Find a summary of my publications below:


Offshore tectonic tremor associated with the 2014 Gisborne SSE.

Earthquakes and Tremor Linked to Seamount Subduction During Shallow Slow Slip at the Hikurangi Margin, New Zealand


Erin K. Todd, Susan Y. Schwartz, Kimihiro Mochizuki, Laura M. Wallace, Anne F. Sheehan, Spahr C. Webb, Charles A. Williams, Jenny Nakai, Jefferson Yarce, Bill Fry, Stuart Henrys, Yoshihiro Ito

Year, Journal:

2018, Journal of Geophysical Research Letters - Solid Earth

Key Points:

  • Offshore tectonic tremor localises at subducted seamounts during and immediately following the 2014 Gisborne SSE

  • Stresses from seamount subduction dominate megathrust slow slip in producing seismicity and tremor

  • A wide range of slip processes occur on the plate interface in very close proximity to one another


Location of the investigated seismic reflection line 05CM‐04 with cumulative slip on the interface and tectonic tremor for the September–October 2014 slow slip event



Daniel H. N. Barker, Stuart Henrys, Fabio Caratori Tontini, Philip M. Barnes, Dan Bassett, Erin Todd, and Laura Wallace

Year, Journal:

2018, Geophysical Research Letters

Key Points:

  • Seismic images reveal Hikurangi margin accretionary wedge architecture and seismic velocity distribution

  • Magnetic anomaly modelling shows seismic tremor focused on the landward flanks and downdip of subducting seamounts

  • Structural heterogeneity of the plate interface may influence the distribution of slow slip and tremor


Seismic network for passive seismic experiment.

Purple circles are location of the three stations. Each station contained 6 seismometers. Active faults from NZ Active fault database (Langridge et al., 2016). Inactive faults as per regional geological mapping (Bishop and Turnbull, 1996; Forsyth, 2001)

Unknown faults under cities


Pilar Villamor, David J. A. Barrell, Andrew Gorman, B. Davy, B. Fry B, S. Hreinsdottir, I. Hamling, M. Stirling, S. Cox, N. Litchfield, A. Holt, Erin Todd, P. Denys, C. Pearson, C. Sangster, J. Garcia-Mayordomo, T. Goded, E. Abbott, C. Ohneiser, P. Lepine, and F. Caratori-Tontini


Natural Hazards Research Platform Contes 2015, Report published 2018 by GNS Science.

Key Questions and Motivation:

  • Could a similar earthquake sequence to the September 4, 2010 Darfield sequence occur in Dunedin City? Dunedin has a similar built environment to the one Christchurch had prior to 2010, and is known to have active faults nearby (the Akatore and Titri Faults). In this project we assessed whether these faults, or other active faults, could extend into the city.

  • Various lines of evidence indicate that the Akatore Fault does not extend into Dunedin City. We also discovered that the Titri Fault extends northwards and closer to the city than previously mapped, but it but it has buckled rather than broken the ground surface there.

  • A newly mapped and possibly active fault, the Kaikorai Fault, lies in the western part of the city. It is thought that this newly mapped fault would likely rupture together with the offshore Green Island Fault.


Histograms showing number of weekly (top) tremor detections and (bottom) earthquakes with the cumulative counts plotted in red between 2010 and 2015

Tectonic tremor along the northern Hikurangi Margin, New Zealand, between 2010 and 2015


Erin K. Todd and Susan Schwartz

Year, Journal:

2016, Journal of Geophysical Research Letters - Solid Earth

Key Points:

  • Tectonic tremor associated with shallow offshore slow slip events along northern Hikurangi Margin

  • Tremor catalog for 2010 through 2015

  • Spatiotemporal relationship between slow slip, tremor, and earthquakes


Source model for the 6 July 2011 normal‐faulting event, including the focal mechanism strike (ϕ), dip (δ) and average rake (λ), rupture velocity (Vr), seismic moment (Mo), source time function, and model slip distribution.

The 2011 Northern Kermadec earthquake doublet and subduction zone faulting interactions


Erin K. Todd and Thorne Lay

Year, Journal:

2013, Journal of Geophysical Research Letters - Solid Earth

Key Points:

  • A large outer trench slope intraslab earthquake doublet (6 July 2011, Mw 7.6; 21 October 2011, Mw 7.4) occurred seaward of an interseismically-coupled region of the megathrust

  • The differing focal mechanisms (6 July: shallow normal faulting intraplate earthquake; 21 October deeper thrust faulting intraplate event) suggests the presence of a neutral bending plane in the subducting plate as it enters the Kermadec Trench

  • Both earthquakes were followed by intraslab and interplate aftershocks that suggest a static stress transfer between the outer trench slope and the shallow megathrust.