Precarious Rocks

Anderson, John G.; Biasi, Glenn P.; Brune, James N.

doi:10.1016/b978-0-12-394848-9.00014-6

Cited by 9 publications

(6 citation statements)

References 34 publications

(38 reference statements)

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“…12b and d. These findings are consistent with the previous reports on rectangle experiments on a 2D plane (Purvance et al, 2008;Anderson et al, 2014;Yim et al, 1980). The cuboids with 1×1×3 meters and 1×2×3 meters had similar overturning response diagrams except for a small number of noises (Fig.…”

Section: Cuboids Overturning On Flat Terrainsupporting

confidence: 93%

“…Seismologists have studied the overturning responses of PBRs from ground motions for seismic hazard analysis (Housner, 1963;Brune, 1996;Shi et al, 1996;Anooshehpoor et al, 2004;Rood et al, 2020Rood et al, , 2022. PBR fragility provides an upper bound on the strength of the ground motions in the time interval since the PBRs became frag-ile (Brune et al, 2006;Anderson et al, 2014). In southern California, most PBRs have been fragile for thousands of years or longer (Brune et al, 2006;Rood et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

“…Seismic hazard analysis typically considers the PBR overturning responses, which are immediate binary results (balanced or overturned, Anderson et al, 2014). However, their motions after overturning are complex and informative.…”

Section: Introductionmentioning

confidence: 99%

“…The large displacements of these rocks contribute to understanding the fate of PBRs and the development of rocky slopes. Additionally, many discovered PBRs present rockfall hazards (Anderson et al, 2014). As a serious natural hazard, rockfall poses a major threat to infrastructure, transportation lines, and people (Dorren, 2003;Leine et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…The dynamics of PBRs for seismic hazard analysis are aimed to model an overturning process, which is a mapping from ground motions to PBR response of overturned or not. Ground motions are characterized by intensity measures (Anderson et al, 2014;Purvance et al, 2008), such as peak ground acceleration (PGA), peak ground velocity (PGV), peak ground displacement, SA(1Hz), and SA(2 Hz), where SA(n Hz) Figure 1 Workflow of using precariously balanced rocks (PBRs) for seismic hazard analysis, PBR fate, rocky slope development, and rockfall prediction. PBR dynamics involve overturning process and large-displacement process.…”

Section: Introductionmentioning

confidence: 99%

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Virtual Shake Robot: Simulating Dynamics of Precariously Balanced Rocks for Overturning and Large-displacement Processes

Chen,

Arrowsmith,

Das

et al. 2024

Seismica

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Understanding the dynamics of precariously balanced rocks (PBRs) is important for seismic hazard analysis and rockfall prediction. Utilizing a physics engine and robotic tools, we develop a virtual shake robot (VSR) to simulate the dynamics of PBRs during overturning and large-displacement processes. We present the background of physics engines and technical details of the VSR, including software architecture, mechanical structure, control system, and implementation procedures. Validation experiments show the median fragility contour from VSR simulation is within the 95% prediction intervals from previous physical experiments, when PGV/PGA is greater than 0.08 s. Using a physical mini shake robot, we validate the qualitative consistency of fragility anisotropy between the VSR and physical experiments. By overturning cuboids on flat terrain, the VSR reveals the relationship between fragility and geometric dimensions (e.g., aspect and scaling ratios). The ground motion orientation and lateral pedestal support affect PBR fragility. Large-displacement experiments estimate rock trajectories for different ground motions, which is useful for understanding the fate of toppled PBRs. Ground motions positively correlate with large displacement statistics such as mean trajectory length, mean largest velocity, and mean terminal distance. The overturning and large displacement processes of PBRs provide complementary methods of ground motion estimation.

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Section: Cuboids Overturning On Flat Terrainsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Virtual Shake Robot: Simulating Dynamics of Precariously Balanced Rocks for Overturning and Large-displacement Processes

Chen,

Arrowsmith,

Das

et al. 2024

Seismica

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Integrating rock pillars into a fragile geologic features analysis of fault activity in the Negev, Israel

Finzi¹,

Ganz²,

Dor³

et al. 2020

Preprint

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Stability Analysis of Fragile Rock Pillars and Insights on Fault Activity in the Negev, Israel

Finzi

Ganz

Dor³

et al. 2020

JGR Solid Earth

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Fragile geologic features (FGFs) are used as negative indicators of strong ground motion. By evaluating the stability of FGFs and determining their age, it is possible to constrain the local maximum seismic ground acceleration that has occurred during their lifetime. This methodology was originally developed to analyze precariously balanced rocks (a subset of FGFs) and has been used to assess long-term fault activity and improve seismic hazard analyses. In the Negev desert of Israel, several in situ, slender rock pillars exhibit natural frequencies within the range of seismic waves (1-10 Hz) and therefore constitute an important FGF subset. However, the motion of such pillars may be complex with an initial stage of swaying followed by basal detachment, rocking and toppling, or failure within the pillar. To demonstrate that pillar stability can be analyzed using the existing FGF methodology, we show that the tensional stresses developed at the base of a pillar swaying at its fundamental modes of motion are comparable or larger than the typical tensile strength of Negev pillars. Finally, we demonstrate how a newly documented data set of Negev FGFs can be used to provide new insights on fault activity along the Negev-Sinai Shear Zone and the Arava Fault. Assuming a plausible range of motion amplification, the stability analysis of long-standing FGFs yields significant constraints on fault seismicity parameters (M max < 7 for a section of the Arava Fault). Extending the regional data set would provide important insights for regional seismic hazard along the Dead Sea Transform.

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Precarious Rocks

Cited by 9 publications

References 34 publications

Virtual Shake Robot: Simulating Dynamics of Precariously Balanced Rocks for Overturning and Large-displacement Processes

Virtual Shake Robot: Simulating Dynamics of Precariously Balanced Rocks for Overturning and Large-displacement Processes

Integrating rock pillars into a fragile geologic features analysis of fault activity in the Negev, Israel

Stability Analysis of Fragile Rock Pillars and Insights on Fault Activity in the Negev, Israel

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