Lava deltas are created when pahoehoe goes into the ocean and stays there for a long time. Lava deltas are fan shaped pieces of land that form in the ocean. When the lava flows into the ocean, it cools really quickly and breaks into pieces, which can be sand sized or block sized. The different pieces collect on a slope underwater and build the base of a structure that in time can hold up the lava flows that form the delta above the water. When the pieces of lava collect on a steep slope, then the side of the delta crumbles often and creates a bunch of submarine landslides.
The plates meet with each other, and if rough spots cause the movement to stop at the edges, the motion of the plates continue. When the rough spots can no longer hold, the sudden release of the built-up motion releases, and the sudden movement under the sea floor causes a submarine earthquake. This area of slippage both horizontally and vertically is called the epicenter, and has the highest magnitude, and causes the greatest damage. As with a continental earthquake the severity of the damage is not often caused by the earthquake at the rift zone, but rather by
Ricardo Perez Historical Processes of Puerto Rico San Fermin Earthquake of 1918 The geological position of Puerto Rico raises a concern for earthquakes in the modern day. The island is located very close to the junction of the Caribbean and North American tectonic plates. A combination of seismic and volcanic activity created the Caribbean islands as we know them today. All of the Caribbean islands, with the exception of Barbados, were created from the fierce volcanic activity of the millions of years ago during the Antillean Revolution. Violent movements of the plates in the Post-Glacial era created the Puerto Rican Trench, nearly 24,000 feet deep, which is the deepest point in the Atlantic Ocean.
The strength, distance, and length of the wind gusts determine how big the ripples become. The crest of a wave is its highest point. Wavelength is the horizontal distance, and wave height is the wave’s vertical distance. The last type of motion is currents. Currents are the ocean’s constant flow of water that is pushed on by either the wind or from tides that are caused by the moon’s gravitational field.
Examples of regional metamorphic rocks include schist and gneiss. Thermal metamorphic rocks, also known as contact metamorphic rocks, are formed by extreme heat along with quite a bit of pressure. The pressure pushes the molten rock against the Earth's surface, causing it to recrystallize. Examples of thermal metamorphic rocks are marble and sandstone
The force of one plate being dragged under another causes intense friction and the pressure increases. Eventually, there is so much pressure that the plates suddenly jolt, causing an earthquake. Where an oceanic plate meets a continental plate, sediments are thrust upwards. Due to the friction caused by the plates scraping against each other, the temperature in the mantle increases. Magma rises forming a long chain of volcanic fold mountains for example the Andes.
The earthquake began off of the north-eastern coast of Honshu and caused catastrophic damage. The coastal areas were hammered by a “series of large tsunami waves that devastated many coastal areas of the country, most notably in the Tōhoku region (northeastern Honshu)”. (“Japan Earthquake and Tsunami of 2011”, 1) According to Encyclopedia Britannica… The epicentre was located some 80 miles (130 km) east of the city of Sendai, Miyagi prefecture, and the focus occurred at a depth of 18.6 miles (about 30 km) below the floor of the western Pacific Ocean. The earthquake was caused by the rupture of a stretch of the subduction zone associated with the Japan Trench, which separates the Eurasian Plate from the subducting Pacific Plate. (Some geologists argue that this portion of the Eurasian Plate is actually a fragment of the North American Plate called the Okhotsk microplate.)
The earthquake occurred in the backarc region of the convergent boundary where the Pacific Plate subducted beneath the Eurasian Plate. The earthquake shaking caused moderately severe damage, VIII on the Mercalli scale. The jolting movement of the seabed made the water rise and fall, which set off a terrifying tsunami. The fast-moving waves spread in all directions. They hit Okushiri less than four minutes later.
J. Subbiondo © 2004The CrustThe outer layer of the Earth is called the crust. It is made up of rock that floated to the surface when the Earth was formed. It is not a continuous layer, but is made up of large masses called tectonic plates.These plates drift slowly across the Earth's surface (tectonic means moving).The movement of these plates creates mountains and valleys.At weak points in the crust, it causes volcanic eruptions. And when plates bump into each other, earthquakes occur -- emitting shock waves or vibrations called seismic waves. The crust is the Earth's coldest layer.
The continental crust floats much more freely on the magma. Movements deep within the Earth, which carry heat from the hot interior to the cooler surface, cause the plates to move very slowly on the surface, about 1 to 10 cm per year. Tectonic plates move because mantle rocks near the radioactive core are heated and the warmer rocks rise while the cooler