A Seismologically Consistent Surface Rupture Length Model for Unbounded and Width-Limited Event

A new surface-rupture-length ($SRL$) relationship as a function of magnitude ($\mathbf{M}$), fault thickness, and fault dip angle is presented in this paper. The objective of this study is to model the change in scaling between unbounded and width-limited ruptures. This is achieved through the use of seismological-theory-based relationships for the average displacement scaling and the aid of dynamic fault rupture simulations to constrain the rupture width scaling. The empirical dataset used in the development of this relationship is composed of $123$ events ranging from $\mathbf{M}~5$ to $8.1$ and $SRL~1.1$ to $432~km$. The dynamic rupture simulations dataset includes $554$ events ranging from $\mathbf{M}~4.9$ to $8.2$ and $SRL~1$ to $655~km$. For the average displacement ($\bar{D}$) scaling, three simple models and two composite models were evaluated. The simple average displacement models were: a square root of the rupture area ($\sqrt{A}$), a down-dip width ($W$), and a rupture length ($L$) proportional model. The two composite models followed a $\sqrt{A}$ scaling for unbounded ruptures and transitioned to $W$ and $L$ scaling for width-limited events, respectively. The empirical data favors a $\bar{D} \sim \sqrt{A}$ scaling for both unbounded and width-limited ruptures. The proposed model exhibits better predictive performance compared to linear $\log(SLR)\sim\mathbf{M}$ type models, especially in the large magnitude range, which is dominated by width-limited events. A comparison with existing $SRL$ models shows consistent scaling at different magnitude ranges that is believed to be the result of the different magnitude ranges in the empirical dataset of the published relationships.Comment: 21 pages, 11 figure

Selection of ground motion prediction equations for the global earthquake model

Ground motion prediction equations (GMPEs) relate ground motion intensity measures to variables describing earthquake source, path, and site effects. From many available GMPEs, we select those models recommended for use in seismic hazard assessments in the Global Earthquake Model. We present a GMPE selection procedure that evaluates multidimensional ground motion trends (e.g., with respect to magnitude, distance, and structural period), examines functional forms, and evaluates published quantitative tests of GMPE performance against independent data. Our recommendations include: four models, based principally on simulations, for stable continental regions; three empirical models for interface and in-slab subduction zone events; and three empirical models for active shallow crustal regions. To approximately incorporate epistemic uncertainties, the selection process accounts for alternate representations of key GMPE attributes, such as the rate of distance attenuation, which are defensible from available data. Recommended models for each domain will change over time as additional GMPEs are developed

Next-Generation Liquefaction (NGL) Case History Database Structure

This paper presents the organizational structure (schema) of the Next-Generation Liquefaction (NGL) relational database. The schema describes the tables, fields, and relationships among the tables, and provides an important resource for users who wish to interact with the database by writing queries. Structured relational databases are not commonly utilized in the natural hazards community, where file repositories are more commonly used and often called "databases". This paper also discusses what a relational database is, and why this approach was adopted for the NGL project

Next-Generation Liquefaction (NGL) Case History Database Structure

This paper presents the organizational structure (schema) of the Next-Generation Liquefaction (NGL) relational database. The schema describes the tables, fields, and relationships among the tables, and provides an important resource for users who wish to interact with the database by writing queries. Structured relational databases are not commonly utilized in the natural hazards community, where file repositories are more commonly used and often called "databases". This paper also discusses what a relational database is, and why this approach was adopted for the NGL project

Comparison of ground motion attributes from 2011 Tohoku-oki mainshock and two subsequent events

The Mw 9.0 Tohoku-oki Japan earthquake and many of its subsequent aftershocks and triggered events were very well recorded, providing opportunity for detailed study of source, path, and site effects. In previous work, we utilized mainshock data to demonstrate faster attenuation with distance in backarc than in forearc regions, positive event terms for high frequency intensity measures for multiple ground motion prediction models, and minimal scaling of site amplification with Vs30 at high frequencies. In this paper, we consider two subsequent events, one Mw 6.7 on the plate interface that ruptured in the mainshock and one Mw 6.3 inland from the volcanic front, to examine if similar ground motion features are apparent from these data sets. We continue to find evidence for the divergence in attenuation rate in forearc and backarc regions, despite the fact that the events are located on opposite sides of the volcanic front. The site response for these events does not appear to follow previously observed patterns for Japan, being relatively similar to Vs30-scaling in active crustal regions generally.&nbsp