The project supported seismology research into mantle and crust structure beneath North America and changes in earthquake activity in the Raton Basin natural gas field, which overlaps the New Mexico-Colorado border. Structural imaging studies used a variety of seismic wave types and refined processing methods to constrain processes hidden deep beneath the surface including: mineral phase transitions and subduction of oceanic plates hundreds of kilometers deep in the mantle, ductile stretching of hot lower to middle continental crust, and development of upper crustal magma reservoirs beneath major volcanic fields. These seismic imaging studies were largely enabled by continental-scale observations from the NSF's EarthScope Program, which provided continuous sampling across the lower 48 states and Alaska that could be combined with denser local networks. Thus, the research was conducted at a time when it was becoming possible to obtain new multi-scale views of fundamental tectonic and magmatic processes. Highlights among the results include: better constraining the extent of subducted slab segments beneath Alaska, identifying localized areas where mantle flow between slabs makes the speed of seismic waves vary with direction, and identifying that multiple large silica-rich magma reservoirs in the western U.S. crust are organized into horizontal layers of more concentrated melt. The local-scale portion of the project focused on evolving seismicity in the Raton Basin, where the frequency of magnitude greater than 3 earthquakes dramatically increased along with injection of wastewater from natural gas production and reached a peak with a magnitude 5.3 earthquake in 2011. University of New Mexico project members collected the first open-access seismic data from the Raton Basin for six years between 2016-2022 and their research illuminated the complex network of faults that have been reactivated by fluid injection. The results show that short distinct faults host most earthquakes in the basin, but multiple segments may combine to slip in relatively large events. Additionally, the bulk statistics of earthquake sequences are similar to those in naturally driven tectonic settings. The cumulative science results have been communicated in 15 peer-reviewed publications and dozens of conference presentations, primarily with graduate students and postdoctoral scholars as the first authors. 

Over the course of the project several graduate students (MS and PhD) and postdoctoral scholars received training in modern seismic data processing and integrative Earth science investigation. Two undergraduate student researchers were lead or co-authors of peer-reviewed publications and proceeded to graduate school in Earth science or engineering. 

Broader impacts included new contributions to undergraduate education, public outreach about earthquakes in New Mexico, participation in and development of extra-curricular STEM events for K-12 students, and middle school classroom visits to teach about earthquakes in New Mexico and career opportunities in geophysics. A new data analysis class was developed for undergraduate geoscience majors at the University of New Mexico, in which students gain experience accessing large public geoscience data sets and performing computational analyses to reveal environmental or geological processes. The class was designed in in-person and remote formats based on the evolving public health circumstances during the project. Public outreach was enhanced through a general-audience publication on fluid injection-induced earthquake activity in New Mexico. K-12 extra-curricular STEM events included participation in multiple science fair style events, development of a remote-format Science Olympiad event, and demonstration of modern seismic instruments and real-time data at a STEM open house. Several middle school classroom visits were used to teach middle school students about earthquakes in New Mexico and how fluid injection can influence fault slip that creates earthquakes.

Last Modified: 10/28/2022
Modified by: Brandon Schmandt