By: Julia Dickerson Lassen Volcanic became a national park on August 9, 1916 because of its significance as an active volcanic landscape. Lassen Peak started erupting in 1914 and had the best activity until 1920. The four types of volcanoes in the world are found in Lassen Volcanic’s 106,000 acres. Lassen Volcanic National Park was formed by plate tectonics. The theory of plate tectonics says the expanding oceanic crust is thrust beneath the continental plate margins. It penetrates deep into the Earth to be partly remelted. The result is magma (molten rock). These became the feeding chambers for volcanoes in Lassen Volcanic National Park. Volcanic rocks can be found in Lassen Volcanic National Park. They are igneous rocks with volcanic origin. Igneous rocks are formed by molten rock that cools and becomes solid. There are three main types of igneous rocks; Intrusive, Extrusive, and Hypabyssal. Intrusive igneous rocks are made from magma that cools and solidifies within the crust of the planet. Extrusive igneous rocks are made at the crust’s surface as a result of partial melting rocks within the crust and the mantle. Hypabyssal igneous rocks are made at a depth in between volcanic and plutonic rocks. The special landforms in my National Park are volcanoes. The four types of volcanoes in the world can all be found in Lassen Volcanic’s 106,000 acres of land. There are cinder cone volcanoes, composite volcanoes, shield volcanoes, and lava dome volcanoes. A cinder cone volcano is the most simple type of volcano. They are blobs and particles of congealed lava that is ejected from a single vent. When the lava is blown into the air it breaks into little pieces that solidify and fall as cinders around the vent to form an oval or circular cone. A composite volcano are mostly steep-sided, symmetrical cones of large dimension made of bombs, blocks, cinders, volcanic ash, and lava flows. They could rise up as much as 8,000 feet above their base. A shield volcano is almost entirely built by fluid lava flows. Lava dome volcanoes are formed by small, bulbous masses of lava that are too flow at a great distance. A Lava Dome grows large by expansion from the inside. You can find boiling mud pots and hissing fumaroles that are still changing and shaping the land in Lassen’s mountain forests. In the hydrothermal areas at Lassen Volcanic there are roaring fumaroles, boiling mud pots, sulfurous gases, and steaming ground that are all linked to active volcanism. They are all reminders of the ongoing eruptions in Lassen Volcanic. Weather is also very important in Lassen Volcanic National Park. Winter shapes the land a lot; snow begins to accumulate in October, but it doesn’t melt in some places until July. Weather in summer is more predictable with the warm, dry days, cool nights, and blue skies. Lassen Volcanic was in the process of making an Environmental Assessment for a Weed Management Plan. The increase in dominance and distribution of weeds has began competing with native species and the disruption of ecological systems. Lassen Volcanic is making a plan to help guide future management of the weeds. Lassen Volcanic needs to put more vegetation and trees into the park to help stabilize the flanks. Officials say that they need to install turnouts along the trail for people’s safety. Plus, they’re going to have a new trail connecting to the Manzanita Creek Trail to the Lassen Peak Trail. One more thing that they’re going to do is add a trailside toilet for people to use. Putting these things in the park will make it safer, more fun, and more people will want to come and check out the volcanoes. Topographic Map State Map Country Map Websites: Lassen Volcanic National Park Information Page. John William Uhler, 1995- 2007. Web. 18 May 2010. <http://www.lassen.volcanic.nationalpark.com/info.htm>. Nps.gov. Web. 18 May 2010. <http://www.nps.gov/lavo/index.htm>. USGS. John Watson, 6 Feb. 1997. Web. 7 May 2010. <http://pubs.usgs.gov/gip/volc/types.html>. Nps.gov. Web. 5 May 2010. <http://search.usa.gov/search?affiliate=nps&v%3Aproject=firstgov&query= Lassen+Volcanic&x=7&y=5>. National Parks Traveler. Trailhead Interactive, 2010. Web. 10 May 2010. <http://www.nationalparkstraveler.com/2009/12/officials-lassen-volcanicnational-park-proposing-work-lassen-peak-trail5147>. Book: Vogel, Carole G., Michael Wyession, Ph.D., Michael J. Padilla, Ph.D., Ioannis Miaoulis, Ph.D., and Martha Cyr, Ph.D. Prentice Hall Science Explorer. Upper Saddle River, NJ: Pearson Prentice Hall, 2005. Print. Inside Earth. Newspaper: Explorer. Upper Saddle River, NJ: Pearson Prentice Hall, 2005. Print. Inside Earth.