← Back to Sessions

Insights Into Fault Interactions in Central New Zealand Using Paleoearthquake Records and Earthquake Simulators

Description: 

Forecasting the probability and magnitude of future large magnitude earthquakes is typically dependent on available paleo- and historical earthquake information. In Aotearoa-New Zealand (A-NZ) historical records (post 1840AD) demonstrate that many large earthquakes (e.g., >Mw 7.0) rupture multiple faults with complex rupture patterns and/or trigger additional earthquakes. To improve understanding of the importance of temporally clustered earthquakes, we compare the timing of earthquakes between active faults in central A-NZ using paleoseismic and historical records and a synthetic earthquake catalogue. To support this comparison we have revised paleoseismic records for key faults to determine the frequency of spatial-temporally clustered earthquakes. These short geological records (e.g., < 20 kyr) are compared to synthetic earthquake catalogues produced by physics-based RSQSim simulations for timescales of ~300 kyr. The paleo-record indicates that earthquakes on neighbouring faults are often close in age, suggesting spatio-temporal interactions between faults. Due to uncertainties in the radiocarbon dating, this clustering could arise from multi-fault ruptures and/or triggered slip in separate earthquakes. Both scenarios are represented in the RSQSim catalogues, with co-rupture of the Hikurangi subduction thrust and upper plate faults being common. Multi-fault and triggered earthquakes both suggest stress interactions between faults on timescales of seconds to hundreds of years and temporally variable seismic hazards. These fault interactions have important implications for time-dependent seismic hazard in central A-NZ and will be explored further using RSQSim models.

Session: From Geodynamics to Earthquake Rupture, Models That Cross Time- and Length-Scales - I

Type: Oral

Date: 5/3/2024

Presentation Time: 05:30 PM (local time)

Presenting Author: Jade

Student Presenter: Yes

Invited Presentation: 

Authors