Semester of Graduation

Summer 2024


Master of Science (MS)


Geology and Geophysics

Document Type



Elastic properties of unconsolidated sediments depend on parameters such as porosity, grain texture (i.e., grain shape and sizes), sorting and coordination number. Coordination is the average number of grains each grain has with touching grains, is a critical parameter in rock physics models for estimating elastic moduli of materials. While previous works have focused on the influence of porosity and sorting on coordination numbers within well-rounded grains, natural sediments have a wide range of grain shapes and sizes, and it remains unclear how these parameters influence coordination numbers within angular unconsolidated sediments.

We investigate the impact of porosity, sorting and grain size on coordination numbers within angular unconsolidated sediments. Using micro-computed X-ray imaging tomography, we quantify the grain size, sorting, porosity and coordination numbers within three samples of angular unconsolidated sediments ranging from very coarse sand to medium sand. To understand the influence of these parameters on seismic properties within unconsolidated sediments, we predict seismic velocities using the Hertz-Mindlin rock physics model.

Our results show that coordination numbers are higher in well-sorted samples than in poorly sorted samples. However, porosity has little statistical influence on coordination number estimates. Predicted seismic velocities within well-sorted samples are higher than seismic velocities within poorly sorted samples. We propose a relationship between coordination numbers and sorting that can enhance the prediction of seismic velocities within angular unconsolidated sediments with varying degrees of sorting.



Committee Chair

Lorenzo, Juan

Available for download on Saturday, May 10, 2025