Oblique Photogrammetric Analysis of Dome Growth at Mount St. Helens Volcano, 2004 – 2007

Author

Angela K. Diefenbach, Western Washington University

Date Permissions Signed

7-19-2018

Date of Award

Fall 2007

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Crider, Juliet G.

Second Advisor

Dzurisin, Daniel

Third Advisor

Caplan-Auerbach, Jacqueline

Fourth Advisor

Linneman, Scott

Abstract

This project is an oblique photogrammetric survey of the 2004-2007 dome-building eruption of Mount St. Helens volcano with two primary objectives: (1) to evaluate the potential of a new rapid and low-cost technique to create digital elevation models (DEMs) and subsequently calculate dome volumes and extrusion rates at Mount St. Helens; and (2) to attempt to understand mechanics associated with lava dome extrusion and collapse by analyzing volumetric and extrusion rate measurements in the context of dome height measurements, seismicity data, and migration of the locus of dome growth.

The new method uses sets of oblique aerial photographs, acquired from a helicopter with a standard digital camera, and commercially available photogrammetry software to create DEMs. Twelve sets of overlapping digital images from November 2004 to April 2007 of the growing dome inside the crater of Mount St. Helens were used to produce DEMs. Analyses of the digital images were carried out using PhotoModeler software, which produces three dimensional coordinates of points identified in multiple photos.

The DEMs were used for qualitative and quantitative descriptions of the 2004-2007 eruption. The DEMs were used to calculate height, volume, and extrusion rate, and to track changes in these quantities through time. These quantities show a decreasing extrusion rate through time that has remained lower than 1 m³/s since October 2005. Total dome volume had reached 94x10⁶ m³ as of April 2007, a larger volume than that of the 1980-1986 Dome. Quantitative evaluation of the DEMs also shows a relationship between dome height and extrusion rate, which varies with the character of eruptive activity.

Results were validated by comparing volume measurements derived from traditional aerophotogrammetric surveys run by the USGS Cascades Volcano Observatory. The new oblique photogrammetric technique yields estimates of eruptive volume consistently within 5% of the volumes estimated with traditional surveys. The end result of this project is a new technique that provides inexpensive, rapid assessment of volcanic activity that can be an important supplement to volcano monitoring worldwide.

Type

Text

Keywords

Digital elevation models, DEMs, Lava dome extrusion

Publisher

Western Washington University

OCLC Number

1060572543

Subject – LCSH

Domes (Geology)--Washington (State)--Saint Helens, Mount; Photographic surveying

Geographic Coverage

Saint Helens, Mount (Wash.)--Relief models

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

Recommended Citation

Diefenbach, Angela K., "Oblique Photogrammetric Analysis of Dome Growth at Mount St. Helens Volcano, 2004 – 2007" (2007). WWU Graduate School Collection. 785.
https://cedar.wwu.edu/wwuet/785