cause eruptions that alternate with flows of lava and explosions of cinder and ash Steep slopes and really tall- Mt. St. Helens, Mount Rainer

The ask can travels for 1000’s of miles When Mt. St. helens erupeted in the 80’s within days ash was raining down on the East Coast

Cinder Cone Volcanoes Are the smallest and most abundant Violent eruptions occur due to trapped gas- hot ash and lava are thrown from the vent Active for a short time and then become dormant

Where do volcanoes occur? Volcanoes are usually located where tectonic plates meet. This is true for the Pacific Ring of Fire, and around the Pacific Ocean where 75% of the volcanoes on Earth are found.

Volcanoes Around the World Ring of Fire

Convergent Plate Boundaries Most volcanoes occur at convergent plate boundaries As a plate sinks at a convergent boundary, it causes melting in the mantle and magma rises to the surface

Under Water Volcanoes can occur on land or under water Underwater volcanoes occur at divergent boundaries As plastes move apart, magma rises to fill in the gaps Iceland- is a volcanic island

Hot Spots Volcanoes occur at hot spots

Volcano Monitoring Volcano Observatories are set up on all active volcanoes that threaten the human population. These are designed to monitor and potentially to predict the eruptive behavior of the volcano in question.

Volcano Monitoring Seismicity Deformation Gas Output (on volcano and remote sensing techniques) These three things are the most important precursors to an eruption.

Seismic Activity Earthquake activity commonly precedes an eruption Result of magma pushing up towards the surface Increase volume of material in the volcano shatters the rock This causes earthquakes

Gas Monitoring Commonly gas output from a volcano increases or changes composition before an eruption. As magma rises to the surface it releases (exsolves) much of its gas content. This can be measured

Gas Monitoring Gas samples are collected from fumaroles and active vents. • Gas levels may also be monitored by remote sensing techniques

Openings where magma/ lava comes out A. Hot spot B. Cinder cone C. Vent D. Shied Volcano E. Composite Volcano

Made up of alternating layers of ash, explosive A. Hot spot B. Cinder cone C. Vent D. Shied Volcano E. Composite Volcano

Lave flows for a long way, gently sloping volcano A. Hot spot B. Cinder cone C. Vent D. Shied Volcano E. Composite Volcano

Smallest and most abundant, violent eruptions A. Hot spot B. Cinder cone C. Vent D. Shied Volcano E. Composite Volcano

Elaborate Volcano types worksheet Volcano cross section worksheet Poster- 3 types of Volcano- picture and description of each

Evaluate Plotting Earthquakes and Volcanoes Activity