Monday December 5, 2016 Notebook, Pencil

The Focus and Epicenter of an Earthquake Focus - The point within (inside) Earth where faulting/breaking of rock begins or hypocenter Epicenter – The point directly above the focus (where rocks break and move) on the surface is the epicenter

Waves of energy released as vibrations caused by an earthquake Seismic Waves Waves of energy released as vibrations caused by an earthquake

Seismic Waves Primary Waves (P waves) Secondary Waves (S waves) Fastest (arrive first) Travel through liquids & solids Push and pull waves Secondary Waves (S waves) Arrive second Cannot travel through liquid

Seismic Waves Surface Waves Move along the Earth’s surface Not through the interior Make the ground roll up and down Largest movements Cause the most damage

Seismographs Seismograph – is an instrument that constantly records ground movements Separate seismographs record side-to-side movements and up-and–down movements When the ground moves in an earthquake, the heavy weight moves and the pen attached to the weight records the movements Turn to page 57 in your book

Tuesday December 6, 2016 Notebook, Pencil

Supplies for next week!! Liquid glue Baking soda Vinegar newspaper

Magnitude Richter Scale - Scale developed in California during the 1930’s by scientist Charles Richter and Beno Gutenberg Based on a scale of 0-10 8 or higher is considered extremely powerful Magnitude is based on how fast the ground moves at a seismic station Moment Magnitude Scale – based on the total amounts of energy released by earthquakes New more accurate scale used (used in our book to measure magnitude) For each scale, an increase of one whole number indicates an increase of 32 times as much energy than the previous number Example - magnitude 5 EQ releases 32 times more energy than a magnitude 4 EQ

Aftershock A smaller EQ that follows a more powerful EQ in the same area Other damage – broken pipes and fires can cause great damage after an EQ The moving of the ground usually does not injure people – they are injured/killed by building collapsing on them

Liquefaction Liquefaction – a process in which shaking of the ground causes soil to act like a liquid Soil becomes like a thick soup Occurs in areas where the ground is made up of loose sand and silt and contains large amounts of water

Tsunami Tsunami – a wave of water triggered by an earthquake, volcanic eruption or landslide Sometimes called tidal waves Can be several waves that arrive hours apart

Predicting Earthquakes Can only give long term predictions based on the EQ risk of an area Scientists monitor stress along faults Tilts or changes in the elevation of the ground Slow movements or stretching in rock The development of small cracks in the ground

Earthquake –Resistant Buildings Base-isolators – placed between a building and its foundation. They are flexible layers that are stacked Open space/moat – open space give the building room to shake Shear walls – add strength to the structure with steel supports Cross braces – X shaped braces help building keep its shape during shaking

Wednesday December 7, 2016 Wednesday December 7, 2016 Notebook, pencil

Volcanoes Wednesday December 7, 2016 Volcano – is an opening in the Earth’s crust through which molten rock, rock fragments, and hot gases erupt. Magma – molten rock under the Earth’s surface Lava – magma that has reached Earth’s surface Wednesday December 7, 2016 Notebook, Pencil

Volcano Structure

Pyroclastic Flow A dense cloud of superhot gases and rock fragments that races downhill. Ash – volcanic ash is made up of rock fragments less than 2 millimeters in diameter Cinders – cinders contain holes and tunnels left by escaping gas Block – large fragments are called blocks or bombs

Volcanoes Most volcanoes form along plate boundaries Where oceanic plates sinks beneath another plate – subduction zones Where plates are pulling apart, allowing magma to rise from the mantle Great Rift Valley in Africa Mid Atlantic Ridge Form over Hot Spots 80% are along the subduction zones of the Ring of Fire

Types of Volcanoes Shield Volcano – is shaped like a broad, flat dome Build up from many eruptions of lava that is relatively low in silica Flows easy and spreads out in thin layers

Types of Volcanoes Cinder Cone – Is a steep, cone-shaped hill formed by the eruption of cinders and other rock fragments that pile up around a single crater Cinders from gas rich magma erupts

Types of Volcanoes Composite Volcano – Is a cone shaped volcano build up of layers of lava and layers of rock fragments Its magma is high in silica making the magma thick Steep at the top and flattens at the bottom Have VERY violent eruptions Expanding gases trapped rising magma tend to cause explosions Hardened lava from earlier eruptions often plugs opening

Scientists Monitor Volcanoes To predict when future eruptions will occur Volcanoes can go 100’s of years between eruptions Monitor magma movement under ground Earthquakes Changes in the tilt of the ground Temperatures at openings, springs and lakes Amounts and types of gases given off Mount St. Helens

Thursday December 8, 2016 Notebook, Pencil

Friday December 9, 2016 Notebook, Pencil