TY  - JOUR
A1  - Mohr, Christian Heinrich
A1  - Manga, Michael
A1  - Wald, David
T1  - Stronger peak ground motion, beyond the threshold to initiate a response, does not lead to larger stream discharge responses to earthquakes
JF  - Geophysical research letters
N2  - The impressive number of stream gauges in Chile, combined with a suite of past and recent large earthquakes, makes Chile a unique natural laboratory to study several streams that recorded responses to multiple seismic events. We document changes in discharge in eight streams in Chile following two or more large earthquakes. In all cases, discharge increases. Changes in discharge occur for peak ground velocities greater than about 7-11cm/s. Above that threshold, the magnitude of both the increase in discharge and the total excess water do not increase with increasing peak ground velocities. While these observations are consistent with previous work in California, they conflict with lab experiments that show that the magnitude of permeability changes increases with increasing amplitude of ground motion. Instead, our study suggests that streamflow responses are binary. Plain Language Summary Earthquakes deform and shake the surface and the ground below. These changes may affect groundwater flows by increasing the permeability along newly formed cracks and/or clearing clogged pores. As a result, groundwater flow may substantially increase after earthquakes and remain elevated for several months. Here we document streamflow anomalies following multiple high magnitude earthquakes in multiple streams in one of the most earthquake prone regions worldwide, Chile. We take advantage of the dense monitoring network in Chile that recorded streamflow since the 1940s. We show that once a critical ground motion is exceeded, streamflow responses to earthquakes can be expected.
KW  - earthquake
KW  - streamflow
KW  - shaking
KW  - Chile
KW  - modeling
Y1  - 2018
U6  - https://doi.org/10.1029/2018GL078621
SN  - 0094-8276
SN  - 1944-8007
VL  - 45
IS  - 13
SP  - 6523
EP  - 6531
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Oeser, Ralf Andreas
A1  - Stroncik, Nicole
A1  - Moskwa, Lisa-Marie
A1  - Bernhard, Nadine
A1  - Schaller, Mirjam
A1  - Canessa, Rafaella
A1  - van den Brink, Liesbeth
A1  - Köster, Moritz
A1  - Brucker, Emanuel
A1  - Stock, Svenja
A1  - Pablo Fuentes, Juan
A1  - Godoy, Roberto
A1  - Javier Matus, Francisco
A1  - Oses Pedraza, Romulo
A1  - Osses McIntyre, Pablo
A1  - Paulino, Leandro
A1  - Seguel, Oscar
A1  - Bader, Maaike Y.
A1  - Boy, Jens
A1  - Dippold, Michaela A.
A1  - Ehlers, Todd
A1  - Kühn, Peter
A1  - Kuzyakov, Yakov
A1  - Leinweber, Peter
A1  - Scholten, Thomas
A1  - Spielvogel, Sandra
A1  - Spohn, Marie
A1  - Ubernickel, Kirstin
A1  - Tielbörger, Katja
A1  - Wagner, Dirk
A1  - von Blanckenburg, Friedhelm
T1  - Chemistry and microbiology of the Critical Zone along a steep climate and vegetation gradient in the Chilean Coastal Cordillera
JF  - Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution
N2  - From north to south, denudation rates from cosmogenic nuclides are similar to 10 t km(-2) yr(-1) at the arid Pan de Aziicar site, similar to 20 t km(2) yr(-1) at the semi-arid site of Santa Gracia, -60 t km(-2) yr(-1) at the Mediterranean climate site of La Campana, and similar to 30 t km(-2) yr(-1) at the humid site of Nahuelbuta. A and B horizons increase in thickness and elemental depletion or enrichment increases from north (similar to 26 degrees S) to south (similar to 38 degrees S) in these horizons. Differences in the degree of chemical weathering, quantified by the chemical depletion fraction (CDF), are significant only between the arid and sparsely vegetated site and the other three sites. Differences in the CDF between the sites, and elemental depletion within the sites are sometimes smaller than the variations induced by the bedrock heterogeneity. Microbial abundances (bacteria and archaea) in saprolite substantially increase from the arid to the semi-arid sites. With this study, we provide a comprehensive dataset characterizing the Critical Zone geochemistry in the Chilean Coastal Cordillera. This dataset confirms climatic controls on weathering and denudation rates and provides prerequisites to quantify the role of biota in future studies.
KW  - Weathering
KW  - Denudation
KW  - Microbial abundance
KW  - Climate
KW  - Chile
Y1  - 2018
U6  - https://doi.org/10.1016/j.catena.2018.06.002
SN  - 0341-8162
SN  - 1872-6887
VL  - 170
SP  - 183
EP  - 203
PB  - Elsevier
CY  - Amsterdam
ER  -