Mr. Longoria's Earth Science

More than 3 million earthquakes occur each year, or about one earthquake every 10 seconds. Most of these are small and go unnoticed. Each year, however, a number of powerful earthquakes occur. Because such earthquakes are among the most destructive of natural disasters, it is important to understand how and where they occur in order to prevent the loss of lives and property. Most earthquakes result from the strain that builds up at plate boundaries or faults. This week, we will study the causes of earthquakes as well as how the energy released travels as waves through the earth. Homework #9 : Due Tuesday, April 7, 2009 Textbook: read pages 214-216, questions 1-5. Spring Break starts this Thursday, April 9, 2009. ENJOY!

One of the most dramatic activities with plate tectonics is the eruption of a volcano. Our objectives, in the coming days, are to analyze how magma forms as a result of plate motion and interaction. We will explain why plate boundaries are the sites of most volcanic activity. The photograph shows Mount Redoubt bellowing steam and ash across the Cook Inlet from Ninilchik, Alaska, Thursday, March 26, 2009. Ash from the volcano is seen on the snow. The volcano on the west side of Cook Inlet erupted Thursday morning sending ash clouds an estimated 65,000 feet (nearly 20 kms) into the air dusting the towns on the Kenai Peninsula including the towns of Kenai, Ninilchik and Homer. (AP Photo/Al Grillo)  Assignment: Web Quest Report - How and Where volcanoes Form: A Study of an Active Volcano Assignment due date: Monday April 20, 2009 This assignment requires the use of the internet. This is a term project that must be completed by the due date - no exceptions. Use the link: How and Whe...

Scientists classify boundaries between two lithospheric plates according to plate movement. There are three main types of plate boundaries: divergent, convergent, and transform. We will contrast the three different types of plate boundaries as well as describe and assess the causes of plate movement. En Español Las placas litosfèricas se mueven como unidades coherentes en relación con las otras placas. Las placas tienen tres tipos distintos de bordes, que se diferencian en función del tipo de movimiento que exhiben. Los tipos de bordes son: Divergente, Convergente y Transformante. Contrastaremos los tres diferentes tipos de limites de placas y tambien describeremos y evaluaremos las causas de movimiento de las placas. Homework # 7 : due Wednesday, March 25, 2009 Review Book : Chapter 3, read pages 67-72; do questions 38-45, 52-57, on pages 70-72.

Although we cannot directly see the interior of the Earth, scientists use instruments to collect data about it. These data are used to make a model of what the inside of the Earth is like. The Earth is made up of three main layers. At the center is a dense core . The core is subdivided into two sections: an inner layer composed of solid iron and nickel, surrounded by an outer layer of melted iron and nickle. Outside the core is the mantle . The mantle is made up of liquid and solid rock that moves and churns. the outermost layer of the Earth is the crust . Compared to the other layers, the crust is very thin and cold. The continents and oceans are part of the crust. The most abundant element inside the Earth is iron. This week we will focus on the movement of Earth's crust and the forces that make it happen. We will look at the theory of Plate Tectonics and the individuals that made the discoveries that developed the theory. Homework # 6 is due Monday, March 16, 2009 (Marki...

The ocean lithosphere suffers extensive hydrothermal alteration at the ridge, but the rocks eventually finish up subducting back into the mantle: It is because these fluids are released in the Benioff Zone as the slab is subducted that magmas are generated in the mantle wedge above the subduction zone. It is fluid, not friction, which is responsible for active margin magmatism. But it is ridge processes which make it all possible.