Fina Tuuholoaki's Quiz History_ Laboratory 1 _ Geologic Techniques

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University of Washington *

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101

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Geology

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Apr 3, 2024

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Laboratory 1 : Geologic Techniques Results for Fina Tuuholoaki  Answers will be shown after your last attempt Score for this attempt: 9 out of 11 Submitted Jan 17 at 2:33pm This attempt took 5,287 minutes.  Question 1 0.25 / 0.25 pts True False  Laboratory Honor Statement Cheating or plagiarism of any kind will not be tolerated in ESS 101. This includes copying answers from a friend or classmate, copying answers verbatim found on the internet or other literary sources, or copying any work that may answer the question being asked. Make sure you always use your own words when answering the questions in the homework and cite appropriate references if you use them to help you answer the question. Violations the academic code of conduct (https://www.washington.edu/cssc/for-students/academic-misconduct/) will will be reported to the UW Academic Misconduct representative for investigative review. I acknowledge that I have carefully read and understand the above statement regarding the consequences of cheating and plagiarism, and promise to complete my work in this class with honesty and integrity. Answer "True" below supporting your acknowledgement. Learning Goals By completing this lab, students will gain a deeper of understanding of how: Maps are used to convey important information on the Earth’s surface The geographic grid (latitude and longitude) is used to describe location on a map To read topographic maps and use the data for landscape analyses

 To construct a topographic profile and use it to interpret geomorphic processes To use aerial photographs and LiDAR imagery to interpret landscapes Introduction Geoscientists utilize many different techniques to study the Earth, and many of these techniques do not always involve fieldwork or direct sampling of the Earth’s surface. Before a geoscientist completes work in the field, s/he will often review maps or remote images to learn about the study area. For example, consider a geoscientist who is assessing the landslide hazard for a proposed housing development near a steep slope. S/he can gain valuable insights about the local rock type and nearby geologic structures by looking at a geologic map. Additionally, s/he could use aerial photographs to study local topography and identify evidence for past landslides or erosion. Geoscientists also often record their field data on maps so that it can be interpreted within a spatial context and shared with other geoscientists or the general public. In today’s lab, we will explore map-reading, aerial photo interpretation, and remote sensing techniques that are utilized by geoscientists to study the geologic landscapes and processes operating at the Earth’s surface. Many of these techniques will be integrated into future laboratory exercises. History of Maps A map is a two-dimensional representation of a portion of the Earth’s surface. Civilizations have used maps for over three thousand years; the earliest known map was made by the Babylonians in the 6 century BCE. The earliest maps were largely drawn to denote place names and general directions, often neglecting accuracy and scale. Figures 1-1A and 1-1B illustrate the simplicity of these early maps . Figures 1-1A and 1-1B: Babylonian map of the world (Fig. 1-1A) drawn on a clay tablet circa 500 B.C. The map represents ancient Babylon, the Euphrates River and surrounding ocean, which today comprises modern Iraq. Fig. 1-1B is a representation of an original Roman map entitled, Orbis th 1

Terrarum, drawn by Marcus Vipsanius Agrippa in 20 A.D. The ancient Roman map shows Europe, Asia and Africa surrounding the Mediterranean Sea. Following the decline of the Roman Empire, near the end of the 5th century A.D., innovation and advancement in cartography declined for almost 1000 years until the start of the Renaissance Period in the late 14 century. During the Renaissance Period, the Age of Exploration and Discovery brought about a need for increased accuracy in maps, particularly for navigational purposes as global trade and colonization increased. Figure 1-2 shows a world map, originally published by the Flemish cartographer Gerard Mercator in 1595, and subsequently published in Henricus Hondius’ Atlas in 1633 . Such maps provided valuable navigational information, such as latitude and longitude coordinates and the seasonal position of the overhead sun for seafaring explorers and traders. Figure 1-2: Hondius’ map of the world was depicted in two hemispheres bordered by the representation of the four elements of fire, air, water and land. Portraits of the Roman Emperor Julius Caesar, Claudius Ptolemy, a 2 century A.D. geographer, and the atlas’s first two publishers, Mercator and Hondius also adorn the map’s border. Over the past 500 years, the accuracy and detail of maps has improved greatly with technological advances in surveying equipment and the advent of aerial and satellite imagery. Figure 1-3 showcases recent satellite imagery of the United States at night, with major and minor population centers illuminated by light. th 2 nd

 Figure 1-3: A composite satellite photograph of the United States at night . 3 Topographic Maps A topographic map is a three-dimensional representation of the Earth’s surface, where surface elevation or topography is represented by contour lines . Topographic maps are used in the earth sciences because they present a reduced view of the Earth’s surface and show the size, shape, and interrelationships of the natural landscape. Being able to use topographic maps is an invaluable tool for many different professions, as well as for recreational hiking. This lab will help acquaint you with the different components of topographic maps and their potential application to geologic problems. Location

Figure 1-4: World globe showing latitude and longitude coordinates . Latitude and Longitude Most maps have a geographic coordinate grid, which can be used to determine location. The most commonly used coordinate system is latitude and longitude. Latitude is an angular distance measured north or south of the Earth’s equator, which is 0° latitude. It varies from 0° to 90° north and from 0° to 90° south (Figure 1-4). Lines of latitude encircle the Earth parallel to the equator and are called parallels because they are parallel to one another. Lines of longitude represent the angular distance measured east or west from the prime meridian (0° longitude), which passes through the Royal Astronomical Observatory in Greenwich, England. Lines of longitude range from 0° to 180° east and from 0° to 180° west (Figure 1-4). The international date line is the line represented by both 180° east and 180° west longitude. Lines of longitude are termed meridians and encircle the Earth in a direction perpendicular to the equator. Meridians of longitude converge at the North and South poles; thus, they are neither parallel nor equally spaced except along a given line of latitude. Ground distance represented by a degree or minute of longitude decreases poleward from the equator because of this convergence. Units of latitude and longitude are expressed in degrees (°), and further subdivided into minutes (60 minutes ['] = one degree), and seconds (60 seconds [''] = one minute). For example, Seattle is located at 47°27'00'' N, 122°18'00'' W. To accurately convey a specific location on the Earth’s surface, it is 4

important to state whether its latitude lies north or south of the equator and longitude lies east or west of the prime meridian. By convention, a location’s latitude is stated first, followed by its longitude coordinate. Scale Most maps represent a reduced image of a larger area. The amount of reduction is defined by a map’s scale and may be expressed in the following ways: (1) Graphic Scale : Scale is indicated by a calibrated bar or line. For example, the bar scale shown in Figure 1-5a represents a distance of two kilometers on the Earth’s surface. Figure 1-5a: Example of a graphic scale from a topographic map. (2) Fractional Scale : Scale is expressed as a fixed ratio between a distance measured on a map and an equal distance measured on the Earth’s surface. This ratio is termed the representative fraction . For example, a fractional scale of 1:24,000 indicates that one distance unit on the map (inches, feet, centimeters, etc.) equals 24,000 of the same distance units on the surface of the Earth (Figure 1-5b). Figure 1-5b : Example of a fractional scale from a topographic map. Magnetic Declination On the surface of the Earth the magnetic north pole (where a compass needle will point) is not the same location as the “true” or geographic north pole , which defines the earth’s axis of rotation. The angular distance between geographic and magnetic north at a given location represents its magnetic declination. Because magnetic declination varies over time and space, a symbol and explanation are provided on the lower margin of most U.S. Geological Survey (USGS) topographic maps (Figure 1-6). This symbol shows the magnetic declination for the center area of a topographic map at the time it was published or revised. Figure 1-6: USGS magnetic declination symbol. The star represents geographic north, GN is grid north, and MN is magnetic north. This symbol shows a magnetic declination of 16½°.

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