We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham Research Online
You are in:

Seismic mountain building : landslides associated with the 2008 Wenchuan earthquake in the context of a generalized model for earthquake volume balance.

Li, G. and West, A. J. and Densmore, A. L. and Jin, Z. and Parker, R. N. and Hilton, R. G. (2014) 'Seismic mountain building : landslides associated with the 2008 Wenchuan earthquake in the context of a generalized model for earthquake volume balance.', Geochemistry, geophysics, geosystems., 15 (4). pp. 833-844.


Here we assess earthquake volume balance and the growth of mountains in the context of a new landslide inventory for the Mw 7.9 Wenchuan earthquake in central China. Coseismic landslides were mapped from high-resolution remote imagery using an automated algorithm and manual delineation, which allow us to distinguish clustered landslides that can bias landslide volume calculations. Employing a power-law landslide area-volume relation, we find that the volume of landslide-associated mass wasting (∼2.8 + 0.9/−0.7 km3) is lower than previously estimated (∼5.7–15.2 km3) and comparable to the volume of rock uplift (∼2.6 ± 1.2 km3) during the Wenchuan earthquake. If fluvial evacuation removes landslide debris within the earthquake cycle, then the volume addition from coseismic uplift will be effectively offset by landslide erosion. If all earthquakes in the region followed this volume budget pattern, the efficient counteraction of coseismic rock uplift raises a fundamental question about how earthquakes build mountainous topography. To provide a framework for addressing this question, we explore a group of scaling relations to assess earthquake volume balance. We predict coseismic uplift volumes for thrust-fault earthquakes based on geophysical models for coseismic surface deformation and relations between fault rupture parameters and moment magnitude, Mw. By coupling this scaling relation with landslide volume-Mw scaling, we obtain an earthquake volume balance relation in terms of moment magnitude Mw, which is consistent with the revised Wenchuan landslide volumes and observations from the 1999 Chi-Chi earthquake in Taiwan. Incorporating the Gutenburg-Richter frequency-Mw relation, we use this volume balance to derive an analytical expression for crustal thickening from coseismic deformation based on an index of seismic intensity over a defined area. This model yields reasonable rates of crustal thickening from coseismic deformation (e.g., ∼0.1–0.5 km Ma−1 in tectonically active convergent settings), and implies that moderate magnitude earthquakes (Mw ≈ 6–7) are likely responsible for most of the coseismic contribution to rock uplift because of their smaller landslide-associated volume reduction. Our first-order model does not consider a range of factors (e.g., lithology, climate conditions, epicentral depth, and tectonic setting), nor does it account for viscoelastic effects or isostatic responses to erosion, and there are important large uncertainties on the scaling relationships used to quantify coseismic deformation. Nevertheless, our study provides a conceptual framework and invites more rigorous modeling of seismic mountain building.

Item Type:Article
Keywords:Wenchuan earthquake, Earthquake, Volume balance, Seismic mountain building, Landslide.
Full text:(VoR) Version of Record
Download PDF (Advance online version)
Publisher Web site:
Publisher statement:© 2014. American Geophysical Union
Date accepted:14 January 2014
Date deposited:30 April 2014
Date of first online publication:11 April 2014
Date first made open access:No date available

Save or Share this output

Look up in GoogleScholar