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How Comparable Are Frequency-Magnitude Variations of Natural and Induced Seismic Sequences? A Comparison for the Tectonic Gyeongju and Induced Pohang Earthquake Sequences.

Description: 

Induced seismic events are driven by anthropogenic, external forcing that increases stress and/or reduces the strength on seismogenic faults. One of the main processes inducing earthquakes are elevated fluid pressures related to industrial fluid injection. In contrast, natural events are the result of stationary plate tectonic motions causing constant stressing of a seismogenic fault. Though the stressing history of induced seismic sequences are fundamentally different from tectonic, the fluids predominantly trigger the release of pre-existing tectonic stress. Hence, an important question from a seismic hazard point of view is the extend to which the evolution of the seismic sequences is set by the elevated fluid pressures.

To gain insight into the fundamental impact of the physics controlling the evolution of natural and induced seismic sequences, we assess the observed spatial and temporal patterns of faulting and the frequency-magnitude distribution evolution of the fore- and aftershock sequence of the 2016 M_w5.4 Gyeongju tectonic earthquake and the 2017 M_w5.5 Pohang induced event. We particularly concentrate on the spatio-temporal evolution of the foreshock sequence, as the identification of a fundamental influence of the elevated fluid pressures could provide important indications for early mitigation of potential future induced events due to fluid injection.

Session: Understanding and Managing Induced Seismicity

Type: Oral

Date: 4/19/2023

Presentation Time: 10:45 AM (local time)

Presenting Author: Annemarie G. Muntendam-Bos

Student Presenter: No

Invited Presentation: 

Authors