Revisiting the 1959 Hebgen Lake Earthquake Using Optical Image Correlation; New Constraints on Near‐Field 3D Ground Displacement

Abstract

The Hebgen Lake earthquake occurred on the 18th August (GMT) 1959 in SW Montana, U.S. This region lies within a zone of slow intracontinental extension, at the intersection between the Yellowstone volcanic system and the Intermountain Seismic Belt (Chang et al., 2013;Smith & Sbar, 1974). The Hebgen Lake earthquake was preceded by at least two events with similar magnitude that were dated at 1-3 and 10-14.5 ka by cosmogenic nuclide geochronology (Schwartz et al., 2009;Zreda & Noller, 1998). The 1959 event consisted of two sub-events with magnitude 7.0 and 6.3, separated by a 5-s time interval, and was followed by large aftershocks on the 18th and 19th of August (Doser, 1985). The subsidence associated with the Hebgen Lake earthquake was recorded over a broad area of approximately 1,500 km 2 , and more than 150 km 2 subsided by more than 3.1 m (Myers & Hamilton, 1964).The earthquake produced structurally complex surface ruptures with notable displacements along the Hebgen fault (HF), the Red Canyon fault (RCF), the Kirkwood fault (KF), and the West Fork fault (WFF). These are west-dipping normal faults with a cumulative length of approximately 35.4 km and maximum vertical offsets of 6.1, 5.8, 0.6, and 1.2 m, respectively (Figure 1, Witkind et al., 1962). Despite some geometric complexity, the ruptures generally strike 130° ± 10°, consistent with the fault plane solution from the main shock (Barrientos et al., 1989;Doser, 1985), and dip SW by 50°-85° (Witkind, 1964). Doser (1985) and Ryall (1962) locate the epicenter 15 km northeast of Hebgen Lake, with a depth of approximately 15-25 km. However, uncertainty in the location, and especially the depth of the hypocenter makes it difficult to assess the spatial relationship between the source and the surface ruptures (Doser, 1985).

Impact of optical imagery and topography data resolution on the measurement of surface fault displacement using sub-pixel image correlation

“…2, steps 6 and 7). A wide range correlation parameters (e.g., Cofaru et al, 2010;Rosu et al, 2015) and filtering techniques (e.g., Andreuttiova et al, 2022;Stumpf et al, 2018) can be used to improve the OIC result for each dataset. However, the combined effects of these techniques and parametrizations are numerous, can vary for each dataset, and are thus not directly addressed within the scope of this study which primarily focuses on the effect of the data resolution.…”

3D Coseismic Surface Displacements From Historical Aerial Photographs of the 1987 Edgecumbe Earthquake, New Zealand

“…Post-event aerial photos have been supplemented with inferred pre-earthquake topography to reduce noise and measure displacements (Lajoie et al, 2020). Andreuttiova et al (2022) used legacy aerial photos to measure 3D surface displacements for a large (M w 7.0 mainshock) event by combining two techniques: optical image correlation for horizontal displacements and subtracting pre-and post-earthquake DSMs for vertical displacements.…”

“…Andreuttiova et al. (2022) used legacy aerial photos to measure 3D surface displacements for a large ( M w 7.0 mainshock) event by combining two techniques: optical image correlation for horizontal displacements and subtracting pre‐ and post‐earthquake DSMs for vertical displacements.…”

“…Historical and modern aerial photographs occupy a useful niche for studying earthquakes because they span long periods of time (70+ years), often with repeat surveys. With more recent advances in photogrammetry techniques, existing aerial photographs can be used to generate additional pre‐ and post‐earthquake topographic data to supplement lidar, satellite, and field‐based data (e.g., Andreuttiova et al., 2022; Howell et al., 2020; Zhou et al., 2016). This means that high‐resolution 2D and 3D displacement fields, typically only achievable for recent ruptures with modern techniques like differential lidar or InSAR, can theoretically be produced for any earthquake where sufficient‐quality pre‐ and post‐event photos are available.…”

“…A number of techniques exist to measure single‐event coseismic deformation and resolve slip from optical and lidar datasets, including 3D point cloud differencing (iterative closest point, or ICP, algorithm; after Nissen et al., 2012), pixel‐tracking (e.g., Barnhart et al., 2020; Leprince et al., 2007; Milliner et al., 2015; Scott et al., 2018), and basic DSM differencing and manual feature‐tracking for vertical and horizontal displacements, respectively. These multi‐temporal data remove ambiguity in correlating cumulative displacements to individual earthquakes, which can be particularly important when characterizing off‐fault deformation and the role of small‐offset or secondary structures in the earthquake rupture process (Andreuttiova et al., 2022; Duffy et al., 2013; Oskin et al., 2012; Wedmore et al., 2019). Together with seismic observations, coseismic slip distributions can also reveal the influence of extrinsic (e.g., volcanic) processes on fault rupture (e.g., Scott et al., 2019; Yagi et al., 2016).…”