Physical Geography Processes and Patterns

On June 21st, Seattle experiences the longest daylight of the year (from 5 am to 9 pm) and quite a short nighttime (from 12 am to 2 am). This is due to the fact that during this time, the sun’s zenith is the furthest away from the equator and reaches the northern part of the world, so that the northern hemisphere is tilted towards the sun at 23.5 degree angles. This creates summer for the northern hemisphere, so Seattle (which is located at the Pacific Northwest) experience longer daylights. Vice versa, On December 21st, Seattle experience shorter daylight and longer nightlight. This happens because of the December Solstice, when the sun zenith reaches the southern part of the world, so the southern hemisphere is tilted towards the sun at 23.5 degree angles. As a result, Seattle experience very short daylight (from 8 am to 4 pm) and longer nighttime. In contrast, Quito experience pretty stable daylight throughout the year (from 6 am to 6 pm). This is because Quito, Ecuador is located right at the equator. Countries that are located on the equator experience 12 hours of daylight all year long. During solstices, the sun is tilted towards the northern or southern hemisphere, so those areas respectively experience longer daylight. However, since the equator is located halfway between the hemisphere, it doesn’t really matter where the sun is tilted towards, countries in the equator are still going to experience 12 hours of daylight.

Intrusive igneous rocks became a sedimentary and metamorphic rock through a process called the rock cycle. The process usually begins with a molten magma or lava that erupts from the volcanoes. When the magma cools down and solidifies, it became an igneous rock. Intrusive igneous rocks are igneous rocks that cool down slowly beneath the earth’s surface, as opposed to extrusive igneous rocks that cool quickly above the surface. After that, igneous rocks are then broken down into small pieces by a process called weathering and became sediments. The accumulated sediments then became compacted over time (called lithification) and they started to form sedimentary rocks. When sedimentary rocks are subjected to an extreme increase in pressure and temperature (heat), they started to transform into metamorphic rocks.

Millions of years ago, the Appalachian Mountains were a part of the Pangea supercontinent. It is located along the east coast of North America and north of Africa. The mountain range is originally formed from a convergent boundary between the North American Plate and African Plate. When these two continental plates collide against each other, both continents are crumbling upwards, resulting in the creation of the Appalachian mountain range. In terms of hazards possibility, the earthquake and volcanoes reference map shows that the Appalachian Mountains are quite prone to earthquakes but not volcanoes. From the lecture, we know this is because of the continental-continental convergent boundaries that push the two continents upward instead of subducts under one another, so it creates mountains with no volcanoes. However, as time goes by, the North American and African continents started to drift apart from each other. This is due to the continental drift and seafloor spreading, which is part of the Theory of Plate Tectonics. Theory of Plate Tectonics is a theory that the earth’s outermost crust (lithosphere) is divided into several plates, and these plates move relative to each other. In this case, the North American Plate and the African Plate are drifting away from each other, hence, the evidence of continental drift. According to the seafloor age map, the area around the Appalachian mountains are indicated in a dark blue color, which means that the seafloor age is quite young. This suggests that there is indeed a seafloor spreading that form a new area of oceanic crust.

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