Background

The damage caused by an erupting super volcano would be cataclysmic. The event of a super eruption of Yellowstone is a daunting reality to face for many Americans and for anyone located on earth. Yellowstone, more specifically the Yellowstone Caldera (a caldera is what is formed shortly after a volcanic eruption happens when all its magma is emptied), is approximately 30 miles by 45 miles and 5 miles deep (Pletcher, 2018), would send the world into a volcanic winter for upwards of 5 or more years (Rafferty, 2018), and can cool temperatures by 5 - 10 degrees Fahrenheit for a few years after the end of the volcanic winter (Rafferty, 2018). With all of these points being purely approximate, there is no hard evidence of what consequences of a super eruption at Yellowstone can prevail in the future.

This research report is designed to answer the question of ‘What is the Probability of Surviving a Super Eruption of Yellowstone Whilst Trapped in a House?’ This question will be answered using the help of the R Project for Statistical Computing, and QGIS; both of which are free and reproducible.

Scientists establish theories of what the ramification would be if a super eruption were to occur. Most can agree on what will happen, but theories differ about the time frame of the eruption’s aftermath. Many dispute on whether or not Yellowstone would cause extinction for humans on earth. When looking at the ramifications of a super eruption of Yellowstone, a couple of variables need to be accessed. Time, amount of ash, type of ash, blast zone, and weather patterns can all help lessen or worsen the disastrous event. Geologists are currently developing technology that can help predict when a volcano may erupt with greater accuracy each day. Hannah Shamloo, a graduate student at Arizona State University, and her colleagues had conducted research on fossilized ash deposits from Yellowstone’s last super eruptions (Hall, 2017).

Hannah and her team were able to identify trace crystals from the last super eruption of Yellowstone and determine the many variables that had to change before the eruption had occurred (Hall, 2017). Before Hannah’s research was done, it was suspected that the process of magma buildup beneath the volcano took over a century before a super eruption occurred. Hannah and the team were able to identify outer crystals of volcanic matter that showed a rapid shift in temperature, pressure, and water content before such an eruption took place. So rapid that the time frame shrunk to a couple of decades (Hall, 2017). Hall quotes “The time scale is the blink of an eye, geologically speaking” (Hall, 2017).

With such a finding being uncovered, one may now realize that such a daunting reality of a super eruption of Yellowstone can happen within a lifetime for a generation of humans.

Predicted Ramifications of a Super Eruption of Yellowstone

In the events of a super eruption of Yellowstone, here is the predicted outcome of such a tragic event:

  1. Underground activity beneath the Yellowstone Caldera causes an increase in magma and gases into the chamber years before the eruption takes place. With an increase of magma, the caldera starts to fill and starts moving the surface of the ground above it; similar to the events of Mt. St. Helen’s. This movement causes the water table to shift and allow moisture into the caldera, coming into contact with magma and accelerating the crystallization of magma along the edges of the caldera. This processes of water coming in contact allows for a shell to form and for pressure to increase.

  2. The ground above the caldera becomes too thin from years of stretching under the pressure of the caldera. Section by section, the weakest parts of the caldera shells are blasted into the air releasing years of pressure and magma; the eruption has started and wont end for another 24 to 48 hours. With a caldera that has the capacity of holding more than 6,700 mi^3 of magma, Yellowstone unleashes its contents over 50+ miles into the atmosphere. Volcanic ash clouds containing super heated glass that are between 752 and 1472 degrees Fahrenheit will fall over North American continent with a top speed of 125 mph (Lamb, 2008).

  3. Anyone in a radius of 1,000 km will die. Buildings and cars would be crushed under the weight of the ash. If breathed in the ash would suffocate and burn airways due to the heat of the ash. Any face respirators would melt in the heat of the ash within 1,000 km of Yellowstone. Breathing could be near impossible for anyone located in and around the United States.

  4. The suspended ash will cause all air traffic flights to be grounded for an extended amount of time. With the ash suspended more than 50 miles into the atmosphere, the ash would prevent the sun rays from reaching earth and the planet would fall into a volcanic winter for at least 5 years to lasting a decade.

  5. With the presence of a volcanic winter, growing crops in the United States, if not the whole planet, would be difficult. Violence would erupt over resources like food and water as they start to become scarce. With the United States being a major exporter in grain(s), soybeans, corn, beef, pork, and dairy, the risk of famine in the United States and in countries that import from the United States would be high. Martial law has been declared in the United States and in many other countries in an attempt to keep the situation under control. The United States would have to start importing food, reach out for humanitarian aid and a refugee crisis would occur in the wake of the eruption. Global economies that have major ties to the US dollar would decline and see that the purchasing power of US dollar crippled.

  6. With the volcanic winter still affecting the planet and growth of crops all around the planet, countries start to close their boarders for anyone traveling in or out. Valuable resources are no longer traded globally as countries struggle to feed their citizens. The global economy has stagnated as the policy of every man for themselves become the sure way to ensure survival of a civilization. Civilizations collapse one by one as violence ensues humanity.

Data

An image of the USGS prediction of Ashfall from a super eruption of Yellowstone (Figure 0.1) will be required for digitizing the image. The digitized image will then be exported to a shapefile which will be required for specifying which cities are in what ash zone. A data table of major cities in the United States acquired through R and the package tigris. A shapefile containing the location of Yellowstone caldera will be required for displaying in the final map (all of which will be included in the Methods section of this report). Figure 0.1 USGS Ashfall Boundaries of Yellowstone Super Volcano

Method

The main display option for the data will be presenting the findings with a map. A map of the United States with radius circles to display the amount of ash that will fall within each region; a map of a specified county/city and display what zone it’s in (ash amount, city name, probability of surviving). For the process of digitizing the USGS Ashfall Prediction of a Super Eruption of Yellowstone image, QGIS was used with the plugins “QuickMapServices” and “Vector Bender.” The QuickMapServices plugin was used to display a basemap in QGIS to be used as a guide in georeferencing the output shapefile. Vector Bender was used to help georeference the digitized USGS ashfall map to the basemap from the QuickMapServices plugin. In addition to the plugins and QGIS itself, the programming statistical language R project will need to be installed. The research grouped used RStudio to work with R. The process for digitizing the image involves:

  1. Import the USGS image into QGIS

  2. Creating a new GeoPackage Layer with a Polygon geometry type, appropriate names/location for the layer, and added fields/attributes of “Zone” assigned an integer type and “ThicknessRange” assigned an integer type and an attribute named “AshRange” assigned a text type. (Refer to Figure 1.0 “Creating New GeoPackage Layer”) Figure 1.0 Creating New GeoPackage Layer Figure 1.0 Creating New GeoPackage Layer

  3. Select the newly created GeoPackage in the layers pane and toggle editing. Using the newly available “Add Polygon Feature” button, trace over each zone using the mouse cursor and end each polygon by right-clicking the mouse. Ensure that proper capture of the zones are performed to avoid duplicates of data in further processing. When right clicking the mouse, this should prompt a window to pop up and for the data (Zone, ThicknessRange, AshRange) to be entered in. The attribute table should look similar to that of Figure 1.1 “AshZone Attribute Table.” Be sure to hit the “Save Edits” button.

Figure 1.1 AshZone Attribute Table

After all zones have been digitized, the file will now need to be exported to a shapefile. In the layers pane, right click the layer, click on “Esport,” and then “Save Features as…” Change the format of the file to an “ESRI Shapefile,” name your file and select a location for it. Leave all other settings as default and select ok.

Ensure that the plugin “Vector Bender” has been installed in QGIS. Vector Bender will allow for our shapefile to be georeferenced using the EPSG code of 4326. Open vector bender underneath the “Plugins” tab along with a basemap using the quick map services plugin. Select your shapefile of the ashzones of which you wish to bend, and to the right of “Pairs layer” select the first icon before the drop down button (outlined in blue in Figure 1.2), refer to Figure 1.2 Vector Bender Settings. The drop down menu should show “Vector Bender” in the menu. Ensure that the edit buttons outlined in red are selected; they will resemble a darker gray when it is chosen.

Figure 1.2 Vector Bender Settings

Back on the map, identify the digitized image on the map, import the .jpg image of the ashfall boundaries, and then turn on the basemap through the quick map services. Lower the transparency of the digitized image to show the key cities in the .jpg image. Select the “Vector Bender” layer in the layers pan and select the “add line feature” on the toolbar. Your setup should look similar to Figure 1.3 Vector Bender Mid-phase with the red outline being the “add line feature” tool.

Figure 1.3 Vector Bender Mid-Phase

Now that the cursor is a cross, left click Miami on the .jpg image, then zoom into the quick map service basemap and left click Miami. Finish by right clicking. An arrow should have appeared similar to Figure 1.4.

Figure 1.4 Vector Bendor Arrow

For the second arrow, select Seattle on the .jpg image, and then identify Seattle on the basemap. For greater accuracy, zoom into the basemap only enough to view the desired city as a point. Repeat the process above to add another arrow. For the third and final arrow, identify New York on the .jpg image and then repeat the process above. Your arrows should look similar to Figure 1.5.

Figure 1.5 Vector Bendor 3 Arrows

Now that the Vector Bender has points and arrows, select run. The shapefile is now georeferenced and should look similar to Figure 1.6. Be sure to save the edits made.

Figure 1.6 Georeferenced Shapefile

To acquire a shapefile of Yellowstone, searching the internet to find one may be too time consuming; making one may be faster. Look up the coordinates or location of Yellowstone on google maps to use as a reference. In QGIS with a basemap, use a similar process as above to create a new geopackage. Select polygon instead of multipolygon for the geometry type, and draw a polygon around the volcano. Export the volcano as a shapefile following the same process as above. Since the volcano was found using the basemap, there is no georeferencing that needs to take place.

After the ashfall and yellowstone shapefiles have been created and properly show up georeferenced on the basemap, open your R compiler. Loading in the package used for this project will look like this:

library(maps)
library(sf)
library(dplyr)
library(tigris)
library(tmap)
library(RColorBrewer)

If these packages are not installed on your machine, or if you’re unsure if they’re updated, the following code can be ran to install or update the packages at once:

install.packages(c('maps', 'sf', 'dplyr', ' tigris', 'tmap', 'RColorBrewer'))

To read in our shapefiles of the ash zones and Yellowstone, the following code will be used:

ashfall_shp <- read_sf('Q:\\StudentCoursework\\Haffnerm\\GEOG.435.001.2225\\DUCECR1126\\Project\\Attempt2OfDigitizingUS\\Attempt2ofGeorefferencedAshZones.shp')
yellowstone <- read_sf('Q:\\StudentCoursework\\Haffnerm\\GEOG.435.001.2225\\DUCECR1126\\Project\\Yellowstone\\YellowstoneSuperVolcanoLocatoin.shp')

The read_sf allows files that contain geometries to be read into R and placed into our variables ashfall_shp and yellowstone. To stick with consistency within our EPSG codes, the following lines of code will ensure that our variables are transformed to EPSG: 4326.

ashfall_shp <- st_transform(ashfall_shp, crs = 4326)
yellowstone <- st_transform(yellowstone, crs = 4326)

A dataset of major cities within the Untied States will need to be assigned a variable. This will later be used to define which city is in which ash zone,

cities_sf <- st_as_sf(us.cities, 
                      coords = c('long', 'lat'), 
                      crs = 4326)

With the cities now assinged a variables, a join will have to take place. The join which will be used will be st_intersection(). This will find all the cities that fall within, or intersects, an ashzone and assign the cities variable accordingly with the same fields that we created in Figure 1.1.

sf_use_s2(FALSE) ##included in case overlaps of the ashzones occured
cities <- st_intersection(cities_sf, ashfall_shp)
death_toll <- st_intersection(cities_sf, ashfall_shp) ##added to show a layer for deaths

Congrats! You now have geospatial data of major cities within the United States with an assigned value for which ash zone a city is in. To calculate the deaths in a city, we will be gauging which city experience roof collapes by using the information we know from the backgrounds section of this report. We found that 4 inches (roughly 100 mm) of ash was the amount of ash that puts a maximum load on roofs before catastrophic failure would result and the roof collapse, harming and deceasing the members of the household inside.

death_toll$dead_by_collapse_roof <- cities$MinThickne >= 100 ##creates a new column inside the variable death_toll and assigns a city either TRUE or FALSE if the city recieves more than 100 mm of ash

totl_death_sum <- death_toll %>% filter(dead_by_collapse_roof == TRUE) %>% pull(pop) %>% sum() ##sums up the total amount of the population if they have a TRUE value in their dead_by_collapse_roof column

modified_death_sum <- totl_death_sum*.90 ##accounts for 10% of the population not being in their homes and therefore not being crushed underneath their homes

The outputted number consist of the total deaths of everyone in the city in the event that all roofs had collapsed. To account for vacancy in homes and people trying to leave the city, the modified_death_sum variable accounts for 10% of the population not being in their homes and therefore not being crushed.

Now the results are ready to be displayed.

Results

For mapping the results of the data, tmap will be used to create an interactive map. With this, the map can be explored more thoroughly to better understand which ash zone each city falls into.Using the layer select tool on the left of the map will allow for the different layers to be toggled to view either the death toll or the cities of what range they’re in.

tmap_mode("view")
tm_basemap(leaflet::providers$Stamen.Toner) +
  tm_shape(death_toll,
           projection = 4326) +
  tm_bubbles(col = 'dead_by_collapse_roof') +
  tm_text('country.etc', size = .8) +
  tm_shape(cities) +
  tm_bubbles(col =('RangeOfAsh')) +
  tm_text('country.etc', size = .8) +
  tm_shape(yellowstone) +
  tm_bubbles() +
  tm_text('Feature', size = 1) +
  tm_layout(title = "Major US Cities affected by Ash fall from Yellowstone")

Map 1.0 Layer Map of the United States

For observing the predicted number of people that will succumb to their roofs collapsing, the value from the modified_death_sum will be displayed:

## [1] "Predicted Causalties:"
## [1] 4174457

The source of these lives that have been lost can be displayed by toggling off the “cities” layer in the interactive map and observing the cities labeled as “TRUE”. This number does not account for tourism in the aream, elderly and citizens with breathing problems or any other medical conditions that would make them more or less susceptible to the airborne ash. This number purely represent how many lives would be lost in the event that a homes roof had collapsed.

Conclusion

The damage caused by an erupting super volcano would be cataclysmic. When Yellowstone has a super eruptions, millions of humans will cease to exist in a matter of hours. Whether directly from the blast of the volcano, the ash fall suffocating them, being crushed by a collapsing roof, or a depletion of resources, there is little evidence to show that Yellowstone erupting will be pleasant for anyone on Earth. With an ash column reaching heights of 50+ miles into the air, ash clouds that reach above 700 degrees Fahrenheit, the effects of the eruption will certainly be felt around the world. According to Map 1.0, most cities within states immediately around the state of Wyoming will fall victim of their roofs collapsing. The estimated victims of roofs collapsing equates to more than 4 million people. Although this number does not include the amount of people to succumb to suffocation, burns, and the volcanic blast, it still gives a rough estimate of how deadly such an event can be. For people outside of the roof collapsing zone, these cities have a better chance of surviving the direct impact of Yellowstone. The indirect effects of Yellowstone may catch up to the population outside of the roof collapsing zone with the impacts of starvation, dehydration, and violence.

References

Hall, Shannon. “A Surprise from the Supervolcano under Yellowstone.” The New York Times, The New York Times, 10 Oct. 2017, https://www.nytimes.com/2017/10/10/science/yellowstone-volcano-eruption.html#:~:text=The%20early%20evidence%2C%20presented%20at,event%20took%20millenniums%20to%20occur.

Pletcher, Kenneth. “Yellowstone Caldera.” Encyclopædia Britannica, 16 Feb. 2018 Inc., https://www.britannica.com/place/Yellowstone-Caldera.

Rafferty, John P.. “volcanic winter”. Encyclopedia Britannica, 26 Nov. 2018, https://www.britannica.com/science/volcanic-winter. Accessed 16 February 2022.

Robert Lamb “How is volcanic ash made?” 23 September 2008. HowStuffWorks.com. https://science.howstuffworks.com/nature/natural-disasters/volcanic-ash.htm 17 May 2022