Bilek – Research

My main research interests focus on earthquake processes. Current study areas include one close to home in the New Mexico area, and more far-flung areas in the shallow subduction zones around the world. One common thread to most of my work is to examine important factors influencing the nature of seismicity.

Shallow Subduction Zone Earthquakes and Slow Ruptures
Much of my research deals with shallow seismicity in global subduction zones, with a particular focus on areas that have produced slow ruptures. A current project investigates this issue along the Nicaragua/Costa Rica margin, in the area of the 1992 tsunami earthquake and recently observed slow slip events (more information here). One recently completed NSF-funded project (with Heather DeShon at U. Memphis (CERI) and Bob Engdahl (U. Colorado) involved relocating earthquakes in the regions of past tsunami or slow ruptures and determining source characteristics of these relocated events to assess how common slow/long duration earthquakes are in these areas.

We are also currently using the unique on-shore/off-shore seismic network deployed off of the Cascadia subduction zone to detect repeating small magnitude earthquakes that may be influenced by spatial variations in the incoming and overriding plates.  The project webpage is located here.

Middle America Subduction Zone
I also have research interests in Central America tectonics, with a few projects currently underway in Costa Rica/Nicaragua.  Along with co-workers at UC-Santa Cruz, Los Alamos, Georgia Tech, and several Costa Rican seismologists, we are looking at many aspects of the shallow subduction zone processes along the Middle America trench. These projects include examining the role of variable subducting topography on earthquake rupture processes in the region, with a focus on specific geographic regions where local, temporary seismic networks recorded microseismicity. I am also just beginning a project with Mike Brudzinski at Miami University (Ohio) to examine earthquake source processes along an area of slow slip and tremor in Mexico.

Induced Seismicity and Other New Mexico Earthquakes
Earthquakes linked to hydrofracting or wastewater injection is an area of high interest nationally, and my students and I are currently working on better characterization of possible induced seismicity in several locations within the state of New Mexico and elsewhere.  During 2016, I participated in a community-led deployment of seismometers in central OK to explore induced seismicity in that state.  You can find out more about that experiment: http://www.iris.edu/hq/site/PAGE_static/4261

Another part of my research effort while at New Mexico Tech includes monitoring earthquakes in the state through the New Mexico Tech Seismological Observatory. Several students, both undergraduate and graduate, and I routinely locate earthquakes in the region of the Socorro Magma Body, a small active area that includes roughly half of all the seismicity in the state. These earthquake locations are combined with regional GPS observations to examine deformation of the magma body. We, together with Mark Murray at NMT, are also expanding the comparison of seismicity and deformation all along the Rio Grande Rift zone, in a collaborative project with Anne Sheehan and others at CU-Boulder.  In addition, we monitor seismicity throughout rest of the state using additional seismic stations in Carlsbad area.

In Feb 2015, we deployed a mixed array of both broadband sensors and 800 single channel node seismometers above the Socorro Magma Body to study the earthquakes and structure associated with the magma body deformation.  This project, in conjunction with UNM, Colorado State and IRIS PASSCAL, highlights the use of new instrument technology and deployment strategies.  Learn more about this project here and the deployment here. 

Using Seismology to Explore Hydrogeologic Processes
Also during the summer of 2016, my students and I worked with Andrew Luhmann (NMT hydrology faculty) to instrument a sinkhole system in SE Minnesota.  We recorded 3 artificial recharge events, namely pouring large volumes of water from a pool into the cave system, as well as a large rainstorm with our 12 seismic stations, and are currently analyzing the data for distinguishing signals related to the discharge and flow in the karst system.