CFrench - PHY103 Final

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Apr 3, 2024

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Preliminary Report of Environmental Findings Southern New Hampshire University PHY-103 Christian French March 3 2024 Dr. Folts

Executive Summary This summary is a report on the findings for the proposed Waterville subdivision development site. This report includes the overview of soil makeup, historical data, tectonics properties, weather analysis, and stream development for the area. Earthquakes, weather, and volcanic eruption proposes the most significant risk for this area. The first immediate threat for this development site is its proximity to Mt. Jefferson; it has an eruption around every 613 years, and by record, it has been 631 years since its last eruption, meaning it is overdue for one and it could happen at any given moment. Furthermore, the next immediate threat for the area is its proximity to a fault line. The fault line runs right beside all three sites, and causes frequent earthquakes, with an earthquake greater than a magnitude 6.5 happening around 95 years; it has been 85 since the last, meaning an extreme earthquake will happen within the next ten years or so. Stream development poses a great risk to site C. Site C rests on an incline that is right above a stream. This stream has the potential to erode the bottom layer of soil on this incline and create an overhand of this slope, raising the risk of a landslide. Stream development and landscape also pose a threat to sites A and B as well. Sites A and b reside on a floodplain next to Mackenzie River and its deltas. During high precipitation events, that occur every 5-10 years, the area runs the risk of flooding as it is a flat area that resides at the bottom of a mountainside, leaving the only place for precipitation runoff to land is within these two parts of the devolvement site. Basic Geology

Rocks are classified into three types: sedimentary, igneous, and metamorphic. Sedimentary rocks account for 75% of Earth's surface because that is where most sediment accumulates (Lutgens & Tarbuck, 2021). Sedimentary rocks form when sediment becomes compacted and/or cemented. There are three types of sedimentary rocks: classic, chemical, and organic. Classic is composed of other rocks that have been compacted into layers, such as sandstone. Organic rocks are made from biogenic matter, such as coal, while chemical rocks are made from dissolved minerals, such as silica, which aids in the formation of limestone. Next is igneous rocks, which are formed when magma cools. Igneous rocks can be found buried deep within the Earth's crust (intrusive) or on the surface (extrusive). Lastly, metamorphic rocks are formed from parent rocks. When these parent rocks reach high enough temperatures and pressures, they melt and change until they find equilibrium with their new environment. These are typically near the mantle. Metamorphic rocks are classified into two types: foliated and non-foliated. Foliated rocks have layers, such as slate, whereas non-foliated rocks do not (Helmenstine, 2023). On a scale of 1 being the oldest and 9 being the youngest, the sequence is as follows: 1. Layer H 2. Layer G 3. Layer F 4. Layer E 5. Layer D 6. Layer C 7. Layer B 8. Layer I 9. Layer A The conclusion I came to comes down to the order of the layers. The oldest rocks are always situated on the bottom layer, and newer, younger layers will form on top of it over time. Layer I is the second youngest, as it is cross-cutting. Cross-cutting in rocks states that one must exist before it can be cut, meaning the cut and the vent was formed after all the layers up to B were

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formed. A is the youngest and it is the one that has been left untouched by the vent and it is not present on the other side of the fault line. Within the stratigraphic, there is evidence of a fault line as layers H-B are displaced on one half and lie further up than the other half of the same layers The one that lays further up is often referred to as a hanging wall block, and the layer that is presumably left undisturbed would be considered a footwall block. This could have happened from an earthquake that applied pressure and stress to the layers and caused them to break into the respectful hanging wall and footwall block. Sedimentary layers can contain all three subtypes. For example, coquina is made mostly of "loosely cemented shells and shell fragments," whereas limestone is made of the mineral calcite, which is found near bodies of water (Lutgens & Tarbuck, 2021). These are most commonly found near or in the ocean, as well as in deltas or riverbanks. Coal is formed when ancient biogenic swamp organisms are compressed. Micas are an excellent example of how heat affects rocks. Metamorphic micas are strongly deformed, and the chemicals from the parent rocks cannot mix, resulting in stark contrasts between dark and light layers from the original parent rocks. With igneous rocks, granite is formed from a multitude of silica-rich magma slowly solidifying at a depth (Lutgens & Tarbuck, 2021) . Regarding the soil profiles, picture "A" shows an organic "O" layer and a topsoil "A" level that helps prevent erosion and weathering. However, picture "B" shows that the "O" layer has significantly decreased and has left the "A" layer slightly more vulnerable to erosion. The topsoil layer is gone in Picture "C," leaving only a very thin layer of organic material. You can see that the "C" bedrock layer is getting closer to the top as you look through these photos. These images show in order what is possible—and has probably happened—with certain areas of the

topographic map. There is a drainage layer on these mountains that descends to rivers and lakes, enabling water to move from the summit of the mountain into these bodies of water. Additionally, the altitude permits strong winds to strike certain areas of the mountain. When combined, these factors can gradually rub away organic and topsoil layers, sculpting the terrain into tiny valleys created by water continuously flowing in one direction. The underlying geology might impact an overlying neighborhood would lose its vegetation and have a large number of streams, both above surface and groundwater streams and bodies of water. Both of these would lead to an increase of erosion and the higher amount of water would lead to flooding. On top of this, limestone, as mentioned before, forms near bodies of water, which means it is also highly water soluble, making the land structure around these houses brittle and prone to cave-ins or cracks due to the pressure added on them on top of the running streams. Streams The landscape features present on the topographic map that directly resulted from stream processes are channels, valleys, floodplains, and oxbow lakes. The valley is described as the V- shaped lines on the far-right of the Waterville topographic map and on the left side of the same map. These are shown by the V-shaped and u-shaped lines on the map that point to higher elevation, showcasing the drainage being in the opposite direction. These valleys were formed from younger streams with a higher velocity and faster flow, causing this higher velocity to eat away at the rock and create this deep valley that is present over the course of many years. Meandering channels are also found in the middle of the map, located close to a reservoir, creating a floodplain. The floodplain is caused from a weaker flow and weaker water velocity.

The oxbow lake is formed when a meandering channel cut itself off, leaving a stretch of the river on its own. The erosion of a floodplain occurs when soil is worn away due to the flow of a floodway. Rivers flow through these floodplains, which results in a wide and shallow river. Floodplains are also formed naturally through the process of erosion and aggregation from river valleys. Considering it is a meandering channel, the valley floor will be comprised mainly of silt and clay (Lutgens et al., 2021) . When the floodplains flood, this sediment deposit causes lower water velocity, creating a bigger deposit of sediment to build up. This eventually leads to a levee being built, or a natural slope of sediment along the river's walls. Due to this sediment flow and dispersion, plot A would be the most at risk for flooding during development. This is due widely in part to side A being near the McKensie River and its deltas. Along with this, the site is located below a hillside that could be prone to erosion and a landslide because of the water pathway as water forms a path between site A and the hillside and right along the hillside, putting that corner where they meet at risk. Tectonics In the topographical map, there is a fault line that runs beside all three sites. The history of the area shows that there has been little to no hard activity with the fault line. There has also not been any significant change to the landscape around the fault line, leading one to believe that it is a transform boundary. Upon further investigation, this fault line is a part of the Cascadia Subduction Zone, connected to the Cascadia Volcano Arc where Mount Jefferson lies. Being a part of the subduction zone means the fault is a dip-slip fault, where one half of the fault "grows" over the

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other land mass. Using the Historical data, there has not been a volcanic eruption in over 600 years, but two of the largest fault activities have happened in the last 170 years. The highest magnitude happened 170 years ago with a magnitude of 7.3 on the Richter scale, and the fourth largest one happened 85 years ago with a magnitude of 6.9. Mount Jefferson is also thought to be extinct, but other volcanic eruption and fault activity has others believing that Jefferson might actually be overdue. The tectonics features leave the proposed development at risk to both landslides and earthquakes. The fault line runs through all three proposed sites, and even though there has not been any activity in 85 years, it happens around every 95 years, meaning either during development or shortly after development is completed, the area will be ravaged by an earthquake. Furthermore, the earthquake could contribute to a landslide near site A and site C, leaving both of these areas vulnerable. Site C rests on a hillside, meaning the landslide will destroy most, if not all, of the site, and Site A lies in an area where the flooding can be devastating when a landslide blocks the river's natural path. Weather For the proposed site, the average year-round temperature is a high of 85 degrees Fahrenheit and a low of 14 degrees Fahrenheit, with an overall average of about 51 degrees Fahrenheit according to the climograph. There was an average of close to 5.6 inches of precipitation, although that varies greatly from a majority of the maximum precipitations recorded. The maximum precipitations fell in line with temperature minimums, showcasing the winter is one of the harshest seasons they have. There was an average temperature of 31 degrees Fahrenheit in December, January, and February, with an average precipitation being 8.7 inches.

January held the highest precipitation event on the historical table. Once it crosses over into spring and summer, you can see the temperatures rise and the precipitation begin to fall, until it reaches autumn, and the temperatures begin to fall once again while precipitation begins to increase once again. The polar front theory is the theory that there is a boundary between the polar air masses and the tropical air masses, cold wind and warm wind respectively (Lutgens, et al., 2021). It is what makes the trade winds and westerlies, and this interaction is what creates the polar front. When these winds meet, mid-latitude cyclones develop, which can produce a multitude of storms varied solely by their location and season. Based on the climograph with a latitude of 47 degrees North and a longitude of 122 degrees West, it is the mid-latitude range, which can be impacted by polar font storms. Based on the information in the climograph and my knowledge of the atmosphere, multiple storms can form in this area. Most commonly, cyclones are formed in warmer weather and off of a coast. Mt. Jefferson is located around 130 miles off the coast, and cyclones travel up to 200 miles inland in their strongest front before they begin to lose power. This means that Mt. Jefferson is at risk of being hit by the cyclones that happen during the summer and warmer weather. These cyclones could be in the form of thunderstorms which would produce different forms of precipitation, such as hail and rain. When it comes to the winter, Oregon gets a lot of cold fronts so snow would be the most likely cause of precipitation with rain mixed in. According to historical weather data, the maximum precipitation event occurred in January 1953 with a total of 19.84 inches. The most likely cause for this would be a slow-moving thunderstorm. Slow-moving thunderstorms produce flash flooding, which can cause heavy amounts of rainfall. Due to the thunderstorm being slow-moving, it repeatedly moves over the

same area, allowing the rainfall to accumulate to a higher amount, such as 19.84 inches. According to a report made by the United States Geological Survey, there was a frontal thunderstorm that stayed within the area from January 15th until January 20th, with the precipitation happening from the 16th to the 20th, reaching its peak on the 17th and 18th (Rantz, 1953) . The recurrence interval is an equation to solve the average number of years that occurs between events/ In this case, it is extreme precipitation. The formula for this is: Recurrence interval = (n+1)/m Where n is the number of years on the record and m is the rank of the event. With this, we can calculate the recurrence interval for extreme precipitation events at the site, as follows: Recurrence interval = (74+1)/1 = 75 years With this, it shows that an extreme precipitation event of this level is expected to occur every 75 years. Seasonal and extreme precipitation can have a considerable impact on the surrounding landscape and stream discharge. There have not been a lot of high precipitation events recorded in the historical data table, so the development site would not be washed away by that alone. However, the site does lay within a floodplain, meaning that at any change with one instance of high precipitation, the water could overspill from the drainage basins and flood the proposed development site. On top of this, even though part of the development site (site C) lies at higher elevations, precipitation can lead to mudslides and band erosion that will essentially wash away the project site. Analysis

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Due to the safety and environmental hazards that are present within the project site, there is concern that lays there. Although there hasn’t been a volcanic eruption in a while, Mt. Jefferson is overdue for one, which raises concern. Tectonic activity is still present within the area, along with the proposed sites sitting near the fault line. Due to the tectonic activity and the proximity to the fault line, the initial construction of the subdivision will be a safety hazard as you run the risk of the building to collapse when they are under development, especially since a major earthquake happens close to every 95 years. Furthermore, due to a large part of the area being on a floodplain and part of it being on a slope, you run of the risk of floods during high precipitation events, which happen every 5-10 years. This flood would mainly impact areas A and B. The slope that part of the site lies on also runs the risk of collapse during the event of a landslide, something that can happen due to the river erosion on the bottom of the slope due to the stream, and high precipitation events weakening the slope. This problems effects site C. The risk that lies with this development site is not worth the development. There is a hazard for earthquakes, floods, landslides, and ashfall, which outweighs any potential profit that can be made. Precipitation, erosion, and tectonic hazards have the potential to offset the potential financial gain and run the risk of loss of life.

Sources Cited British Geological Survey 1998 - 2019. (n.d.). What is the difference between magnitude and intensity? British Geological Survey. Retrieved February 11, 2024, from https://www.earthquakes.bgs.ac.uk/education/faqs/faq17.html#:~:text=Magnitude%20is %20a%20measure%20of,distance%20from%20the%20earthquake%20epicentre. Do volcanoes occur in the ocean? (n.d.). https://oceanservice.noaa.gov/facts/volcanoes.html#:~:text=Sixty%20percent%20of %20all%20active,areas%20called%20%E2%80%9Chot%20spots.%E2%80%9D Homefacts.com. (n.d.). FARMINGTON, MO Earthquakes | HomeFacts . https://www.homefacts.com/earthquakes/Missouri/St.-Francois-County/Farmington.html How many active volcanoes are there on Earth? | U.S. Geological Survey . (2019, April 5). https://www.usgs.gov/faqs/how-many-active-volcanoes-are-there-earth Largest earthquake in Alaska . (n.d.). https://earthquake.usgs.gov/earthquakes/events/alaska1964/largest_in_alaska.php#:~:text =On%20March%2027%2C%201964%20at,to%20%24311%20million%20in%201964). Lay, T., Ye, L., Kanamori, H., Yamazaki, Y., Cheung, K. F., Kwong, K. B., & Koper, K. D. (2013). The October 28, 2012 Mw 7.8 Haida Gwaii underthrusting earthquake and tsunami: Slip partitioning along the Queen Charlotte Fault transpressional plate boundary. Earth and Planetary Science Letters , 375 , 57–70. https://doi.org/10.1016/j.epsl.2013.05.005 Lutgens, F. K., Tarbuck, E. J., & Tasa, D. G. (2021). Foundations of Earth Science (9th ed.). Pearson Education (US). https://mbsdirect.vitalsource.com/books/9780135851609

Maine Emergency Management Agency. (2020). Earthquake Facts . Maine.gov. Retrieved February 11, 2024, from https://www.maine.gov/mema/hazards/natural-hazards/earthquake/facts#:~:text=Ground %20vibrations%20during%20an%20earthquake,caused%20by%20the%20ground %20shaking. Plate tectonics and the Ring of Fire . (n.d.). National Geographic. Retrieved February 11, 2024, from https://education.nationalgeographic.org/resource/plate-tectonics-ring-fire/ Questions about Yellowstone volcanic history | U.S. Geological Survey . (n.d.). Rantz, S. E. (1953). Floods of January 1953 in Western Oregon and Northwestern California. Geological Survey Water-Supply , 1320-D . https://pubs.usgs.gov/wsp/1320d/report.pdf Ritchie, H. (2024, January 9). Natural disasters . Our World in Data. https://ourworldindata.org/natural-disasters#:~:text=In%20most%20years%2C%20the %20death,tens%20to%20hundreds%20of%20thousands. What is a fault and what are the different types? (n.d.). USGS.gov. Retrieved February 11, 2024, from https://www.usgs.gov/faqs/what-a-fault-and-what-are-different-types When did Lassen Peak last erupt? | U.S. Geological Survey . (2019, February 25). https://www.usgs.gov/faqs/when-did-lassen-peak-last-erupt#:~:text=The%20most %20recent%20eruptive%20activity,occurred%20during%20the%20following%20year. Where do earthquakes occur? (2012, December 13). United States Geological Survey. Retrieved February 11, 2024, from https://www.usgs.gov/faqs/where-do-earthquakes- occur#:~:text=The%20world's%20greatest%20earthquake%20belt,our%20planet's %20largest%20earthquakes%20occur.

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Which U.S. State has the Most Earthquakes? (n.d.). California Residential Mitigation Program. Retrieved February 11, 2024, from https://www.californiaresidentialmitigationprogram.com/Resources/Blog/which-state- has-the-most-earthquakes-in-the-us#:~:text=Not%20only%20is%20Alaska%20the,to %20ever%20strike%20the%20U.S%20. Witter, R., Briggs, R., Dura, T., Engelhart, S., Nelson, A., Witter, R., Briggs, R., Dura, T., Engelhart, S., & Nelson, A. (2022, September 26). Seismic sources in the Aleutian cradle of tsunamis . Eos. https://eos.org/features/seismic-sources-in-the-aleutian-cradle-of- tsunamis World Health Organization: WHO. (2019, November 8). Earthquakes . https://www.who.int/health-topics/earthquakes#tab=tab_1

CFrench - PHY103 Final

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