Expert Judgement for Geological Hazards in New Zealand

Christophersen, Annemarie; Gerstenberger, Matthew C.

doi:10.1007/978-3-030-46474-5_15

Cited by 4 publications

(1 citation statement)

References 42 publications

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“…Then, however, the significant impact on the power balance would be tightly controlled by the expert's decision of the incompatible anomaly magnitude, which hence has to be an unanimous conclusion. To take into account more gradual information, such as considering an anomaly to be unlikely but possible, is complex to formalize to a quantitative scale and might require the judgment of multiple experts (see e.g., Christophersen & Gerstenberger, 2021).…”

Section: Theorymentioning

confidence: 99%

Revisiting the San Andreas Heat Flow Paradox From the Perspective of Seismic Efficiency and Elastic Power in Southern California

Ziebarth,

Anderson,

von Specht

et al. 2023

JGR Solid Earth

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We investigate the relation between frictional heating on a fault and the resulting conductive surface heat flow anomaly using the fault's long‐term energy budget. Analysis of the surface heat flow surrounding the fault trace leads to a constraint on the frictional power generated on the fault—the mechanism behind the San Andreas fault (SAF) heat flow paradox. We revisit this paradox from a new perspective using an estimate of the long‐term accumulating elastic power in the region surrounding the fault, and analyze the paradox using two parameters: the seismic efficiency and the elastic power. The results show that the constraint on frictional power from the classic interpretation is incompatible with the accumulating elastic power and the radiated power from earthquake catalogs. We then explore four mechanisms that can resolve this extended paradox. First, stochastic fluctuations of surface heat flow could mask the fault‐generated anomaly (we estimate 21% probability). Second, the elastic power accumulating in the region could be overestimated (≥550 MW required). Third, the seismic efficiency—ratio of radiated energy to elastic work—of the SAF could be higher than that of the remaining faults in the region (≥5.8% required). Fourth, the scaled energy—ratio of radiated energy to seismic moment—on the SAF could be lower than on the remaining faults in the region (a factor 5 difference required). In the last three hypotheses, we analyze the interplay of the energy budget on a single fault with the total energy budget of the region.

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Section: Theorymentioning

confidence: 99%

Revisiting the San Andreas Heat Flow Paradox From the Perspective of Seismic Efficiency and Elastic Power in Southern California

Ziebarth,

Anderson,

von Specht

et al. 2023

JGR Solid Earth

View full text Add to dashboard Cite

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The 2022 Aotearoa New Zealand National Seismic Hazard Model: Process, Overview, and Results

Gerstenberger,

Bora,

Bradley

et al. 2023

Bulletin of the Seismological Society of America

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The 2022 revision of Aotearoa New Zealand National Seismic Hazard Model (NZ NSHM 2022) has involved significant revision of all datasets and model components. In this article, we present a subset of many results from the model as well as an overview of the governance, scientific, and review processes followed by the NZ NSHM team. The calculated hazard from the NZ NSHM 2022 has increased for most of New Zealand when compared with the previous models. The NZ NSHM 2022 models and results are available online.

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Expert Judgment in the 2022 Aotearoa New Zealand National Seismic Hazard Model

Christophersen,

Gerstenberger

2023

Seismological Research Letters

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The 2022 revision of the New Zealand National Seismic Hazard Model—Te Tauira Matapae Pūmate Rū i Aotearoa (NZ NSHM 2022) is, like other regional and national seismic hazard models, a collection of many component models that are combined via logic trees to calculate various parameters of seismic hazard. Developing, selecting, and combining component models for the NZ NSHM 2022 requires expert judgment. Informal and unstructured use of expert judgment can lead to biases. Drawing on a broad body of literature on potential biases in expert judgment and how to mitigate them, we used three approaches to incorporate expert judgment with the aim to minimize biases and understand uncertainty in seismic hazard results. The first approach applied two closely aligned group structures—the Science Team Working Groups and the Technical Advisory Group (TAG). The groups between them defined the project and made the scientific decisions necessary to produce the final model. Second, the TAG provided the function of a participatory review panel, in which the reviewers of the NSHM were actively engaged throughout the project. The third approach was performance-based weighting of expert assessments, which was applied to the weighting of the logic trees. It involved asking experts so-called calibration questions with known answers, which were relevant to the questions of interest, that is, the logic-tree weights. Each expert provided their best estimates with uncertainty, from which calibration and information scores were calculated. The scores were used to weight the experts’ assessments. The combined approach to incorporating expert judgment was intended to provide a robust and well-reviewed application of seismic hazard analysis for Aotearoa, New Zealand. Robust expert judgment processes are critical to any large science project, and our approach may provide learnings and insights for others.

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Expert Judgement for Geological Hazards in New Zealand

Cited by 4 publications

References 42 publications

Revisiting the San Andreas Heat Flow Paradox From the Perspective of Seismic Efficiency and Elastic Power in Southern California

Revisiting the San Andreas Heat Flow Paradox From the Perspective of Seismic Efficiency and Elastic Power in Southern California

The 2022 Aotearoa New Zealand National Seismic Hazard Model: Process, Overview, and Results

Expert Judgment in the 2022 Aotearoa New Zealand National Seismic Hazard Model

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