Ground Motion in the Presence of Complex Topography: Earthquake and Ambient Noise Sources

Hartzell, Stephen H.; Meremonte, Mark; Ramirez-Guzmán, L.; McNamara, Daniel E.

doi:10.1785/0120130088

Cited by 48 publications

(24 citation statements)

References 48 publications

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“…Thus, we estimate that the low-frequency amplification, likely to be influenced by the general hill topography as explained in the previous section, is not reproduced at all by the ambient vibration HVSR; only some weak resonance effects can be observed for the higher frequency range that was attributed above to surface layer amplification. A similar observation was made by [19], who noted that SSR presents the clearest low-frequency peak for earthquakes recorded along a ridge in the San Francisco Bay area (in their case near 1 Hz). They interpreted this peak as the fundamental one related to topographic amplification.…”

Section: The Use Of Hvsr For Site Effect Analysissupporting

confidence: 81%

Site Effect Assessment of the Gros-Morne Hill Area in Port-au-Prince, Haiti, Part B: Mapping and Modelling Results

Ulysse

Boisson

Prépetit³

et al. 2018

Geosciences

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This paper presents the general results in terms of maps, as well as geological and numerical models of a site effect study, that aimed at a better understanding of the ground motion amplification on the Gros-Morne hill, in the southeastern part of Port-au-Prince, Haiti, which might have influenced the 2010 event damage pattern in that area. These maps and models are based on multiple geophysical-seismological survey outputs that are presented, in detail, in Part A of this publication. Those outputs include electrical resistivity tomography sections, P-wave velocity profiles, S-wave logs, estimates of the fundamental resonance frequency for many locations, as well as earthquake recordings at three sites and associated site amplification assessment for the top of the hill. Related results are discussed in Part A with respect to outputs and interpretations that had been published earlier by other research teams for the same site. Our results only partly confirm the strong seismic amplification effects highlighted by some of the previous studies for this hill site, which had been attributed to the influence of local topographic and soil characteristics on seismic ground motion. Here, we focus on the imaging of different site effect components over the entire survey area; we present maps of shear wave velocity variations, of changing fundamental resonance frequencies, and of related estimates of soft soil/rock thickness, of peak spectral amplitudes, and of ambient ground motion polarization. Results have also been compiled within a 3D surface-subsurface model of the hill, which helps visualize the geological characteristics of the area, which are relevant for site effect analyses. From the 3D geomodel, we extracted one 2D geological section along the short-axis of the hill, crossing it near the location of Hotel Montana on top of the hill, which had been destroyed during the earthquake, and has now been rebuilt. This cross-section was used for dynamic numerical modelling of seismic ground motion, and for related site amplification calculation. The numerical results are compared with the site amplification characteristics that had been estimated from the ambient vibration measurements and the earthquake recordings.

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Section: The Use Of Hvsr For Site Effect Analysissupporting

confidence: 81%

Site Effect Assessment of the Gros-Morne Hill Area in Port-au-Prince, Haiti, Part B: Mapping and Modelling Results

Ulysse

Boisson

Prépetit³

et al. 2018

Geosciences

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“…Boore, 1973;Massa et al, 2014;Poursartip et al, 2017). Both seismic noise analysis and strong motion records confirm that stronger shaking often occurs at topographic highs (Chávez-García et al, 1996;Durante et al, 2017;Hartzell et al, 2014;Massa et al, 2010). Meunier et al (2008) suggested that earthquakeinduced landslides tend to cluster around ridge crests as a consequence of these topographic site effects.…”

Section: Introductionmentioning

confidence: 93%

Seismic and geologic controls on spatial clustering of landslides in three large earthquakes

Rault¹,

Robert

Marc

et al. 2019

Earth Surf. Dynam.

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The large, shallow earthquakes at Northridge, California (1994), Chi-Chi, Taiwan (1999), and Wenchuan, China (2008), each triggered thousands of landslides. We have determined the position of these landslides along hillslopes, normalizing for statistical bias. The landslide patterns have a co-seismic signature, with clustering at ridge crests and slope toes. A cross-check against rainfall-induced landslide inventories seems to confirm that crest clustering is specific to seismic triggering as observed in previous studies. In our three study areas, the seismic ground motion parameters and lithologic and topographic features used do not seem to exert a primary control on the observed patterns of landslide clustering. However, we show that at the scale of the epicentral area, crest and toe clustering occur in areas with specific geological features. Toe clustering of seismically induced landslides tends to occur along regional major faults. Crest clustering is concentrated at sites where the lithology along hillslopes is approximately uniform, or made of alternating soft and hard strata, and without strong overprint of geological structures. Although earthquake-induced landslides locate higher on hillslopes in a statistically significant way, geological features strongly modulate the landslide position along the hillslopes. As a result the observation of landslide clustering on topographic ridges cannot be used as a definite indicator of the topographic amplification of ground shaking.

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“…In this case, slopes adjacent to the active fault, where the largest earthquake effects are expected, are unlikely to have DSGSD scarps because they are principally features on and around ridges rather than on lower slopes near valleys (Figure a). In addition, many studies suggest that dynamic ground motion is amplified on ridges (e.g., Geli et al, ; Hartzell et al, ), whereas static crustal strain generally is smaller under a mountain because it represents additional elastic material that resists deformation (e.g., Segall, ; Williams & Wadge, ). However, these complex effects are not taken into account in our calculation.…”

Section: Analysesmentioning

confidence: 99%

Discovery, Controls, and Hazards of Widespread Deep‐Seated Gravitational Slope Deformation in the Etsumi Mountains, Central Japan

Kaneda

Kono

2017

JGR Earth Surface

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Deep‐seated gravitational slope deformation (DSGSD) is a largely unnoticed but important long‐term mass wasting process that may result in catastrophic failure of mountain slopes. Manifested by small topographic irregularities such as ridge‐parallel scarps and linear depressions, it has been predominantly reported in alpine landscapes above timber lines. On the basis of area‐wide high‐resolution topographic data acquired by light detection and ranging (lidar) surveys, we here show that ~96% of existing gravitational scarps have been hidden under forest canopies in the Etsumi Mountains, central Japan. The scarps are surprisingly widespread over the mountains with a mean line density of as large as 0.87 km/km2. Our analyses of the scarp distribution suggest that uphill‐facing scarps are primary geomorphic signals of DSGSD with a destabilized rock mass larger than ~105 m2, whereas downhill‐facing scarps principally occur in response to more localized slope deformation. In terms of controls, topography is by far the most influential factor in triggering and promoting DSGSD. Despite the M 7.5 earthquake in 1891, impact of large local earthquakes proves to be not very strong. Comparison with preexisting landslide maps further suggests that DSGSD and large‐scale landslides are not different slope processes but represent different stages of the same process. Our results highlight limitations of aerial‐photograph interpretation in forest‐covered mountains and the need for lidar‐assisted mapping for deeper understanding of this long‐term process and interactions between surface and tectonic processes.

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Ground Motion in the Presence of Complex Topography: Earthquake and Ambient Noise Sources

Cited by 48 publications

References 48 publications

Site Effect Assessment of the Gros-Morne Hill Area in Port-au-Prince, Haiti, Part B: Mapping and Modelling Results

Site Effect Assessment of the Gros-Morne Hill Area in Port-au-Prince, Haiti, Part B: Mapping and Modelling Results

Seismic and geologic controls on spatial clustering of landslides in three large earthquakes

Discovery, Controls, and Hazards of Widespread Deep‐Seated Gravitational Slope Deformation in the Etsumi Mountains, Central Japan

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