Due to a problem during a software upgrade, the text formatting and SVG image display are broken broken in posts that are generated as Jupyter notebooks. I hope to fix this soon, but in the mean time, my apologies.

This text is slightly adapted from a lecture I gave at Oxford in June 2022.

In PSHA, we are seeking to characterize the behavior of a system. In regional PSHA, we are looking at a system of seismic sources (typically faults and background sources), as well as a heterogeneous lithosphere and its irregular surface, where we want to calculate the effect of seismic waves generated by the sources. For a site-specific or scenario-based analysis, we are cutting down on the dimensionality of the problem in some capacity but we may be adding more depth or complexity of analysis for whatever parts of the system that we are analyzing.

The different components of the system are interactive, and to do the best job possible we have to be able to describe each component and understand how it interacts with other components. Working in this manner is different than considering the components in isolation, as is often done, but this presents opportunities in addition to challenges, because we can use system-level constraints such as budgets to reduce uncertainties and to make inferences where measurements are difficult or otherwise lacking.

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I use conda extensively to manage Python environments. While I have my frustrations with it, in particular the slow and brittle dependency solver, it services my needs rather well.

However, no one else at GEM uses it, so it's not supported as an environment …

I am slowly putting together a high-resolution joint geodetic-geologic block model as a way of estimating fault slip rates for all faults in a revamped GEM Global Active Fault Database. As of this writing, I have much of North America and the Tethyan belt of Asia drafted, and showing various …

This is the presentation I gave at the Seismological Society of America meeting this spring. It highlights ongoing work on incorporating block modeling into seismic hazard analysis.

Authors: Richard Styron, Tiegan Hobbs, Nick Harrichhausen, Murray Journeay

Abstract

The western margin of North America in the Cascadia region is known to …

I've spent quite a bit of time over the last year drawing blocks (microplates) that are partially bounded by faults, to make block models that I can use to invert geodetic velocities and geologic slip rate data to get internally-consistent slip rates for all faults in a deforming region.

One …

In a previous post, I showed a movie of Tibetan blocks motions from an inversion of geodetic and geologic data. The movie is informative, but as I have developed the inversion, I have relied on GPlates to be able to view the motions interactively, i.e. by panning and zooming …

I've spent quite a bit of time this year working on characterizing the fault network for China and the vicinity (Himalaya, Tien Shan and the northwestern Pamir). This has involved remapping HimaTibetMap and writing a new block modeling program to solve for internally-consistent slip rates on all the faults in …

A guest post by the Figure Master Lydia Staisch

Here is a map! It's LiDAR and scaled to a poster size of 45"x30" -- it has the potential to be an absolutely monstrous file size when exported.