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## Calculating slope gradient variations in the submarine landforms by R and Python statistical libraries

#### Polina LEMENKOVA [1]

Multiple factors affect submarine geomorphology causing variations in the gradient slope: geological settings (rock composition, structure, permeability, erodibility of the materials), submarine erosion, gravity flows of water streams, tectonics, sediments from the volcanic arcs, transported by transverse submarine canyons. Understanding the slope geomorphology is important for the precise bathymetric mapping. However, analysis of such a complex geomorphic structure as ocean trench requires numerical computation and advanced statistical analysis of the data set. Such methods are proposed by R and Python programming languages that include libraries of machine learning algorithms for the data processing used in this research: {tidyverse}, {ggsignif}, {ggplot} and {magrittr} by R, StatsModels, Matplotlib, NumPy, Pandas and Seaborn by Python. The research workflow can be summarized in five steps: 1) Partial least squares regression analysis; 2) Violin plots, modified box plot approach; 3) Modelling variations of depth and slope gradient, facetted in multi-panel plots by 4 tectonic plates; 4) Calculating normalized steepness angle; 5) Sorting, ranking and grouping of the cross-sectioning profiles by gradient slope degree, to estimate differences in the geomorphic shapes. As a result of the ranking performed in step 5, slopes were classified into five classes based on the calculated tangent angles: strong, very strong, extreme, steep, very steep. The results show differences in the gradient slope between various segments of the Mariana Trench located in four tectonic plates: Mariana, Caroline, Pacific and Philippine Sea, performed by statistical data modelling. Programming codes and snippets are presented for repeatability of the methods in similar research tasks.

Geomorphology, Slope Calculation, Gradient, R, Python, Programming
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Primary Language en Engineering Research Article Orcid: 0000-0002-5759-1089Author: Polina LEMENKOVA (Primary Author)Institution: Ocean University of China, College of Marine Geo-sciencesCountry: China China Scholarship Council (CSC) 2016SOA002 This research was funded by the China Scholarship Council (CSC), State Oceanic Administration (SOA), Marine Scholarship of China, Grant Nr. 2016SOA002, People’s Republic of China. Publication Date : December 25, 2019
 Bibtex @research article { mjen560487, journal = {MANAS Journal of Engineering}, issn = {1694-7398}, eissn = {1694-7398}, address = {}, publisher = {Kyrgyz-Turkish Manas University}, year = {2019}, volume = {7}, pages = {99 - 113}, doi = {}, title = {Calculating slope gradient variations in the submarine landforms by R and Python statistical libraries}, key = {cite}, author = {LEMENKOVA, Polina} } APA LEMENKOVA, P . (2019). Calculating slope gradient variations in the submarine landforms by R and Python statistical libraries. MANAS Journal of Engineering , 7 (2) , 99-113 . Retrieved from https://dergipark.org.tr/en/pub/mjen/issue/50947/560487 MLA LEMENKOVA, P . "Calculating slope gradient variations in the submarine landforms by R and Python statistical libraries". MANAS Journal of Engineering 7 (2019 ): 99-113 Chicago LEMENKOVA, P . "Calculating slope gradient variations in the submarine landforms by R and Python statistical libraries". MANAS Journal of Engineering 7 (2019 ): 99-113 RIS TY - JOUR T1 - Calculating slope gradient variations in the submarine landforms by R and Python statistical libraries AU - Polina LEMENKOVA Y1 - 2019 PY - 2019 N1 - DO - T2 - MANAS Journal of Engineering JF - Journal JO - JOR SP - 99 EP - 113 VL - 7 IS - 2 SN - 1694-7398-1694-7398 M3 - UR - Y2 - 2019 ER - EndNote %0 MANAS Journal of Engineering Calculating slope gradient variations in the submarine landforms by R and Python statistical libraries %A Polina LEMENKOVA %T Calculating slope gradient variations in the submarine landforms by R and Python statistical libraries %D 2019 %J MANAS Journal of Engineering %P 1694-7398-1694-7398 %V 7 %N 2 %R %U ISNAD LEMENKOVA, Polina . "Calculating slope gradient variations in the submarine landforms by R and Python statistical libraries". MANAS Journal of Engineering 7 / 2 (December 2019): 99-113 . AMA LEMENKOVA P . Calculating slope gradient variations in the submarine landforms by R and Python statistical libraries. MJEN. 2019; 7(2): 99-113. Vancouver LEMENKOVA P . Calculating slope gradient variations in the submarine landforms by R and Python statistical libraries. MANAS Journal of Engineering. 2019; 7(2): 113-99.

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