Development of a high temporal resolution rockfall database using structure-from-motion photogrammetry and analyses of seasonal- and weather-rockfall relationships

Rockfall is the most common type of mass wasting event in mountainous regions or other areas of steep topography, and is a pervasive hazard that consistently impacts human lives and infrastructure. Understanding the relationship between rockfall and weather and seasonal patterns in rockfall activity can aid in developing hazard management and mitigation plans. Numerous studies have been performed to investigate these trends in a number of different geological and geographical environments. Many of these studies are limited in either the length of their monitoring period, the frequency at which data is collected, and/or their ability to reliably estimate rockfall volumes. To study rockfall processes, this thesis develops a high temporal resolution and high spatial resolution rockfall database for a section of rock slope located on the westbound lane of Interstate 70, west of Idaho Springs, Colorado. The slope is comprised of both a cut and natural portion of weathered metamorphic rock, and exhibits a relatively high rate of rockfall activity given its size. A permanent, fixed 5-camera photogrammetry system has been monitoring the site since March 2018 with automated twice-daily collection of photographs. An existing semi-automated workflow was adapted using recently developed photogrammetry point cloud creation methods to develop a rockfall database and characterize rockfall activity for an approximately 5.5 year study period. The analysis of the database shows that rockfall at the Idaho Springs slope varies substantially from season to season. Winter freezing processes in conjunction with spring snowmelt condition rock blocks for later mobilization. Increased liquid precipitation in the spring triggers rockfall as the slope thaws. Rockfall activity continues to be elevated over the summer as liquid precipitation remains high and rock blocks further destabilized by continued freeze-thaw cycling over the spring mobilize. Rockfall in the autumn is greatly reduced due to few remaining unstable blocks and a lack of continued slope conditioning over the summer. The Air Freezing Index and freezing intensity metrics utilized in this study support the hypothesis that more intensely cold winters result in increased rockfall activity in the following spring and summer.

Name thesis:degree_name

Master of Science (M.S.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Geology and Geological Engineering

Grantor dc:publisher

Colorado School of Mines. Arthur Lakes Library

Year dc:date.issued

2024

Author dc:creator

• Hollander, Jacob Andrew

Advisor dc:contributor.advisor

• Walton, Gabriel

Committee members dc:contributor.committeemember

• Singha, Kamini
• Zhou, Wendy

• photogrammetry
• rockfall
• seasonal
• SNODAS
• structure-from-motion
• weather

Statement dc:rights

• Copyright of the original work is retained by the author.

Language dc:language.iso

eng, English

Dc Identifier Other

T 9814

OAI identifier oai:identifier

oai:repository.mines.edu:11124/179216