pericaLIGERA
Make sure to check out our blog as we complete our field campaign on the Nicoya Peninsula in Costa Rica!
In February and March 2023, we installed magnetotelluric receivers at 42 sites across the Nicoya Peninsula (see map below) to investigate the role of fluids on earthquake behavior. The west coast of Central America is a convergent plate boundary that regularly experiences large subduction zone earthquakes. In Nicoya Peninsula, Costa Rica, both large damaging earthquakes with significant ground shaking as well aseismic slow-slip events (SSEs) with little to no ground shaking have been observed.
Determining why some parts of the plate boundary experience megathrust rupture, while others experience SSEs is important in seismic hazard assessment. It is hypothesized that the style of fault slip may be driven by variations in subsurface fluid content, since fluid-rich zones can lubricate faults while fluid-poor zones promote stick-slip behavior. However, it is unclear precisely what combination of factors dictate the fault slip behavior or whether the hydrology and fluid content are alone responsible. To address these critical unknowns, this project will collect electromagnetic imaging data to constrain the subsurface hydrology and the distribution of fluids beneath the Nicoya Peninsula. The new data were collected in collaboration with Costa Rican partners and will help to distinguish the conditions that facilitate damaging earthquakes from conditions which promote aseismic slip.
