Tropical storm Hermine hit Texas hard yesterday. Severe flooding occurred in many areas and some tornados even touched down here in the North Texas area. When I was driving home yesterday, I saw some clouds and circulation that were indications of tornadic activity. Did you see any weather changes that hinted to you that tornados may be on the way?
Check out this video of flooding.
Check out this video of a tornado in Texas.
Have you heard the tropical storm Hermine is going to hit the coast of Mexico and Texas? The storm shouldn't pick up enough energy to become a hurricane (74 mph winds to become a hurricane). Southern Texas will be getting a lot of rain. Have you seen Dallas' weather forecast? We'll be getting some rain here too!
Check out this weather.com video
Think back to last year!!! Do you remember how a hurricane gains energy? What type of clouds bring thunderstorms?
Hydrothermal deep sea vents are places where amazing life forms exist. These lifeforms live deep under the sea where there is no sunlight! It's incredibly interesting to learn how life forms here exist and survive.
Click here to check out scientist Jeffrey Marlow's blog post about exploring deep sea vents.
In the next few weeks of class we will be asking ourselves--What is life? --What conditions do we need for life to exist?
Welcome to seventh grade science! This year we will be learning about life science, and with laboratory and scientific inquiry skills constantly in focus. I look forward to an exciting year!
It's tornado season! Tornadoes typically occur in Tornado Alley (Texas, Oklahoma, Kansas) during the spring and summer months. Warm humid air masses meet cold dry air masses, and sotrms form that often develop into tornadoes. Here is a video of a recent tornado that touched down in Oklahoma.
1. Winds occur because the earth is heated unequally. Warmer areas have low pressure and cooler areas have high pressure. Winds occur because air will always move from areas of high pressure (more dense)to low pressure (less dense).
2. We measure wind speed with an anemometer. We measure the direction the wind is coming from with an anemometer.
3. Local winds blow over short distances. Global winds blow over long distances.
4. Sea and land breeze occur due to unequal heating of the water and the land.
During the day, the land heats faster than the water. So, the high pressure cool air over the water blows to the land (low pressure) as a sea breeze.
At night, the land cools faster than the water. So, the high pressure cool air over he land blows to the water (low pressure) as a land breeze.
5. Global winds occur because the whole earth is not heated equally by the sun so pressure differences develop. Global winds curve due to the fact that the earth is rotation--this is called the Coriolis effect.
1. Temperature is the average energy of motion of a substance. Thermal energy is the total energy of motion of a substance. So even if a tea pot and a tea cup both have the same temperature, the larger amount of tea in the tea pot has a greater thermal energy.
2. Conduction does not heat the air well. Gases (air is a mixture of gases) do not conduct heat well.
3. The troposphere is heated when heat is transferred by radiation, conduction, and convection working together. First, heat is transferred from the sun to the earth by radiation. The ground absorbs this heat and then releases some of that heat by radiation and some by conduction. This heats only the air nearest to earth's surface. The convection currents occur when the heated air near earth's surface rises, and then cools and falls. The transfer of heat by convection is what heats most of the troposphere.
A magnitude 6.9 earthquake struck western China on April 14th. So far, the death toll is estimated to be about 600, and it is belived that 10,000 people may be injured. Many unstable buildings collapsed leaving people trapped under rubble. The area where the quake occurred is difficult to access, making rescue and aid more difficult.
Watch this video about the quake.
Check out this video of a volcano erupting in Iceland on March 31st. This volcano was dormant for 200 years before this eruption. Today, ariports in Northern Europe have been shut down because there is so much ash in the air due to the eruption. Do you remember why there is volcanic activity in Iceland?
1. We receive electromagnetic radiation from the sun.
- Infrared Radiation (IR) is not visible with our eyes and has a wavelength longer than that of visible light. It is felt as heat.
- Visible Light is visible as colors. Each color of light has a different wavelength (red is the longest and violet is the shortest).
- Ultraviolet Radiation (UV) is not visible with our eyes and has a wavelength shorter than visible light. UV radiation causes sunburn.
2. Not all sunlight makes it to earth's surface. About half of the energy from the sun is absorbed by the earth. The rest is reflected or absorbed by the atmosphere or reflected by the earth. See picture from class.
3. Scattering is when particles in the air reflect light in many directions. The short blue wavelengths of light are scattered at make the sky appear blue.
4. The greenhouse effect is when gases in the atmosphere form a blanket that traps heat around the earth. The greenhouse effect is a natural process and is needed to keep it warm enough on earth for organisms to live.
Understanding electromagnetic waves can be tricky. Remember that electromagnetic waves are a type of energy, and the energy we get from the sun is an example of these waves. Electromagnetic waves are also used when you use your cellphone, listen to the radio, and cook in a microwave. Visit this NASA website to learn more about different types of electromagnetic waves.
1. Soil is made up of rock particles (clay, silt, sand, and gravel), minerals, air, water, and organic matter (decayed organic material is called humus).
2. Loam is fertile, good for growing plants. The humus in loam provides nutrients and spaces for air and water--loam is about 25% air and 25% water. Also loam is about equal parts clay, sand, an silt, so the texture of the soil holds in a good amount of water. (Too much clay means too much water and too much sand means it doesn't hold in enough water.)
3. The soil horizons form in the order C, then A, then B. First bedrock is weathered to produce the C horizon (partially weathered rock). Then the C horizon is weathered and plants grow and contribute their parts to the soil which creates the A horizon (topsoil). Then particles from the A horizon (mostly clay and other rock particles) wash down and mix with the C horizon to make the B horizon (subsoil).
4. Humus is dark colored organic matter (made from plants and animals) that is found mostly in the topsoil. When remains of plants and animals decay due to activity of decomposes (like earthworms or bacteria) then humus is formed.r
5. Soil is mixed by organisms in the soil. Burrowing animals and earth worms can mix the soil.
1. Weathering breaks down rock into small particles, or sediment. Forces of erosion (water, wind, ice, or gravity) carry and move these pieces. The earth's surface is constantly changing because some rock is worn away, and then after erosion deposits the rock, new rock can be formed in a different location.
2. Mechanical weathering physically breaks rock into smaller pieces, but chemical weathering breaks rock down through chemical changes.
3 and4. SEE TABLES
5. Two aspects of the type of rock can change the rate of weathering: mineral composition and perm ability.
The mineral composition in important because only some minerals are soluble (able to dissolve) in water. If a rock contains minerals that are soluble in water, then it will weather more quickly.
Permeability is important because if a rock is permeable, water can seep into the rock. Water can then weather the rock more quickly because it can weather the inside of the rock too.
6. Climate can affect the rate of weathering. Weathering occurs more quickly in hotter climate than cold one (because chemical reactions happen faster at warmer temperatures. Weathering also occurs more quickly in wet climate (water is necessary for chemical weathering and for freezing and thawing to occur). The type of climate in which rock weathers the fastest is a hot and wet climate.
On February 27, 2010, and 8.8 magnitude earthquake shook Chile. The epicenter was off the coast of Maule, Chile, 115 km from the more populated city of Concepcion. This epicenter is not far from the epicenter of the 9.5 magnitude 1960 quake.
More info at USGS.gov
Video of Earthquake
Activity for 2/21-2/22:
At the summit activity continued at the Halema`uma`u crater. A large gas plume reached 600 meters into the air, and small amounts of ash were carried upwards also. In the crater lava activity continued with lava levels dropping and rising and lava circulating. Some small lava fountaining also occurred. 2 earthquakes occurred the were large enough to be located.
At the Pu`o`O`o crater some glow (of lava) was also visible. Lava flowed from the TEB vents onto the TEB flow field. Some vegetation was burned due to lava flows.
Respond by explaining what lava fountaining is AND copy and paste a link to a picture of lava fountaining into your reply.
Every day all Kilauea update info from http://volcanoes.usgs.gov/kilaueastatus.php
1. A shield volcano forms when quiet eruptions over time produce lava flows that run over land (and can spread out) and cool and harden into volcanic rock. Overtime, these layers of volcanic rock build on-top of each other to make a gently sloping shield volcano. (Example: Kilaeua)
2. Composite volcanoes form when repeated eruptions of pyroclastic flow (cooling volcanic rock particles of ash, cinder, and bombs) build up on each other. These are often steep, cone-shaped mountains. (Example: Paricutin)
3. Eruptions of lava flows (quiet) and pyroclastic flow (explosive) alternate to form composite volcanoes. The volcano is then built up of a layer of ash, cinders, and bombs and then a layer of lava over and over again. The volcanoes have a steeper slope at the top and then a gentler slope at the bottom. (Example: Mt. St. Helens)
4. Often the soils produced from volcanic eruptions and volcanic rock are actually high in nutrients and can be good to grow crops.
5. See above
Activity for 2/17-2/18:
At the summit:
The lava levels in the pit of Halema`uma`u crater were low, but the lava was still moving around inside the crater. At 7 AM a hybrid earthquake occurred alogn with rockfalls. At this time the lava level lowered more. Seismic tremors continued at steady levels and two earthquakes below Kilauea were large enough to be located.
The tiltmeter recorded DI deflation and a a "positive offset" at 7AM when the hybrid earthquake occurred. The GPS receivers also indicated contraction (they came closer together which confirms that deflation is occurring).
At the east rift zone:
The tiltmeter at Pu`o`O`o crater also recorded DI deflation. Pahoehoe lava flowed down the flow fields.
The Hawaiian volcano Observatory Page updates their info with images of tiltmeter and GPS recordings. Click here to see the recording. Post below by either explaining what the tiltmeter data shows occurred during the past few days in February OR explain what the GPS receiver show has occurred since March 2008.
Activity at Kilaeua 2/16-2/17:
At the summit, at Halem`uma`u crater there still lava spattering and movement in the crater. Another DI (deflation-inflation) event started at 9:30 PM yesterday. Episodic tremors were recorded throughout the night, starting at 6PM last night.
Also at the summit, there gas plume reaching 600 meters into the air. The plume is moving northward.
Click here to see a picture of a gas plume at the Haleuma`u crater, at the summit of Kilauea.
Currently, at the summit of Kilauea 900 tonnes per day of sulfur dioxide (SO2) gas is being released into the air. Between the years of 2003 and 2007 the average amount of sulfur dioxide released a day was only 140 tonnes per day.
In order to respond to this post click here and read about volcanic gases. Respond with a post that describes at least one effect of SULFUR DIOXIDE (SO2) GAS.
1. To see the different parts of a volcano see page 211 in your textbook.
2. High silica content means high viscosity magma. When there is high viscosity magma, it will not flow out of the volcano easily so explosive eruptions will be more likely.
3. A quiet eruption occurs when magma is low in silica content (low viscosity). Lava flows easily out of vents and volcanic gases bubble out of the lava. Pahoehoe and aa lava can be formed by quiet eruptions. Hazards from quiet eruptions are lava flows and fires.
4. Explosive eruptions occur when magma is high in silica content (high viscosity). Lava does not flow easily out of the volcano and gets clogged up in the volcanic vents. When the vents are clogged, pressure from the magma and volcanic gases builds up inside the volcano. When the volcano finally erupts it is an explosive eruption. This type of eruption will cause pyroclastic flow (rock particles of various sizes called ashes, cinders, and bombs). Ash fall, landslides, rock falls, and release of volcanic gases are hazards associated with explosive eruptions.
5. Changes at a volcano can signal to scientists that it may erupt. Scientists often use tools such as tiltmeter or GPS receivers to see if there is any movement or tilt of the ground at a volcano. Tilt and ground movement can indicate that a volcano may erupt soon. Earthquakes occurring at a volcano (often monitored by seismographs) can indicate that a volcano may erupt soon.
Also, volcanic gases escaping signal that a volcano may erupt soon.
Activity from 2/15-2/16:
At the summit, at Halem`uma`u crater there was even more lava spattering and movement in the crater. Inside the crater, the lava level repeatedly rose as fell, changing it height by as much as 10 meters. This movement occurred from 8 AM to 6 PM, then it rose and fell less, then by 3 AM much rising and falling was occurring again. Another DI (deflation-inflation) event started). At 12:20 PM yesterday deflation occurred, and afterwards at 7:00AM today inflation occurred. When more movement of the lava occurred more seismic tremors were recorded at the crater.
At the TEB vent, lava continued to flow out and feed surface lava flows.
Deflation-Inflation or DI events are know to occur at the summit of Kilauea (at Halema`um`u crater) when the crater is expanding or contracting. Click here to read a "Volcano Watch" article from May 2009 about the significance of DI events at Kilaeua. Respond to this post by commenting with something you have learned about DI events at Kilauea.
Activity for 2/9-2/10:
At the summit, at Halema`uma`u crater there was lava spattering in at least two places in the bottom of the crater. Rock falls also occurred in the crater last night. At 1:15 AM the view from the webcam was blocked by fumes and rock dust. At 4:10 AM a rock fall occurred. At 4:15 AM there was finally a clear view form the webcam again and lava has risen above the opening in the crater. Seismic tremors were variable moving between being constant and coming in episodic bursts.
Lava continued to flow out of the TEB vent. Surface lava flows are advancing slowly and both pahoehoe and aa flows have been detected.
Rock falls are not uncommon at Kilauea. Click here to see a video of lava movement within the Halema`uma`u crater and rock falls from September of 2009. Respond below by answering this question: what do you think is causing rock falls at the Halema`uma`u crater?
Everyday Kilauea update info is found at http://volcanoes.usgs.gov/kilaueastatus.php.
Activity for 2/7-2/8:
At the summit, at Halema`uma`u crater there was lava spattering in at least two places in the bottom of the crater, and the lava level was rising. The amount of sulfur dioxide gas leaving the vent is still elevated compared to the 2003-2007 average amount. GPS receivers recorded expansion at the Halema`uma`u crater. Seismic tremors increased at 9 PM last night and then decreased. There was a normal amount of smaller earthquakes that occurred. There were five earthquakes beneath Kilauea that were able to be located.
At the Pu`u`O`o crater there was an increase in seismic tremors, and the tremor level was constant at the TEB vents. GPS receivers recorded expansion of the rock at the Pu`u`O`o crater.The number of small earthquakes were within normal ranges. Scientists were able to map out a pahoehoe lava flow from the TEB vent, and they discovered that it had moved 700 meters in the last five days.
Kilauea is currently erupting, and is a very active volcano. Click here to read about the activity at nearby volcano Mauna Loa. After you have read about the current activity at Mauna Loa and about the current activity at Kilauea mentioned in this post, respond to this post by comparing and contrasting the current activity at these two volcanoes.
1. Viscosity is a physical property. Viscosity of a substance can be observed without changing the chemical composition of the substance.
2. As viscosity increases a liquid will flow more slowly. So a high viscosity means a slower flowing liquid. A low viscosity means a faster flowing liquid.
3. Increased friction between particles mean higher viscosity (more resistance to flowing). So increased friction also mean a liquid will flow more slowly.
4. Temperature and silica content effect the viscosity of magma.
Higher temperature means a lower viscosity.
Higher silica content means a higher viscosity. (think "silica is sticky")
Aa is higher viscosity magma, and pahoehoe is lower viscosity magma.
Activity from 2/6-2/7:
At the summit, at Halema`uma`u crater there was lava spattering in at least two places in the bottom of the crater, and the lava level was rising. Inflation of the summit that had been occurring was decreased. There were seven earthquakes beneath Kilauea that were able to be located.
At the Pu`u`O`o crater there also a decrease in inflation that had been occurring. Seismic activity at both the Pu`u`O`o vent and TEB vent was low.
Seismic activity and earthquakes are important to scientists when they are study volcanoes. You can click here to see a map of recent earthquakes on the island of Hawaii. Then, click here to read about monitoring seismic activity near volcanoes, and use the information from this website to respond to either one of the two prompts below.
- What happens in a volcano to trigger earthquakes?
- How do scientist measure seismic activity at volcanoes?
- Volcanoes typically occur at plate boundaries (although they can also occur at hot spots). The occur at plate boundaries because these are place in the crust where magma can come to the surface.
- At a divergent plate boundary the plates pull apart. In between the plates magma can come to the surface and create a volcano. Volcanoes can occur at both divergent boundaries on land and divergent boundaries in the ocean floor.
- At convergent plate boundaries where subduction is occuring volcanoes can exist. As one plate is subducted beneath the other some of the rock will melt into magma and create volcanoes. This can happen where two oceanic plates collide (this creates and island arc) or where one continental and one oceanic plate collide.
- At hotspot mantle material has melted and risen near the surface where it can easily erupt as magma and form a volcano.
- EXAMPLES
Convergent- Alaskan volcanoes, Indonesia (island arc), Phillipines
Diveregent- Seafloorspreading/mid-ocean ridges, volcaneos in the Great Rift Valley
Hot spot- Hawiian islands, Yellowstone
Activity for 2/3-2/4:
At the Summit:
At Halema`uma`u crater lava was visible through 3 openings in the bottom of the crater. The glow from the lava is more intense than it has been recently. Nine earthquakes were able to be located below Kilauea last night. Small background earthquakes also occurred, but only the larger earthquakes are able to be located. Pieces of ash were carried out of the crater by the gases leaving the vent.
TEB Vents: Lava continues to flow out of the TEB vents and down the flow field.
Click here and look at recent pictures of Kilauea. Specifically, be sure to look at the February 3rd pictures of aa lava. Then, search for on the internet or look in a book to read about characteristics of aa lava. Respond to this post by describing some characteristics of aa lava (what is aa lava like?).
Activity at Kilauea from 2/2-2/3.
Activity a both the summit and at Thanksgiving Eve Breakout vents continued. Lava flowed out to surface flows at the eastern rift zone. Still no lava is flowing through the ocean entry.
At the summit the GPS system detected and elevated number of seismic tremors. Many earthquakes occurred that were so small that their exact location could not be determined. There were 5 earthquakes that were large enough to be located below Kilauea.
Earthquakes often occur where there is eruption and movement at volcanoes. Click here to read more about volcanic earthquakes. After reading the linked page, comment by answering this question:
Why do you think that people live near to Kilauea if earthquakes are signaling an eruption? Think about how lava flows and the activity at Kilauea. There is no right or wrong answer, just be sure to explain yourself.
Activity for 2/1- 2/2 at Hawaiian volcano Kilauea.
Activity was occuring at two of Kilauea's vents; the summit vent and the TEB, or Thanksgiving Eve breakout vent.
At the summit, the summit vent is emmiting a sulfur dioxide containing gas plume. Also, at the Halema`um`ua crater the lava was seen falling and rising.
At the Pu'u'O'o crater gases (including sulfur dioxide) are also released. The magma is then traveling to the TEB vent and erupting.
Kilauea is a shield volcano, and the fact that it is a shield volcano explains the pattern of lava flows and eruption that we see there. Click here to learn more about shield volcanoes. Read carefully through this website, then below post a response that tells me something you have learned about shield volcanoes from reading the site.
GPS satellites can very precisely measure markers on earth's surface. These markers can be set up on opposite sides of the fault to detect BOTH vertical and horizontal movement at faults. So, GPS satellites can detect movement at reserve, normal, and strike skip faults.
Friction between rocks on either side of the fault causes them to stick together. This causes stress to build up. Eventually this stress causes the rock to move and break.
No, geologists cannot predict exactly when earthquake will occur. We can monitor movement at faults, but that does not mean that we can determine precisely when and where the earthquake will occur.
A seismograph is a device that measures seismic waves. For the seismograph to work a drum with paper rolls to release more paper, and a pen stays in place to record any movements in the ground on the paper. If the ground moves, the machine and paper move so that the pen makes lines up and down on the paper showing the time and amount of ground movement.
Be sure to be reviewing all material on faults and earthquakes. Use your 3-fold notes and study questions.
Also, make sure your earthquakes research is complete, and when it is you may begin working on the glogster project.
1. An earthquake is a shaking of the ground. Earthquakes occur when rock underground shifts or moves after stress increased (becasue of friciton). Stress will build up where there is a fault and then eventually this stress will cause an earthquake to occur. The rock will then break, at the focus, and trigger an earthquake. Earthquakes occur at faults, often near plate boundaries.
2.
- P-waves, or primary waves move in a straight forward motion. They compress and expand the ground.
- S-waves, or secondary waves moves side to side or up and down and shake the ground back and forth.
- Surface waves travel at the earth's surface and they travel more slowly than S or P waves. The can make the ground roll or shake and can often cause a lot of damage.
3. P-waves arrive first, then S-waves, then surface waves. A seismograph would detect them in this order.
4. The Richter and Moment Magnitude scales rate the size of an earthquake (and the amount of energy released). The Mercalli Scale rates the amount of damage in a specific area.
One single earthquake will only have one Moment-magnitude and Richter rating. However an earthquake can have more than one Mercalli rating. This is because in different cities the damage done by and earthquake may be different, meaning more than one Mercalli rating.
Also, the Moment-magnitude scales is better than the Richter scale at estimating the size of further away or larger earthquakes.
5. Each time an earthquake's magnitude increases by one point (example from a 4 to a 5), 32 times more energy was released.
Here's a useful link to see animations of reverse, normal, and strike slip faults.
CLICK HERE FOR LINK TO ANIMATIONS OF TYPES OF FAULTS
Review of Forces int he Earth's Crust questions form class today. The question are glued in your spiral.
1. The 3 types of stress that can act on rock are tension, compression and shearing.
- Tension pulls on rock, stretching it so it become thinner in the middle.
- Compressions squeezes rock inwards so that it folds.
- Shearing causes two pieces of rock to slip past each other, moving in different directions.
2. The three types of faults we discussed are strike-slip faults, normal faults, and reverse faults.
- At strike skip faults there is no hanging wall or footwall and the 2 pieces of rock slip past each other.
- At normal faults the hanging wall slides downwards relative to the footwall that slides downwards.
- At reverse faults the hanging wall moves upwards relative to the footwall that moves downwards.
3.
- Normal Fault: Tension is occurring (forces are pulling rock apart). This could occur at a divergent plate boundary.
- Reverse fault: Compression in occurring (forces push rock together). This could occur at a convergent plate boundary.
- Strike-slip fault: Shearing is occurring (force causes rocks to slip past each other). This could occur at a transform plate boundary.
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