Dr. Dunn

DR. ROBERT DUNN | ^{Associate Professor}

Current and Previous Research Projects

My group is involved in several areas of scientific research that revolve around studies of mid-ocean ridges, hot spots, and subduction zones. Study areas include the southern and northern East Pacific Rise, the northern Mid-Atlantic Ridge, the Reykjanes Ridge, the Arctic ridge system, the Lau subduction and back-arc spreading systems, the Icelandic hotspot, and the Hawai’ian hotspot. We are also dedicated to developing new seismic techniques to explore these systems. In offshoot work we are involved in studies of fin and blue whale populations via acoustic tracking methods.

Eastern Lau Spreading Center		Waveform Modeling of Surface Waves
	In 2009, my group carried out a 3-D seismic survey to investigate melt supply to the ridge and melt storage in crustal magma chambers.		The mid-ocean ridge waveguide: Low mantle velocities beneath mid-ocean ridges trap surface wave energy in a low-velocity waveguide.
Ultra-slow Spreading Mid-Ocean Ridges		Whale Tracking in the Eastern Tropical Pacific
	We investigate the upper mantle beneath ultraslow spreading ridges.		Blues whales emit repetitive low-frequency calls that allow us to track them on a network of ocean-bottom seismometers.
Reykjanes Ridge Mantle		The Mid-Atlantic Ridge Mantle
	Ridge-hotspot interaction: An analysis of surface waves reveals the effect that the Iceland hotspot has on mantle flow and melting beneath the adjacent Reykjanes ridge.		Mantle structure near hotspots suggests various degrees of plume influence.
3-D Anisotropic Body-Wave Tomography		Mid-Atlantic Ridge Magmatic System
	Anisotropic Joint Inversion (ANJI): A new method for the joint inversion of reflection and refraction travel time data for 3-D anisotropic structure with layer interfaces.		First complete 3-D anisotropic seismic image of a slow-spreading ridge reveals a modest magmatic system that forms via repeated dike injection into the crust.
Coastal Erosion in Hawai’i		Southern East Pacific Rise Mantle
	Within the last century, most of Maui’s beaches either narrowed or were completely lost. We compare several erosion-rate calculation methods.		New surface wave techniques reveal the nature of mantle upwelling beneath the southern East Pacific Rise.
Crustal Anisotropy due to Tensile Cracks		Mid-Ocean Ridge Hydrothermal Modeling
	Tensile cracks produce seismic anisotropy and may act as pathways for hydrothermal circulation to cool ridge magmatic systems.		Numerical models of hydrothermal systems support evidence for deep cooling of the magmatic system.
East Pacific Rise Magmatic System in 3-D		Mantle Melt Supply of the East Pacific Rise
	First complete 3-D seismic image of the magmatic system of a fast-spreading mid-ocean ridge. The seismic images reveal crustal melt storage and thermal structure.		Seismic images reveal the manner in which mantle melt is delivered to a fast-spreading ridge's crustal magmatic system.
Mantle Diapirs beneath Mid-Ocean Ridges?		Lava Flow Detection along the SEPR
	Mantle flow structures in the Oman ophiolite predict specific seismic anisotropic patterns that may be detectable with seismic techniques. Mantle flow structures in the Oman ophiolite predict specific seismic anisotropic patterns that may be detectable with seismic refraction methods.		Repeated wide-angle sonar surveying yield information on the frequency-magnitude relationship of volcanic eruptions on the seafloor.