Marine geology: Difference between revisions - Wikipedia

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== History ==

The study of marine geology dates back to the late 1800s during the 4-year HMS [[Challenger expedition|''Challenger'' expedition]].<ref name=":02">{{Cite web |last1=Heckel |first1=Jodi |last2=Bureau |first2=Illinois News |date=2023-02-10 |title=Exploring the deep with the HMS Challenger {{!}} College of Liberal Arts & Sciences at Illinois |url=https://las.illinois.edu/news/2023-02-10/exploring-deep-hms-challenger |access-date=2024-02-19 |website=las.illinois.edu |language=en}}</ref><ref name=":12">{{Citation |last=Board |first=National Research Council (US) Ocean Studies |title=Achievements in Marine Geology and Geophysics |date=2000 |work=50 Years of Ocean Discovery: National Science Foundation 1950—2000 |url=https://www.ncbi.nlm.nih.gov/books/NBK208827/ |access-date=2024-02-19 |publisher=National Academies Press (US) |language=en}}</ref> ~~The~~ HMS ''Challenger'' hosted nearly 250 people, including sailors, engineers, carpenters, marines, officers, and a 6-person team of scientists, led by [[Charles Wyville Thomson]].<ref name=":02" /><ref name=":22">{{Cite web |title=HMS Challenger Expedition {{!}} History of a Scientific Trailblazer |url=https://www.rmg.co.uk/stories/topics/hms-challenger-expedition-oceanography-trailblazer |access-date=2024-02-19 |website=www.rmg.co.uk |language=en}}</ref> The scientists' goal was to prove that there was life in the deepest parts of the ocean.<ref name=":22" /> Using a sounding rope, dropped over the edge of the ship, the team was able to capture ample amounts of data. Part of their discovery was that the deepest part of the ocean was not in the middle.<ref name=":12" /> These were some of the first records of the mid-ocean ridge system.{{Cn|date=April 2024}}

~~Preceding~~Prior to World War II, marine geology ~~was~~grew ~~becoming~~as ~~more~~a ~~prevalent~~scientific ~~to the science community~~discipline. During the early 20th- century, organizations such as the [[Scripps Institution of Oceanography]] and the [[Woods Hole Oceanographic Institution]] (WHOI) were created to support efforts in the field.<ref name=":32">{{Cite web |title=Who We Are - Woods Hole Oceanographic Institution |url=https://www.whoi.edu/who-we-are/ |access-date=2024-02-19 |website=www.whoi.edu/ |language=en-US}}</ref><ref name=":42">{{Cite web |title=About Scripps Oceanography |url=https://scripps.ucsd.edu/about |access-date=2024-02-19 |website=scripps.ucsd.edu |language=en}}</ref> With Scripps being located on the west coast of North America and WHOI on the east coast, the study of marine geology became much more accessible.<ref name=":32" /><ref name=":42" />

In the 1950s, marine geology had one of the most significant discoveries, the [[mid-ocean ridge]] system. After ships were equipped with sonar sensors, they travelled back and forth across the Atlantic Ocean collecting observations of the sea floor.<ref name=":52">{{Cite web |title=Seafloor spreading {{!}} Evidence & Process {{!}} Britannica |url=https://www.britannica.com/science/seafloor-spreading |access-date=2024-02-19 |website=www.britannica.com |language=en}}</ref> In 1953, athe cartographer [[Marie Tharp]] ~~was able to generate~~generated the first three -dimensional relief map of the ocean floor which ~~defined~~proved ~~the~~there ~~mountain~~was ~~range situated~~an underwater mountain range in the middle of the Atlantic, along with the [[Mid-Atlantic Ridge]].<ref>{{Cite web |last=Blakemore |first=Erin |date=30 August 2016 |title=Seeing Is Believing: How Marie Tharp Changed Geology Forever |url=https://www.smithsonianmag.com/history/seeing-believing-how-marie-tharp-changed-geology-forever-180960192/ |access-date=2024-04-17 |website=Smithsonian Magazine |language=en}}</ref> The survey data was large step towards many more discoveries about the geology of the sea.<ref name=":52" />

[[File:Oceanic.Stripe.Magnetic.Anomalies.Scheme.svg|thumb|A theoretical model of the formation of magnetic striping. New oceanic crust forming continuously at the crest of the mid-ocean ridge cools and becomes increasingly older as it moves away from the ridge crest with seafloor spreading.]]

~~Later, in~~In 1960, anthe American geophysicist ~~by the name of~~ [[Harry Hammond Hess|Harry H. Hess]] hypothesized that the seafloor was spreading from the mid -ocean ridge system.<ref name=":52" /> With support from the maps of the sea floor, and the recently developed theory of plate tectonics and [[continental drift]], Hess was able to prove that the [[Earth's mantle]] ~~continuous~~continuously released molten rock from the mid-ocean ridge and that the molten rock then solidified, causing the boundary between the two [[Plate tectonics|tectonic plates]] to [[Divergent boundary|diverge]].<ref name=":11">{{Cite web |title=Plate Tectonics |url=https://education.nationalgeographic.org/resource/plate-tectonics |access-date=2024-02-19 |website=education.nationalgeographic.org |language=en}}</ref> A geomagnetic survey was conducted that supported this theory. The survey was composed of scientists using [[magnetometer]]s to measure the magnetism of the [[Basalt Rocks|basalt rock]] protruding from the mid-ocean ridge.<ref name=":52" /><ref name=":62">{{Cite web |title=Seafloor Spreading |url=https://education.nationalgeographic.org/resource/seafloor-spreading |access-date=2024-02-19 |website=education.nationalgeographic.org |language=en}}</ref> They discovered that on either side of the ridge, symmetrical "strips" were found as the polarity of the planet would change over time.<ref name=":52" /><ref name=":62" /> This proved that [[seafloor spreading]] existed. In later years, newer technology was able to date the rocks and identified that rocks closest to the ridge were younger than the rocks near the coasts of the [[Western Hemisphere|Western]] and [[Eastern Hemisphere]]s land.

InAt ~~the modern days~~present, marine geology focuses on geological hazards, environmental conditions, habitats, natural resources, and energy and mining projects.<ref>{{Cite web |title=marine geology research: Topics by Science.gov |url=https://www.science.gov/topicpages/m/marine+geology+research |access-date=2024-02-19 |website=www.science.gov |language=en}}</ref>

== Methods ==

There are multiple methods for collecting data from the sea floor without physically dispatching humans or machines to the bottom of the ocean.

==== Side-scan sonar ====

A common method of collecting imagery of the sea floor is [[~~Side~~side-scan sonar]].<ref name=":72">{{Cite journal |last1=Johnson |first1=Paul |last2=Helferty |title=The geological interpretation of side-scan sonar |url=http://basin.earth.ncu.edu.tw/download/courses/seminar_MSc/2009/1008-2_The%20geological%20interpretation%20of%20side-scan%20sonar.pdf |journal=Reviews of Geophysics |date=1990 |volume=28 |issue=4 |pages=357–380|doi=10.1029/RG028i004p00357 |bibcode=1990RvGeo..28..357J }}</ref><ref name=":82">{{Cite web |title=Exploration Tools: Side-Scan Sonar: NOAA Office of Ocean Exploration and Research |url=https://oceanexplorer.noaa.gov/technology/sonar/side-scan.html |access-date=2024-02-19 |website=oceanexplorer.noaa.gov |language=en-US}}</ref> Developed in the late 1960s, the purpose of the survey method is to use active sonar systems on the sea floor to detect and develop images of objects.<ref name=":72" /> The physical sensors of the sonar device are known as a transducer array and they are mounted onto the hull of a vessel which sends acoustic pulses that reflect off the seafloor and received by the sensors. The imaging can help determine the seafloors composition as harder objects generate a stronger reflectance and appear dark on the returned image. Softer materials such as sand and mud cannot reflect the arrays pulses as well so they appear lighter on the image. This information can be analyzed by specialist to determine [[outcrop]]s of rock beneath the surface of the water.<ref name=":82" />

This method is less expensive than releasing a vehicle to take photographs of the sea floor, and requires ~~much~~ less time.<ref name=":82" /> The side-scan sonar is useful for ~~scientist~~scientists as it is a quick and efficient way of collecting imagery of the sea floor, but it cannot measure other factors, such as depth.<ref name=":72" /><ref name=":82" /> Therefore, other depth measuring sonar devices are typically accompanied with the side-scan sonar to generate a more detailed survey.<ref name=":72" />

==== Multibeam ~~Bathymetry~~bathymetry ====

Similarly to side-scan sonar, multibeam bathymetry uses a transducer array to send and receive ~~soundwaves~~sound waves in order to detect objects located on the sea floor.<ref name=":92">{{Cite web |title=Exploration Tools: Multibeam Sonar: NOAA Office of Ocean Exploration and Research |url=https://oceanexplorer.noaa.gov/technology/sonar/multibeam.html |access-date=2024-02-19 |website=oceanexplorer.noaa.gov |language=en-US}}</ref> Unlike, side-scan sonar, scientists are able to determine multiple types of measurements from the recordings and make hypothesis' on the data collected. By understanding the speed at which sound will travel in the water, scientists can calculate the two way travel time from the ship's sensor to the seafloor and back to the ship. These calculations will determine to depth of the sea floor in that area.<ref name=":92" />

[[File:Uracas_3d_hires.jpg|thumb|EM300 bathymetry of the three submarine volcanoes in the vicinity of Farallon de Pajaros Island. The data were collected using the EM300 multibeam system mounted on the hull of the R/V Thompson. The grid-cell size is 35 meters. The image is 2 times vertically exaggerated.]]

~~Furthermore,~~ [[~~backscatter~~Backscatter]] is another measurement used to determine the intensity of the sound that is returned to the sensor.<ref name=":92" /> This information can provide insight on the geological makeup and objects of the sea floor as well as objects located within the [[water column]]. Objects in the [[water column]] can include structures from shipwrecks, dense biology, and bubble plumes. The importance of objects in the water column to marine geology is identifying specific features as bubble plumes can indicate the presence of [[hydrothermal vent]]s and [[cold seep]]s.<ref name=":92" />

There are limitations to this technique. The distance between the sea floor and the sensor is related to the resolution of the map being created.<ref name=":92" /> The closer the sensor is the sea floor, the higher the resolution will be and the farther away the sensor is to the sea floor, the lower the resolution will be. Therefore, it is common for [[Remotely operated underwater vehicle|remotely operated vehicles]] (ROVs) and [[autonomous underwater vehicle]]s (AUVs) to be equipped with the multibeam sensor or for the sensor to be towed by the ship its self. This ensures that the resolution of the collected data will be ~~great~~high enough for proper analysis.<ref name=":92" />

==== Sub-bottom ~~Profiler~~profiler ====

A sub-bottom profiler is another sonar system used in [[geophysical survey]]s of the sea floor to not only map depth, but also to map beneath the sea floor.<ref name=":102">{{Cite web |title=Exploration Tools: Sub-Bottom Profiler: NOAA Office of Ocean Exploration and Research |url=https://oceanexplorer.noaa.gov/technology/sub-bottom-profiler/sub-bottom-profiler.html#:~:text=A%20sub-bottom%20profiler%20is,then%20reflected%20by%20subsurface%20sediment. |access-date=2024-02-19 |website=oceanexplorer.noaa.gov |language=en-US}}</ref> Mounted to the hull of a ship, the system releases low-frequency pulses which penetrate the surface of the sea floor and are reflected by sediments in the sub-surface. Some sensors can reach over ~~1000m~~1000 meters below the surface of the sea floor, giving hydrographers a detailed view of the marine geological environment.<ref name=":12" />

Many sub-bottom profilers can emit multiple frequencies of sound to record data on a multitude of [[sediment]]s and objects on and below the sea floor. The returned data is collected by computers and with aid from hydrographers, can create [[Cross section (geology)|cross-sections]] of the terrain below the sea floor.<ref name=":102" /> The resolution of the data also allows scientists to identify geological features such as [[Volcanic Ridge|volcanic ridges]], [[Submarine landslide|underwater landslides]], ancient river beds, and other features.<ref name=":102" />

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The benefit of the sub-bottom profiler is its capability to record information on the surface and below the seafloor. When accompanied with geophysical data from [[Multibeam echosounder|multibeam sonar]] and physical data from rock and [[core sample]]s, the sub-bottom profiles delivers insights on the location and morphology of submarine landslide, identifies how oceanic gasses travel through the subsurface, discover artifacts from cultural heritages, understand sediment deposition, and more.<ref name=":102" />

==== Marine ~~Magnetometry~~magnetometry ====

[[File:Magnetometer2004USNavy.jpg|thumb|A magnetometer used by the United States Navy in 2004.]]

Magnetometry is the process of measuring changes in the [[Earth's magnetic field]].<ref name=":13">{{Cite book |last1=Zhang |first1=Wentao |last2=Huang |first2=Wenzhu |last3=Luo |first3=Yingbo |last4=Li |first4=Fang |chapter=Simultaneous detection of deep-sea earthquake and magnetic field using three-axis fiber optic accelerometer-magnetometer |date=May 2019 |pages=1–5 |title=2019 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) |chapter-url=http://dx.doi.org/10.1109/i2mtc.2019.8826972 |publisher=IEEE |doi=10.1109/i2mtc.2019.8826972|isbn=978-1-5386-3460-8 }}</ref> The outer layer of the Earth's core is liquid and mostly made up of magnetic [[iron]] and [[nickel]].<ref>{{Cite journal |last=Loper |first=David E. |date=January 2000 |title=A model of the dynamical structure of Earth's outer core |url=http://dx.doi.org/10.1016/s0031-9201(99)00096-5 |journal=Physics of the Earth and Planetary Interiors |volume=117 |issue=1–4 |pages=179–196 |doi=10.1016/s0031-9201(99)00096-5 |bibcode=2000PEPI..117..179L |issn=0031-9201}}</ref> When the Earth turns on its axis, the metals release electrical currents which generate magnetic fields.<ref>{{Citation |title=The Earth's Magnetic Field |work=The Earth’s Magnetism |date=2006 |pages=1–66 |url=http://dx.doi.org/10.1007/978-3-540-27980-8_1 |access-date=2024-04-11 |publisher=Springer Berlin Heidelberg |doi=10.1007/978-3-540-27980-8_1 |isbn=978-3-540-27979-2}}</ref> These fields can then be measured to reveal geological subseafloor structures.<ref>{{Cite report ~~|url=http://dx.doi.org/10.4095/100974~~ |title=Geophysical reconnaissance of Hudson Bay Part I Sea-magnetometer Survey Part Ii Subbottom Depth Recorder Survey |last=Hood |first=P J |date=1966 |publisher=Natural Resources Canada/CMSS/Information Management|doi=10.4095/100974 |doi-access=free }}</ref> This method is especially useful in marine exploration and [[geology]] as it can not only characterize geological features on the seafloor but can survey aircraft and ship wrecks deep under the sea.<ref>{{Cite journal |last=Talwani |first=M. |date=October 1973 |title=Geomagnetism in marine geology |url=http://dx.doi.org/10.1016/0025-3227(73)90069-8 |journal=Marine Geology |volume=15 |issue=3 |pages=212–213 |doi=10.1016/0025-3227(73)90069-8 |bibcode=1973MGeol..15..212T |issn=0025-3227}}</ref>

A [[magnetometer]] is the main piece of equipment deployed, which is typically towed behind a vessel or mounted to a [[Autonomous underwater vehicle|AUV]]. It is able to measure the changes in fields of [[magnetism]] and corresponding geolocation to create maps.<ref>{{Cite ~~journal~~book |last1=Kostenko |first1=Vladimir V. |last2=Tolstonogov |first2=Anton Yu. |last3=Mokeeva |first3=Irina G. |~~date=April 2019 |title~~chapter=The Combined AUV Motion Control with Towed Magnetometer |date=April 2019 |title=2019 IEEE Underwater Technology (UT) |chapter-url=http://dx.doi.org/10.1109/ut.2019.8734468 ~~|journal=2019 IEEE Underwater Technology (UT)~~ |pages=1–7 |publisher=IEEE |doi=10.1109/ut.2019.8734468|isbn=978-1-5386-4188-0 }}</ref> The [[magnetometer]] evaluates the magnetic presence generally every second, or one [[hertz]], but can be calibrated to measure at different speeds depending on the study. The readings will be consistent until the device detects [[ferrous]] material.<ref>{{Cite web |title=Exploration Tools: Magnetometer: NOAA Office of Ocean Exploration and Research |url=https://oceanexplorer.noaa.gov/technology/magnetometer/magnetometer.html#:~:text=A%20magnetometer%20is%20a%20passive,geological%20features%20on%20the%20seafloor. |access-date=2024-04-11 |website=oceanexplorer.noaa.gov |language=en-US}}</ref> This could range from a [[Hull (watercraft)|ship's hull]] to ferrous [[basalt]] at the seafloor. The sudden change in magnetism can be analyzed on the magnetometer's display.<ref>{{Cite journal |last=Robbes |first=D. |date=May 2006 |title=Highly sensitive magnetometers—a review |url=http://dx.doi.org/10.1016/j.sna.2005.11.023 |journal=Sensors and Actuators A: Physical |volume=129 |issue=1–2 |pages=86–93 |doi=10.1016/j.sna.2005.11.023 |bibcode=2006SeAcA.129...86R |issn=0924-4247}}</ref>

The benefit to a magnetometer compared to sonar devices is its ability to detect artifacts and geological features on top and underneath the seafloor.<ref>{{Cite journal |last1=Deans |first1=Cameron |last2=Marmugi |first2=Luca |last3=Renzoni |first3=Ferruccio |date=2018-03-22 |title=Active underwater detection with an array of atomic magnetometers |url=http://dx.doi.org/10.1364/ao.57.002346 |journal=Applied Optics |volume=57 |issue=10 |pages=~~2346~~2346–2351 |doi=10.1364/ao.57.002346 |pmid=29714214 |arxiv=1803.07846 |bibcode=2018ApOpt..57.2346D |issn=1559-128X}}</ref><ref>{{Cite journal |last1=Clausen |first1=Carl J. |last2=Arnold |first2=J. Barto |date=May 1976 |title=The magnetometer and underwater archaeology |url=http://dx.doi.org/10.1111/j.1095-9270.1976.tb00953.x |journal=International Journal of Nautical Archaeology |volume=5 |issue=2 |pages=159–169 |doi=10.1111/j.1095-9270.1976.tb00953.x |bibcode=1976IJNAr...5..159C |issn=1057-2414}}</ref> Because the magnetometer is a passive sensor, and does not emit waves, its exploration depth is unlimited.<ref>{{Cite journal |last1=Li |first1=Xiaochen |last2=Luo |first2=Xianhu |last3=Deng |first3=Ming |last4=Qiu |first4=Ning |last5=Sun |first5=Zhen |last6=Chen |first6=Kai |date=March 2023 |title=Low-noise, low-power-consumption seafloor vector magnetometer |url=http://dx.doi.org/10.1007/s00343-022-2105-2 |journal=Journal of Oceanology and Limnology |volume=41 |issue=2 |pages=804–815 |doi=10.1007/s00343-022-2105-2 |bibcode=2023JOL....41..804L |issn=2096-5508}}</ref> Although, in most studies, the resolution and certainty of the data collected is dependent on the distance from the device. The closer the device is to a ferrous object, the better the data collected.

== Plate ~~Tectonics~~tectonics ==

[[File:Tectonic_plates_(2022).svg|thumb|334x334px|Map of Earth's principal [[Plate tectonics|tectonic plates]].]]{{Main articles|Plate tectonics}}

Plate tectonics is a scientific theory developed in the 1960s that explains major ~~landform~~land form events, such as [[Mountain formation|mountain building]], [[volcano]]es, [[earthquake]]s, and mid-ocean ridge systems.<ref name=":14">{{Citation |last=Condie |first=Kent C. |title=Plate tectonics |date=1997 |work=Plate Tectonics and Crustal Evolution |pages=1–35 |url=http://dx.doi.org/10.1016/b978-075063386-4/50001-x |access-date=2024-04-11 |publisher=Elsevier|doi=10.1016/b978-075063386-4/50001-x |isbn=978-0-7506-3386-4 }}</ref> The idea is that Earth's most outer layer, known as the [[lithosphere]], that is made up of the [[Crust (geology)|crust]] and [[Mantle (geology)|mantle]] is divided into extensive plates of rock.<ref name=":11" /><ref name=":14" /> These plates sit on top of partially molten layer of rock ~~know~~known as the [[asthenosphere]] and move relative to each other due to convection between the [[asthenosphere]] and lithosphere.<ref name=":14" /> The speed at which the plates move ranges between 2 and 15 centimeters per year. Why this theory is so significant is the interaction between the tectonic plates explains many geological formations.<ref name=":11" /> In regards to marine geology, the movement of the plates explains [[seafloor spreading]] and mid-ocean ridge systems, [[Subduction|subduction zones]] and trenches, volcanism and hydrothermal vents, and more.

There are three major types of tectonic plate boundaries; [[Divergent boundary|divergent]], [[Convergent boundary|convergent]], and [[Transform fault|transform boundaries]].<ref name=":15">{{Citation |last1=Frisch |first1=Wolfgang |title=Plate tectonics and mountain building |date=2010-11-02 |work=Plate Tectonics |pages=149–158 |url=http://dx.doi.org/10.1007/978-3-540-76504-2_11 |access-date=2024-04-11 |place=Berlin, Heidelberg |publisher=Springer Berlin Heidelberg |isbn=978-3-540-76503-5 |last2=Meschede |first2=Martin |last3=Blakey |first3=Ronald|doi=10.1007/978-3-540-76504-2_11 }}</ref> Divergent plate boundaries are when two tectonic plates move away from each other, convergent plate boundaries are when two plates move towards each other, and transform plate boundaries are when two plates slide sideways past each other. Each boundary type is associated with different geological marine features. Divergent plates are the cause for mid-ocean ridge systems while convergent plates are responsible for subduction zones and the creation of deep ocean trenches. Transform boundaries cause earthquakes, displacement of rock, and crustal deformation.<ref name=":1511" /><ref name=":1415" /><ref name=":1114" /><ref>{{Cite journal |last1=Silver |first1=Eli A. |last2=Cox |first2=Allan |last3=Hart |first3=Robert Brian |date=December 1986 |title=Plate Tectonics: How It Works |url=http://dx.doi.org/10.2307/3514713 |journal=PALAIOS |volume=1 |issue=6 |pages=615 |doi=10.2307/3514713 |jstor=3514713 |bibcode=1986Palai...1..615S |issn=0883-1351}}</ref>

=== Mid-ocean ~~Ocean~~ridge ~~Ridge System~~system ===

Divergent plates are directly responsible for the largest mountain range on Earth, known as the mid-ocean ridge system.<ref name=":16">{{Citation |last1=Searle |first1=R. C. |title=The Rheology and Morphology of Oceanic Lithosphere and Mid-Ocean Ridges |date=2013-03-19 |work=Mid-Ocean Ridges |pages=63–93 |url=http://dx.doi.org/10.1029/148gm03 |access-date=2024-04-11 |place=Washington, D. C. |publisher=American Geophysical Union |last2=Escartín |first2=J.|series=Geophysical Monograph Series |doi=10.1029/148gm03 |isbn=978-1-118-66587-9 }}</ref> At nearly 60,000 km long, the mid-ocean ridge is an extensive chain of underwater volcanic mountains that spans the globe.<ref name=":17">{{Cite web |last=US Department of Commerce |first=National Oceanic and Atmospheric Administration |title=What is the mid-ocean ridge?: Ocean Exploration Facts: NOAA Ocean Exploration |url=https://oceanexplorer.noaa.gov/facts/mid-ocean-ridge.html |access-date=2024-04-11 |website=oceanexplorer.noaa.gov |language=EN-US}}</ref> Centralized in the oceans, this unique geological formation houses a collection of [[ridge]]s, rifts, [[Fault (geology)|fault zones]], and other geological features.<ref name=":16" /><ref name=":17" />

The [[Mid-Atlantic Ridge]] is a consequence of the diverging [[North American Plate|North American]] and [[Eurasian Plate|Eurasian]], and the [[African Plate|African]] and [[South American Plate]]s.<ref name=":18">{{Cite journal |last1=Smith |first1=Deborah K. |last2=Cann |first2=Johnson R. |date=October 1993 |title=Building the crust at the Mid-Atlantic Ridge |url=http://dx.doi.org/10.1038/365707a0 |journal=Nature |volume=365 |issue=6448 |pages=707–715 |doi=10.1038/365707a0 |bibcode=1993Natur.365..707S |issn=0028-0836}}</ref> It began forming over 200 million years ago when the American, African and European continents were still connected, forming the [[Pangaea|Pangea]].<ref name=":19">{{Cite journal |last1=Fujiwara |first1=Toshiya |last2=Lin |first2=Jian |last3=Matsumoto |first3=Takeshi |last4=Kelemen |first4=Peter B. |last5=Tucholke |first5=Brian E. |last6=Casey |first6=John F. |date=March 2003 |title=Crustal Evolution of the Mid-Atlantic Ridge near the Fifteen-Twenty Fracture Zone in the last 5 Ma |url=http://dx.doi.org/10.1029/2002gc000364 |journal=Geochemistry, Geophysics, Geosystems |volume=4 |issue=3 |page=1024 |doi=10.1029/2002gc000364 |bibcode=2003GGG.....4.1024F |issn=1525-2027|hdl=1912/5774 |hdl-access=free }}</ref> After [[continental drift]], the ridge system became more defined and in the last 75 years, it has been intensely studied . The [[Mid-Atlantic Ridge~~|Mid-Atlantic Ridg~~]]~~<nowiki/>e~~ was also served as the birthplace for the discovery of [[seafloor spreading]].<ref name=":20">{{Cite journal |last1=Bird |first1=D.E. |last2=Hall |first2=S.A. |last3=Burke |first3=K. |last4=Casey |first4=J.F. |last5=Sawyer |first5=D.S. |date=2007 |title=Early Central Atlantic Ocean seafloor spreading history |url=http://dx.doi.org/10.1130/ges00047.1 |journal=Geosphere |volume=3 |issue=5 |pages=282 |doi=10.1130/ges00047.1 |bibcode=2007Geosp...3..282B |issn=1553-040X}}</ref> As volcanic activity produces new [[oceanic crust]] along the ridge, the two plates diverge from each other pulling up the new ocean floor from below the crust.<ref name=":18" /><ref name=":19" /><ref name=":20" /> Along the [[Continent-ocean boundary|ocean-continent]] border of the tectonic plates, the oceanic plates subduct underneath the continental plates, creating some of the deepest marine trenches in the world

[[File:Subduction-en.svg|thumb|416x416px|Diagram of the [[Geology|geological]] process of [[subduction]].]]

=== Subduction ~~Zones~~zones ===

[[Subduction|Subduction zones]] are caused when two tectonic plates [[Convergent boundary|converge]] on each other and one plate is pushed beneath the other.<ref>{{Citation |title=Subduction zones |work=SpringerReference |url=http://www.springerreference.com/index/doi/10.1007/springerreference_4233 |access-date=2024-04-11 |place=Berlin/Heidelberg |publisher=Springer-Verlag|doi=10.1007/springerreference_4233 |doi-broken-date=2024-04-11 }}</ref> In a marine setting, this typically occurs when the [[oceanic crust]] subducts below the [[continental crust]], resulting in volcanic activity and the development of deep ocean trenches.<ref>{{Cite journal |last1=Grevemeyer |first1=Ingo |last2=Ranero |first2=Cesar R. |last3=Ivandic |first3=Monika |date=2018-01-12 |title=Structure of oceanic crust and serpentinization at subduction trenches |url=http://dx.doi.org/10.1130/ges01537.1 |journal=Geosphere |volume=14 |issue=2 |pages=395–418 |doi=10.1130/ges01537.1 |bibcode=2018Geosp..14..395G |issn=1553-040X|hdl=10261/164536 |hdl-access=free }}</ref> Marine geology focuses on mapping and understanding how these processes function. Renowned geological features created through subduction zones include ~~The~~the [[Mariana Trench]] and the [[Ring of Fire]].<ref>{{Cite journal |last1=Zhang |first1=Jiangyang |last2=Zhang |first2=Fan |last3=Lin |first3=Jian |last4=Yang |first4=Hongfeng |date=September 2021 |title=Yield failure of the subducting plate at the Mariana Trench |url=http://dx.doi.org/10.1016/j.tecto.2021.228944 |journal=Tectonophysics |volume=814 |pages=228944 |doi=10.1016/j.tecto.2021.228944 |bibcode=2021Tectp.81428944Z |issn=0040-1951}}</ref><ref>{{Citation |last=Billen |first=Magali I. |title=Lithosphere–Mantle Interactions in Subduction Zones |date=2023 |work=Dynamics of Plate Tectonics and Mantle Convection |pages=385–405 |url=http://dx.doi.org/10.1016/b978-0-323-85733-8.00014-7 |access-date=2024-04-11 |publisher=Elsevier |doi=10.1016/b978-0-323-85733-8.00014-7 |isbn=978-0-323-85733-8}}</ref>

====== Mariana Trench ======

The [[Mariana Trench~~]] (or Marianas Trench)~~ is the deepest known submarine trench, and the deepest location in the Earth's crust itself.<ref name=":21">{{Cite journal |last1=Gardner |first1=James V. |last2=Armstrong |first2=Andrew A. |last3=Calder |first3=Brian R. |last4=Beaudoin |first4=Jonathan |date=2014-01-02 |title=So, How Deep ''Is'' the Mariana Trench? |url=http://dx.doi.org/10.1080/01490419.2013.837849 |journal=Marine Geodesy |volume=37 |issue=1 |pages=1–13 |doi=10.1080/01490419.2013.837849 |bibcode=2014MarGe..37....1G |issn=0149-0419}}</ref> It is a [[subduction zone]] where the [[Pacific Plate]] is being subducted under the [[Mariana Plate]].<ref name=":22" /> At the deepest point, the trench is nearly 11,000 m deep (almost 36,000 feet).<ref name=":21" /><ref name=":22" /> This is further below sea level than [[Mount Everest]] is above sea level, by over 2 kilometers.

[[File:Pacific_Ring_of_Fire.svg|thumb|Volcanic arcs and oceanic trenches partly encircling the Pacific Basin form the so-called Pacific Ring of fire, a zone of frequent earthquakes and volcanic eruptions.]]

====== Ring of Fire ======

The ~~[[Pacific~~ Ring of Fire~~|Ring of Fire]]~~ is situated around the [[Pacific Ocean]], created from several converging plate boundaries.<ref>{{Cite journal |last1=Embley |first1=Robert |last2=Baker |first2=Edward |last3=Butterfield |first3=David |last4=Chadwick |first4=William |last5=Lupton |first5=John |last6=Resing |first6=Joseph |last7=de Ronde |first7=Cornel |last8=Nakamura |first8=Ko-ichi |last9=Tunnicliffe |first9=Verena |last10=Dower |first10=John |last11=Merle |first11=Susan |date=2007-12-01 |title=Exploring the Submarine Ring of Fire: Mariana Arc - Western Pacific ~~|url=http://dx.doi.org/10.5670/oceanog.2007.07~~ |journal=Oceanography |volume=20 |issue=4 |pages=68–79 |doi=10.5670/oceanog.2007.07 |issn=1042-8275|doi-access=free }}</ref> Its intense [[volcanism]] and [[seismic]] activity poses a major threat for disastrous earthquakes, [[tsunami]]s, and volcanic eruptions.<ref>{{Cite web |title=Ring of Fire |url=https://education.nationalgeographic.org/resource/ring-fire |access-date=2024-04-11 |website=education.nationalgeographic.org |language=en}}</ref> Any [[early warning system]]s and mitigation techniques for these disastrous events will require marine geology of coastal and [[island arc]] environments to predict events.<ref>{{Cite journal |last1=Tupper |first1=Andrew |last2=Carn |first2=Simon |last3=Davey |first3=Jason |last4=Kamada |first4=Yasuhiro |last5=Potts |first5=Rodney |last6=Prata |first6=Fred |last7=Tokuno |first7=Masami |date=May 2004 |title=An evaluation of volcanic cloud detection techniques during recent significant eruptions in the western 'Ring of Fire' |url=http://dx.doi.org/10.1016/j.rse.2004.02.004 |journal=Remote Sensing of Environment |volume=91 |issue=1 |pages=27–46 |doi=10.1016/j.rse.2004.02.004 |bibcode=2004RSEnv..91...27T |issn=0034-4257}}</ref>

== Economic ~~Benefits~~benefits ==

=== Resource ~~Exploration~~exploration ===

Marine geology has several methods of detecting geological features below the sea.<ref name=":9212" /><ref name=":1392" /><ref name=":102" /><ref name=":1213" /> One of the ~~economical~~economic benefits of geological surveying of the seafloor is determining valuable resources that can be extracted.<ref>{{Cite journal |last1=Petersen |first1=Sven |last2=Hannington |first2=Mark |last3=Krätschell |first3=Anne |date=2017-01-03 |title=Technology developments in the exploration and evaluation of deep-sea mineral resources |url=http://dx.doi.org/10.3917/re1.085.0014 |journal=Annales des Mines - Responsabilité et environnement |volume=N° 85 |issue=1 |pages=14–18 |doi=10.3917/re1.085.0014 |issn=1268-4783}}</ref> The two major resources [[Deep sea mining|mined]] at sea include [[oil]] and ~~[[mineral]]s~~minerals. ~~and over~~Over the last 30 years, deep-sea mining has generated between $9 -$11 billion [[United States dollar|USD]] in the [[United States|United States of America]].<ref>{{Cite web |title="Who stands to benefit?" To engage in deep-sea mining or not. Not, say international scientists {{!}} Institute for the Oceans and Fisheries |url=https://oceans.ubc.ca/2023/11/08/who-stands-to-benefit-to-engage-in-deep-sea-mining-or-not-not-say-international-scientists/ |access-date=2024-04-11 |website=oceans.ubc.ca}}</ref><ref>{{Cite journal |last=Sharma |first=Rahul |date=2011-09-01 |title=Deep-Sea Mining: Economic, Technical, Technological, and Environmental Considerations for Sustainable Development |url=http://dx.doi.org/10.4031/mtsj.45.5.2 |journal=Marine Technology Society Journal |volume=45 |issue=5 |pages=28–41 |doi=10.4031/mtsj.45.5.2 |issn=0025-3324}}</ref> Although this sector seems profitable, it is a high risk, high reward industry with many harmful environmental impacts.<ref>{{Cite journal |last1=Peacock |first1=Thomas |last2=Alford |first2=Matthew H. |date=2018-04-17 |title=Is Deep-Sea Mining Worth It? |url=http://dx.doi.org/10.1038/scientificamerican0518-72 |journal=Scientific American |volume=318 |issue=5 |pages=72–77 |doi=10.1038/scientificamerican0518-72 |pmid=29672491 |bibcode=2018SciAm.318e..72P |issn=0036-8733}}</ref>

Some of the major minerals extracted from the sea include nickel, [[copper]], [[cobalt]], [[manganese]], [[zinc]], [[gold]], and other metals.<ref>{{Citation |last=Dick |first=Rolf |title=Deep-Sea Mining versus Land-Based Mining: A Cost Comparison |date=1985 |work=The Economics of Deep-Sea Mining |pages=2–60 |url=http://dx.doi.org/10.1007/978-3-642-70252-5_1 |access-date=2024-04-11 |place=Berlin, Heidelberg |publisher=Springer Berlin Heidelberg |doi=10.1007/978-3-642-70252-5_1 |isbn=978-3-642-70254-9}}</ref> These minerals are commonly formed around [[Volcanism|volcanic activity]], more specifically hydrothermal vents and [[Manganese nodule|polymetallic nodules]].<ref>{{Cite journal |last1=Van Dover |first1=C.L. |last2=Arnaud-Haond |first2=S. |last3=Gianni |first3=M. |last4=Helmreich |first4=S. |last5=Huber |first5=J.A. |last6=Jaeckel |first6=A.L. |last7=Metaxas |first7=A. |last8=Pendleton |first8=L.H. |last9=Petersen |first9=S. |last10=Ramirez-Llodra |first10=E. |last11=Steinberg |first11=P.E. |last12=Tunnicliffe |first12=V. |last13=Yamamoto |first13=H. |date=April 2018 |title=Scientific rationale and international obligations for protection of active hydrothermal vent ecosystems from deep-sea mining |url=http://dx.doi.org/10.1016/j.marpol.2018.01.020 |journal=Marine Policy |volume=90 |pages=20–28 |doi=10.1016/j.marpol.2018.01.020 |bibcode=2018MarPo..90...20V |issn=0308-597X|hdl=1721.1/134956.2 |hdl-access=free }}</ref><ref>{{Cite journal |last1=Kang |first1=Yajuan |last2=Liu |first2=Shaojun |date=2021-10-14 |title=The Development History and Latest Progress of Deep-Sea Polymetallic Nodule Mining Technology |journal=Minerals |volume=11 |issue=10 |pages=1132 |doi=10.3390/min11101132 |doi-access=free |bibcode=2021Mine...11.1132K |issn=2075-163X}}</ref> These vents emit large volumes of super-heated, metal infused fluids that rise and rapidly cool when mixed with the cold [[seawater]]. The [[chemical reaction]] causes [[sulfur]] and minerals to [[Precipitation (chemistry)|precipitate]] and from chimneys, towers, and mineral-rich deposits on the sea floor.<ref>{{Citation |title=Hydrothermal Systems and the Origin of Life |date=2021-11-09 |work=The Ecology of Deep-Sea Hydrothermal Vents |pages=397–412 |url=http://dx.doi.org/10.2307/j.ctv1zm2v35.17 |access-date=2024-04-11 |publisher=Princeton University Press|doi=10.2307/j.ctv1zm2v35.17 }}</ref> [[Manganese nodule|Polymetallic nodules]], also known as [[manganese nodule]]s, are rounded [[ore]]s formed over millions of years from precipitating metals from seawater and sediment pore water.<ref name=":23">{{Cite journal |last1=Hein |first1=James R. |last2=Koschinsky |first2=Andrea |last3=Kuhn |first3=Thomas |date=2020-02-24 |title=Deep-ocean polymetallic nodules as a resource for critical materials |url=http://dx.doi.org/10.1038/s43017-020-0027-0 |journal=Nature Reviews Earth & Environment |volume=1 |issue=3 |pages=158–169 |doi=10.1038/s43017-020-0027-0 |bibcode=2020NRvEE...1..158H |issn=2662-138X}}</ref> They are typically found unattached, spread across the abyssal seafloor and contain metals crucial for building batteries and touch screens, including cobalt, nickel, copper, and manganese.<ref name=":23" />

[[File:2015-04-14_18-20-14_Sonne_SO239_157ROV11_Logo_original(1).jpg|thumb|Manganese nodules on the seafloor in the Clarion-Clipperton zone. The image was taken with ROV KIEL 6000 during expedition SO239 with FS SONNE in April 2015.]]

A popular area for [[Deep sea mining|deep-sea mining]], located in the [[Pacific Ocean]], in the [[Clarion-Clipperton Zone|Clarion-Clipperton Zone (CCZ)]]. The ~~Clarion-Clipperton Zone, or Clarion-Clipperton Fracture Zone,~~CCZ is approximately 4,500,000 square kilometers constructed of various submarine [[fracture zone]]s.<ref name=":24">{{Cite journal |last1=Parianos |first1=John |last2=O’Sullivan |first2=Anthony |last3=Madureira |first3=Pedro |date=2022-03-02 |title=Geology of parts of the central and eastern Clarion Clipperton Zone ~~|url=http://dx.doi.org/10.1080/17445647.2022.2035267~~ |journal=Journal of Maps |volume=18 |issue=2 |pages=232–245 |doi=10.1080/17445647.2022.2035267 |bibcode=2022JMaps..18..232P |issn=1744-5647|doi-access=free }}</ref> It has been divided into 16 mining claims and 9 sections dedicated to conservation.<ref>{{Cite journal |last1=Lodge |first1=Michael |last2=Johnson |first2=David |last3=Le Gurun |first3=Gwenaëlle |last4=Wengler |first4=Markus |last5=Weaver |first5=Phil |last6=Gunn |first6=Vikki |date=November 2014 |title=Seabed mining: International Seabed Authority environmental management plan for the Clarion–Clipperton Zone. A partnership approach |url=http://dx.doi.org/10.1016/j.marpol.2014.04.006 |journal=Marine Policy |volume=49 |pages=66–72 |doi=10.1016/j.marpol.2014.04.006 |bibcode=2014MarPo..49...66L |issn=0308-597X}}</ref> According to the [[International Seabed Authority|International Seabed Authority (ISA)]], there is an estimated 21 billion tons (Bt) of nodules; 5.95 Bt of manganese, 0.27 Bt of nickel, 0.23 Bt of copper, and 0.05 Bt of cobalt. It is a highly sought-after area for mining because of the yield of minerals it ~~posses~~possesses.<ref name=":25">{{Cite web |last=US Department of Commerce |first=National Oceanic and Atmospheric Administration |title=DeepCCZ: Deep-sea Mining Interests in the Clarion-Clipperton Zone: NOAA Office of Ocean Exploration and Research |url=https://oceanexplorer.noaa.gov/explorations/18ccz/background/mining/mining.html |access-date=2024-04-11 |website=oceanexplorer.noaa.gov |language=EN-US}}</ref><ref>{{Cite web |date=2022-03-17 |title=Polymetallic Nodules - International Seabed Authority |url=https://www.isa.org.jm/exploration-contracts/polymetallic-nodules/ |access-date=2024-04-11 |language=en-US}}</ref>

=== Offshore ~~Energy~~energy ~~Development~~development ===

Marine geology also has many applications on the subject of offshore energy development.<ref>{{Cite thesis |title=THE ROLE OF FEDERALISM IN INITIATING OFFSHORE WIND DEVELOPMENT IN THE UNITED STATES AND EUROPE |url=http://dx.doi.org/10.23860/thesis-starr-clayton-2022 |publisher=University of Rhode Island |first=Clayton |last=Starr|date=2022 |doi=10.23860/thesis-starr-clayton-2022 }}</ref> Offshore energy is the generation of [[electricity]] using ocean-based resources. This includes using [[Wind power|wind]], [[thermal]]{{clarify|date=April 2024|reason=not hot air, nor [[thermal power]]?}}, [[wave]], and [[Tidal power|tidal]] movement to convert to energy.<ref>{{Cite journal |last1=Shouwei |first1=Zhou |last2=Qingping |first2=Li |last3=Haishan |first3=Zhu |last4=Houhe |first4=Zhang |last5=Qiang |first5=Fu |last6=Li |first6=Zhang |date=2016 |title=The Current State and Future of Offshore Energy Exploration and Development Technology |url=http://dx.doi.org/10.15302/j-sscae-2016.02.003 |journal=Chinese Journal of Engineering Science |volume=18 |issue=2 |pages=19 |doi=10.15302/j-sscae-2016.02.003 |doi-broken-date=2024-07-28 |issn=1009-1742}}</ref> Understanding the seafloor and geological features can help develop the [[infrastructure]] to support these [[Renewable energy|renewable energy sources]].<ref>{{Cite journal |last1=Guinan |first1=J. |last2=McKeon |first2=C. |last3=O'Keeffe |first3=E. |last4=Monteys |first4=X. |last5=Sacchetti |first5=F. |last6=Coughlan |first6=M. |last7=Nic Aonghusa |first7=C. |date=2020-09-09 |title=INFOMAR data supports offshore energy development and marine spatial planning in the Irish offshore via the EMODnet Geology portal ~~|url=http://dx.doi.org/10.1144/qjegh2020-033~~ |journal=Quarterly Journal of Engineering Geology and Hydrogeology |volume=54 |issue=1 |doi=10.1144/qjegh2020-033 |issn=1470-9236|doi-access=free }}</ref> Underwater geological features can dictate ocean properties, such as [[Current (fluid)|currents]] and [[temperature]]s, which are crucial for location placement of the necessary infrastructure to produce energy.<ref>{{Cite ~~journal~~book |last1=Yang |first1=Xu |last2=Bai |first2=Ke |~~date=November 2010 |title~~chapter=Development and prospects of offshore wind power |~~url~~date=~~http://dx.doi.org/10.1109/wnwec.~~November 2010~~.5673138~~ |~~journal~~title=2010 World Non-Grid-Connected Wind Power and Energy Conference |chapter-url=http://dx.doi.org/10.1109/wnwec.2010.5673138 |pages=1–4 |publisher=IEEE |doi=10.1109/wnwec.2010.5673138|isbn=978-1-4244-8920-6 }}</ref>

The stability of the seafloor is important for the creation of offshore [[wind turbine]]s.<ref>{{Cite journal |last1=Coughlan |first1=Mark |last2=Long |first2=Mike |last3=Doherty |first3=Paul |date=2020-06-03 |title=Geological and geotechnical constraints in the Irish Sea for offshore renewable energy |url=http://dx.doi.org/10.1080/17445647.2020.1758811 |journal=Journal of Maps |volume=16 |issue=2 |pages=420–431 |doi=10.1080/17445647.2020.1758811 |bibcode=2020JMaps..16..420C |issn=1744-5647}}</ref> Most turbines are secured to the seafloor using [[Deep foundation|monopiles]], if the water depth is greater than 15 meters.<ref name=":26">{{Cite journal |last1=Alsharedah |first1=Yazeed |last2=Naggar |first2=M.Hesham El |last3=Newson |first3=Timothy |date=2023 |title=A Compliance Model for Monopiles for Offshore Wind Turbines |url=http://dx.doi.org/10.2139/ssrn.4445231 |access-date=2024-04-11 |website=dx.doi.org|doi=10.2139/ssrn.4445231 }}</ref> There must be inserted in areas that are not at risk to [[Deposition (geology)|sediment deposition]], [[erosion]], or [[Tectonics|tectonic]] activity. [[Surveying]] the geological area before development is needed to insure proper support of the [[Wind turbine|turbines]] and forces applied to them.<ref name=":26" /> Another example why marine geology is needed for future energy projects is to understand [[wave]] and [[Current (water)|current]] patterns.<ref>{{Cite journal |last1=Nobre |first1=Ana |last2=Pacheco |first2=Miguel |last3=Jorge |first3=Raquel |last4=Lopes |first4=M.F.P. |last5=Gato |first5=L.M.C. |date=January 2009 |title=Geo-spatial multi-criteria analysis for wave energy conversion system deployment |url=http://dx.doi.org/10.1016/j.renene.2008.03.002 |journal=Renewable Energy |volume=34 |issue=1 |pages=97–111 |doi=10.1016/j.renene.2008.03.002 |bibcode=2009REne...34...97N |issn=0960-1481}}</ref> Analyzing the effects that the seafloor has on water movement can help support planning and location selection of generators offshore and optimize energy farming.<ref>{{Citation |title=Wave Energy Utilization in Europe: Current Status and Perspectives |date=2018-12-14 |work=Renewable Energy |pages=487–500 |url=http://dx.doi.org/10.4324/9781315793245-115 |access-date=2024-04-11 |publisher=Routledge|doi=10.4324/9781315793245-115 |isbn=978-1-315-79324-5 }}</ref>

== Environmental ~~Impacts~~impacts and ~~Mitigation~~mitigation ==

=== Habitat ~~Mapping~~mapping and ~~Conservation~~conservation ===

Marine ~~Geology~~geology has a key role in [[habitat]] mapping and conservation. With global events causing potentially irreversible damage to the sea habitats, such as [[Deep sea mining|deep-sea mining]] and [[bottom trawling]], marine geology can help us study and mitigate the ~~affects~~effects of these activity.<ref>{{Citation |last=Sharma |first=Rahul |title=Development of Environmental Management Plan for Deep-Sea Mining |date=2017 |work=Deep-Sea Mining |pages=483–506 |url=http://dx.doi.org/10.1007/978-3-319-52557-0_17 |access-date=2024-04-11 |place=Cham |publisher=Springer International Publishing |doi=10.1007/978-3-319-52557-0_17 |isbn=978-3-319-52556-3}}</ref>

The ~~[[Clarion-Clipperton Zone|~~CCZ]] has been surveyed and mapped to designate specific areas for mining and for conservation. The [[International Seabed Authority]] has set aside approximately 160,000 square kilometers of seabed within the CCZ as the area is rich with [[biodiversity]] and [[habitat]]s.<ref name=":24" /> The zone houses over 5,000 species, including [[sea cucumber]]s, [[coral]]s, [[crab]]s, [[shrimp]]s, [[Hexactinellid|glass sponges]], and members of the [[Spider|spider family]] and, has been an area where new species of [[sea worm]]s have been discovered.<ref name=":25" /> Furthermore, 90% of the species have yet to be identified.<ref>{{Cite web |date=2024-04-11 |title=These deep-sea animals are new to science—and already at risk |url=https://www.nationalgeographic.com/animals/article/deep-sea-animals-new-species-mining |access-date=2024-04-11 |website=Animals |language=en}}</ref> Proper marine survey techniques have protected thousands of habitats and species by dedicating it to conservation.

Bottom trawling also poses a detrimental effects to the sea and using marine geology techniques can be helpful at mitigating them.<ref>{{Cite journal |last1=Olsgard |first1=Frode |last2=Schaanning |first2=Morten T. |last3=Widdicombe |first3=Stephen |last4=Kendall |first4=Mike A. |last5=Austen |first5=Melanie C. |date=November 2008 |title=Effects of bottom trawling on ecosystem functioning |url=http://dx.doi.org/10.1016/j.jembe.2008.07.036 |journal=Journal of Experimental Marine Biology and Ecology |volume=366 |issue=1–2 |pages=123–133 |doi=10.1016/j.jembe.2008.07.036 |bibcode=2008JEMBE.366..123O |issn=0022-0981}}</ref> Bottom trawling, generally a [[commercial fishing]] technique, involves dragging a large net that herds and captures a target species, such as [[fish]] or crabs.<ref>{{Cite journal |last1=Althaus |first1=F |last2=Williams |first2=A |last3=Schlacher |first3=TA |last4=Kloser |first4=RJ |last5=Green |first5=MA |last6=Barker |first6=BA |last7=Bax |first7=NJ |last8=Brodie |first8=P |last9=Hoenlinger-Schlacher |first9=MA |date=2009-12-17 |title=Impacts of bottom trawling on deep-coral ecosystems of seamounts are long-lasting |url=http://dx.doi.org/10.3354/meps08248 |journal=Marine Ecology Progress Series |volume=397 |pages=279–294 |doi=10.3354/meps08248 |bibcode=2009MEPS..397..279A |issn=0171-8630}}</ref> During this process, the net damages the seafloor by scraping and removing animals and vegetation living on the seabed, including [[coral reef]]s, [[shark]]s, and [[sea turtle]]s.<ref>{{Cite journal |last=de Groot |first=S.J. |date=September 1984 |title=The impact of bottom trawling on benthic fauna of the North Sea |url=http://dx.doi.org/10.1016/0302-184x(84)90002-7 |journal=Ocean Management |volume=9 |issue=3–4 |pages=177–190 |doi=10.1016/0302-184x(84)90002-7 |bibcode=1984OcMan...9..177D |issn=0302-184X}}</ref> It can tear up [[root system]]s and animal [[burrow]]s, which can directly affect the sediment distribution.<ref>{{Cite journal |last1=Oberle |first1=Ferdinand K.J. |last2=Storlazzi |first2=Curt D. |last3=Hanebuth |first3=Till J.J. |date=July 2016 |title=What a drag: Quantifying the global impact of chronic bottom trawling on continental shelf sediment |url=http://dx.doi.org/10.1016/j.jmarsys.2015.12.007 |journal=Journal of Marine Systems |volume=159 |pages=109–119 |doi=10.1016/j.jmarsys.2015.12.007 |bibcode=2016JMS...159..109O |issn=0924-7963}}</ref> This can lead to the change in [[chemistry]] and [[Nutrition|nutriment]] levels in the sea water.<ref>{{Cite journal |last1=Oberle |first1=Ferdinand K.J. |last2=Swarzenski |first2=Peter W. |last3=Reddy |first3=Christopher M. |last4=Nelson |first4=Robert K. |last5=Baasch |first5=Benjamin |last6=Hanebuth |first6=Till J.J. |date=July 2016 |title=Deciphering the lithological consequences of bottom trawling to sedimentary habitats on the shelf |url=http://dx.doi.org/10.1016/j.jmarsys.2015.12.008 |journal=Journal of Marine Systems |volume=159 |pages=120–131 |doi=10.1016/j.jmarsys.2015.12.008 |bibcode=2016JMS...159..120O |issn=0924-7963}}</ref> Marine geology can determine areas which have been damaged to employ habitat ~~restoral~~restoration techniques. It can also help determine areas that have not been affecting by bottom trawling and employ conservation protection.

=== Sediment ~~Transportation~~transportation and ~~Coastal~~coastal ~~Erosion~~erosion ===

[[Sediment transport]]ation and [[coastal erosion]] is a complex subject that is necessary to understand to protect infrastructure and the environment.<ref>{{Citation |last1=Thomas Devlin |first1=Adam |title=Tidal Evolution Related to Changing Sea Level; Worldwide and Regional Surveys, and the Impact to Estuaries and Other Coastal Zones |date=2020-03-25 |work=Estuaries and Coastal Zones - Dynamics and Response to Environmental Changes ~~|url=http://dx.doi.org/10.5772/intechopen.91061 |access-date=2024-04-11~~ |publisher=IntechOpen |last2=Pan |first2=Jiayi|doi=10.5772/intechopen.91061 |isbn=978-1-78985-579-1 |doi-access=free }}</ref> [[Coastal erosion]] is the process of sediment and materials breaking down and transported due to the effects of the [[sea]].<ref>{{Cite journal |last=Swift |first=Donald J. P. |date=July 1968 |title=Coastal Erosion and Transgressive Stratigraphy |url=http://dx.doi.org/10.1086/627342 |journal=The Journal of Geology |volume=76 |issue=4 |pages=444–456 |doi=10.1086/627342 |bibcode=1968JG.....76..444S |issn=0022-1376}}</ref> This can lead to destruction animal habitats, fishing industries, and infrastructure.<ref>{{Citation |last1=Haj-Amor |first1=Zied |title=Climate Change and Coastal Erosion |date=2020-01-22 |work=Climate Change Impacts on Coastal Soil and Water Management |pages=115–123 |url=http://dx.doi.org/10.1201/9780429356667-10 |access-date=2024-04-11 |place=First edition. {{!}} Boca Raton, FL : CRC Press/ Taylor & Francis Group, 2020. |publisher=CRC Press |isbn=978-0-429-35666-7 |last2=Bouri |first2=Salem|doi=10.1201/9780429356667-10 }}</ref> In the United States, damages to properties and infrastructure has caused approximately $500 million per year, and an additional $150 million a year is dedicated to mitigation from the [[Federal government of the United States|U.S. federal government]].<ref>{{Cite web |title=Coastal Erosion {{!}} U.S. Climate Resilience Toolkit |url=https://toolkit.climate.gov/topics/coastal-flood-risk/coastal-erosion |access-date=2024-04-11 |website=toolkit.climate.gov}}</ref> Marine geology supports the study of sediment types, [[Current (fluid)|current patterns]], and [[Seabed|ocean topography]] to predict erosional trends which can protect these environments.<ref>{{Cite book |date=2018-02-06 |title=Handbook of Coastal Processes and Erosion |url=http://dx.doi.org/10.1201/9781351072908 |doi=10.1201/9781351072908|isbn=978-1-351-07290-8 }}</ref>

=== Natural ~~Hazard~~hazard ~~Assessment~~assessment ===

[[File:2004_Indonesia_Tsunami_Complete.gif|thumb|Model of the earthquake epicenter and tsunami extent of the 2004 Indian Ocean earthquake]]

Earthquakes are one of the most common [[natural disaster]]s.<ref name=":27">{{Cite journal |date=2013 |title=Large earthquakes may trigger more earthquakes |url=http://dx.doi.org/10.1063/pt.5.026947 |journal=Physics Today |issue=4 |page=3634 |doi=10.1063/pt.5.026947 |bibcode=2013PhT..2013d3634. |issn=1945-0699}}</ref> Furthermore, they can cause other disasters ~~to form as well~~, such as tsunamis and [[landslide]]s~~.<ref>{{Citation~~, ~~|title=Mechanics~~such ofas ~~earthquakes~~the ~~|date=2002-05-02~~[[2004 ~~|work=The~~Indian ~~Mechanics~~Ocean ~~of Earthquakes~~earthquake and ~~Faulting~~ tsunami|~~pages=179–243~~underwater ~~|url=http://dx.doi.org/10.1017/cbo9780511818516.006~~earthquake ~~|access-date=2024-04-11~~in ~~|publisher=Cambridge~~the ~~University~~Indian ~~Press|doi=10.1017/cbo9780511818516.006~~Ocean]] ~~|isbn=978-0-521-65223-0~~occurred ~~}}</ref>~~at ~~Typically, earthquakes form from movement between two tectonic plates or between~~a [[~~Fault~~Magnitude (~~geology~~earthquake)|~~fault lines~~magnitude]]~~.<ref~~ ~~name=":27"~~of ~~/> The ocean is home to several plate boundaries~~9.1 which ~~causes~~then ~~frequent~~triggered ~~and~~a ~~major~~tsunami ~~earthquakes,~~that ~~and~~caused ~~potential~~waves ~~tsunamis.<ref>{{Cite~~to ~~journal~~reach ~~|last1=Scholz~~a ~~|first1=Christopher H. |last2=Tan |first2=Yen Joe |last3=Albino |first3=Fabien |date=2019-06-07 |title=The mechanism~~height of ~~tidal triggering of earthquakes~~ at ~~mid-ocean~~least ~~ridges~~30 ft ~~|url=http://dx.doi.org/10.1038/s41467-019-10605-2~~and ~~|journal=Nature~~killed ~~Communications~~approximately ~~|volume=10 |issue=1 |page=2526 |doi=10.1038/s41467-019-10605-2 |pmid=31175308 |arxiv=1812.00639 |bibcode=2019NatCo..10.2526S |issn=2041-1723}}</ref> For example~~230,000 ~~in December 2004, an [[2004 Indian Ocean earthquake and tsunami|underwater earthquake~~people in ~~the~~13 ~~Indian~~different ~~Ocean]] occurred at a [[Magnitude (earthquake)|magnitude]] of 9.1~~countries.<ref>{{Cite journal |last1=Rajendran |first1=C. P. |last2=Rajendran |first2=K. |last3=Anu |first3=R. |last4=Earnest |first4=A. |last5=Machado |first5=T. |last6=Mohan |first6=P. M. |last7=Freymueller |first7=J. |date=2007-01-01 |title=Crustal Deformation and Seismic History Associated with the 2004 Indian Ocean Earthquake: A Perspective from the Andaman-Nicobar Islands |url=http://dx.doi.org/10.1785/0120050630 |journal=Bulletin of the Seismological Society of America |volume=97 |issue=1A |pages=S174–S191 ~~|doi=10.1785/0120050630~~ |bibcode=2007BuSSA..97S.174R |doi=10.1785/0120050630 |issn=0037-1106}}</ref> ~~This event triggered a tsunami that caused waves to reach a height of 30 ft or more and killed approximately 230,000 people in 13 different countries.~~<ref>{{Cite web |last=Reid |first=Kathryn |date=2023-09-25 |title=2004 Indian Ocean Earthquake and Tsunami: Facts and FAQs |url=https://www.worldvision.org/disaster-relief-news-stories/2004-indian-ocean-earthquake-tsunami-facts |access-date=2024-04-11 |website=World Vision |language=en-US}}</ref> ~~These events are deadly and have significant impact on people, infrastructure and the environment alike.~~ Marine geology and understanding plate boundaries supports the development of [[early warning system]]s and other mitigation techniques to protect the people and environments who may be susceptible to [[natural disaster]]s.<ref>{{Cite journal |last1=Šepić |first1=J. |last2=Vilibić |first2=I. |date=2011-01-05 |title=The development and implementation of a real-time meteotsunami warning network for the Adriatic Sea |journal=Natural Hazards and Earth System Sciences |volume=11 |issue=1 |pages=83–91 |doi=10.5194/nhess-11-83-2011 |doi-access=free |bibcode=2011NHESS..11...83S |issn=1684-9981}}</ref> Many [[Earthquake early warning system|~~Earthquake~~earthquake ~~Early~~early ~~Warning~~warning systems]] (~~EEW~~EEWS) ~~systems~~ are in place and more are being developed.<ref>{{Cite journal |last1=Schlesinger |first1=Angela |last2=Kukovica |first2=Jacob |last3=Rosenberger |first3=Andreas |last4=Heesemann |first4=Martin |last5=Pirenne |first5=Benoît |last6=Robinson |first6=Jessica |last7=Morley |first7=Michael |date=2021-08-04 |title=An Earthquake Early Warning System for Southwestern British Columbia |journal=Frontiers in Earth Science |volume=9 |page=657 |doi=10.3389/feart.2021.684084 |doi-access=free |bibcode=2021FrEaS...9..657S |issn=2296-6463}}</ref><ref>{{Cite journal |last1=Cremen |first1=Gemma |last2=Bozzoni |first2=Francesca |last3=Pistorio |first3=Silvia |last4=Galasso |first4=Carmine |date=February 2022 |title=Developing a risk-informed decision-support system for earthquake early warning at a critical seaport |url=http://dx.doi.org/10.1016/j.ress.2021.108035 |journal=Reliability Engineering & System Safety |volume=218 |pages=108035 |doi=10.1016/j.ress.2021.108035 |issn=0951-8320}}</ref>

== Future ~~Scientific Research~~research ==

=== Seafloor ~~Mapping~~mapping and ~~Bathymetry~~bathymetry ===

~~The~~Many ~~[[ocean]] covers over 70%~~section of the ~~Earth's~~oceans ~~surface~~are ~~and~~permanently ~~the~~dark, ~~[[ecosystem]]~~low ~~within is the largest~~temperatures, and ~~most~~are ~~abundant~~under inextreme ~~the~~pressure, ~~world.<ref~~making name=":28">{{Cite web |title=Seafloor Mapping |url=https://oceanexplorer.noaa.gov/explainers/mapping.html |access-date=2024-04-11 |website=oceanexplorer.noaa.gov |language=en-US}}</ref> The difficulty with studying the ocean is that it isthem ~~hard~~difficult to observe.<ref name=":29">{{Cite web |title=Boldly Explore Where No One Has Explored Before {{!}} Bureau of Ocean Energy Management |url=https://www.boem.gov/newsroom/ocean-science-news/boldly-explore-where-no-one-has-explored#:~:text=Today,%20over%2080%25%20of%20the,to%20explore%20the%20vast%20ocean. |access-date=2024-04-11 |website=www.boem.gov}}</ref~~> Many section of the ocean are permanently dark, low temperatures, and are under extreme pressure.<ref name=":29" /~~> According to the [[National Oceanic and Atmospheric Administration~~|National Oceanic and Atmospheric Administration~~]] (NOAA)]], only 23% of the seafloor has been mapped in detail and one of the leading projects in exploration is developing high-resolution maps of the seafloor. The ''[[NOAAS Okeanos Explorer|Okeanos Explorer]]'', a vessel owned by ~~[[National Oceanic and Atmospheric Administration|~~NOAA]], has already mapped over 2 million ~~km2~~km<sup>2</sup> of the seafloor using [[Multibeam echosounder|multibeam sonar]] since 2008, but this technique has proved to be too time-consuming.<ref name=":28">{{Cite web |title=Seafloor Mapping |url=https://oceanexplorer.noaa.gov/explainers/mapping.html |access-date=2024-04-11 |website=oceanexplorer.noaa.gov |language=en-US}}</ref>

The importance of mapping the seafloor has been recognized by governments and scientists alike. Because of this, an international collaboration effort to create a high-definition map of the entire seafloor was developed, called the [[Nippon Foundation-GEBCO Seabed 2030 Project]]. This committee has a set goal to have the project finished by 2030. To reach their goal, they are equipping old, new, and [[Vehicular automation|autonomous vehicles]] with [[sonar]], [[sensor]]s, and other [[Geographic information system|GIS]] ~~base~~based technology to reach their goal.<ref name=":28" />

==See also ==

Line 112:

* [[Hawaiian-Emperor seamount chain]]

* [[Hydrogeology]]

* [[List of geologists]]

* [[Pelagic sediments]]

* [[Seafloor mapping]]