Recovering paleoearthquake slip record in a highly dynamic alluvial and tectonic region (Hope Fault, New Zealand) from airborne lidar

Abstract

Knowing the slip amplitudes that large earthquakes produced in prehistorical times is one key to anticipate the magnitude of large forthcoming events. It is long known that the morphology is preserving remnants of paleoearthquake slips in the form of fault-offset landforms. However, the measured offsets that can be attributed to the most recent paleoearthquakes are generally few along a fault, so that they rarely allow recovering the slip distributions and largest slips of these earthquakes. We acquired~1 m resolution airborne lidar data on a 30 km stretch of a fast-slipping strike-slip fault (eastern Hope Fault, New Zealand) located in a region of high alluvial dynamics where landforms are rapidly evolving. Data analysis reveals >200 offset landforms; only 30% allow a good to moderate quality offset measurement. From these good to moderate quality measures, we recover the slip-length distributions and largest slips of the four most recent large paleoearthquakes and find evidence of 4-6 prior events. The record suggests that large earthquake slip recurred in multiples of about 4 m along the 30 km stretch. Although they have larger uncertainties, the more numerous lower-quality offsets that we also measured reveal a similar earthquake slip record. This shows that, although offset landforms are partly degraded in dynamically active landscapes, they store valuable information on paleoearthquake slips. This information might be recovered provided that the morphology is analyzed at high resolution and "continuously" over a significant fault length. Remote lidar data are powerful to perform such analyses.

Characteristic Slip of Strong Earthquakes Along the Yishu Fault Zone in East China Evidenced by Offset Landforms

“…COPD peaks in a fault slip distribution are valuable for distinguishing seismic events in offset data, as demonstrated by previous studies (e.g., Klinger et al, ; Manighetti et al, ; Ren et al, ; Zielke et al, ). In this study, our statistics of slip distribution show five offset probability peaks on segment S3 (Figures e and f), which occur at ~9 m, 18 m, 27 m, 35 m, and 46 m, that is, essentially multiples of ~9 m. This interval is almost consistent with the offset of the latest event in 1668 revealed by the geological survey by Cao et al (), which was approximately 7 to 9 m. Moreover, the offset density peak of 9 m possesses the largest density along all of segment S3, meaning that the landforms associated with this offset are less degraded than those associated with the other four offset density peaks.…”

“…Knowledge of the rupture history of a fault provides valuable information on the potential future behavior of the fault, enabling seismic hazard estimates and loss mitigation (Zielke et al, ). One effective method for estimating the magnitude of potential earthquakes on a fault involves analyzing past strong earthquakes that ruptured the surface and identifying measurably offset landforms preserved along the fault traces (e.g., Gold & Cowgill, ; Klinger et al, ; Manighetti et al, ; McCalpin, , ; Peltzer et al, ; Scharer et al, ; Tapponnier et al, ; Yeats & Prentice, ; Zielke et al, ). Surface slip distribution is useful in understanding the rupture history of a given fault, as demonstrated by investigations along, for example, the San Andreas fault (e.g., Zielke et al, ), Fuyun fault (e.g., Klinger et al, ) and Haiyuan fault (e.g., Ren et al, ).…”

Constraining the Distribution of Vertical Slip on the South Heli Shan Fault (Northeastern Tibet) From High‐Resolution Topographic Data

“…The occurrence of moderate to large earthquakes on a fault often leads to the offset of landforms, such as rills, small channels, alluvial fans, and other geomorphic features (Hetzel et al, ; Sieh, ; Wallace, ). Detailed mapping of these offset features and reconstruction of the slip distribution along the fault provide valuable information about the rupture history and slip accumulation pattern of the fault, based on which the future behavior of the fault can be forecast, greatly benefiting seismic hazard assessment and loss mitigation (Haddon et al, ; Klinger et al, ; Manighetti, Perrin, et al, ; Ren et al, ; Sieh, ; Wallace, ; Zielke et al, , ). Previous studies of the along‐fault slip accumulation patterns led to the formulation of now classical earthquake recurrence models, such as the characteristic earthquake model and the uniform slip model (Schwartz & Coppersmith, , ; Sieh, ; Sieh & Jahns, ), which have played key roles in seismic hazard assessment and our general understanding of fault behavior.…”

Surface Rupture Morphology and Vertical Slip Distribution of the 1959Mw7.2 Hebgen Lake (Montana) Earthquake From Airborne Lidar Topography

“…Unfortunately, we cannot obtain paleo-earthquake slip distributions for the Hebgen and Red Canyon faults in the manner that is often possible for major strike-slip faults (e.g., Haddon et al, 2016;Klinger et al, 2011;Manighetti et al, 2015;Salisbury et al, 2012;Zielke et al, 2012). Scarps formed by vertical slip are prone to rapid degradation and thus have lower preservation potential than laterally offset piercing points.…”

“…Surface ruptures are normally the only place where we can directly observe earthquake faulting. Critical aspects of the earthquake process may be expressed in its surface rupture, including source complexity (e.g., Fletcher et al, 2014;Hamling et al, 2017), rupture propagation dynamics (e.g., Elliott et al, 2009;Wesnousky, 2006), material strains (e.g., Oskin et al, 2012;Shaw, 2011), fault damage zone development (e.g., Dolan & Haravitch, 2014;Vallage et al, 2015), and slip histories over multiple earthquake cycles (e.g., Benedetti et al, 2013;Klinger et al, 2011;Manighetti et al, 2015;Salisbury et al, 2012).…”