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Structural Control on the Distribution of Earthquake Clusters Along the Northern Ecuadorian Margin

Description: 

High resolution studies reveal the complexity and diversity of structure and physical properties in subduction zones. Studies to date, particularly after the 2016 Mw 7.8 Pedernales megathrust rupture, indicate earthquake clustering and slip behaviors that host frequent seismic swarms and repeating earthquakes along the Ecuador subduction margin. Structure in the subducting and upper plate and frequent aseismic release of accumulated stress seem to play an important role in megathrust rupture. The HIPER Project (High Resolution Imaging of the Pedernales Earthquake Rupture Zone) is a large multidisciplinary international collaboration to image the plate interface in the megathrust region. As part of the Project, temporary deployments recorded passive and active sources over two years to study lateral heterogeneity downdip and along strike in the forearc. The passive recordings included the deployment of 59 broadband stations across the forearc from the coast to the foothills of the Andes. Two linear arrays of nodes spaced about 1 km apart during 1-month: 158 nodes along strike near the coast crossing the Punta Galera, Cojimíes-Atacames and Jama earthquake clusters and 141 nodes along a dip direction across the forearc above the subducting Carnegie Ridge. In 2022, active sources from a dense 2-D grid of marine airgun were recorded by 483 nodes deployed near the coast. This provides an exceptional opportunity for onshore/offshore multiscale 3D imaging of the northern Ecuador. Here we focus on the margin from Punta Galera to Jama. Using the dense deployments, we present the spatio-temporal distribution of seismicity during this period in context of long-term observations. The ultimate goal of these deployments is to obtain precise locations of seismic sources along the northern margin of the subduction zone to better characterize deformation and its potential connection to rheology and structures that appear in part to control megathrust rupture and earthquake clusters.

Session: Deciphering Earthquake Clustering for the Better Understanding of Crustal Deformation Mechanisms [Poster]

Type: Poster

Date: 4/20/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Gabriela Ponce

Student Presenter: Yes

Invited Presentation: 

Authors