Field Areas

The Susquehanna Shale Hills Critical Zone Observatory is comprised of one first-order catchment in the Susquehanna River basin. This catchment, known as Shale Hills, is about 8 hectares in total area. The stream that defines the Shale Hills catchment flows into Shavers Creek in the Juniata River sub-basin. At this site, we emphasize quantitative prediction of Critical Zone evolution and structure, focusing on developing understanding of pathways and fluxes of water, solutes, and sediments. We particularly emphasize regolith structure and evolution including all relevant geochemical, hydrological, biological, and geomorphological processes operating in this temperate, forested landscape.

DEM image of Shale Hills catchment and outline of the greater Shavers Creek Watershed.  The red dot indicates the location and size of Shale Hills catchment with respect to the larger drainage basin.

Susquehanna Shale Hills Critical Zone Observatory

0.08 km2, 256-310 m elevation, 9.5 °C, 1050 mm/yr

Our interdisciplinary team works collaboratively in one observatory to advance methods for characterizing regolith, to provide a theoretical basis for predicting the distribution and properties of regolith, and to theoretically and experimentally study the impacts of regolith on fluid pathways, flow rates, and residence times.

Garner Run - Sandstone Forested


Shale Transect

7-24 °C, 1000-2500 mm/yr

Sites with constant parent lithology (Silurian Rose Hill Formation) used to study the effects of climate on regolith formation, soil geochemistry, formation and erosion. The sites are operated in collaboration between Penn State and six partner institutions.

Wales, UK

7.2 °C, 2500 mm/yr

Colgate University NY

8.3 °C, 1000 mm/yr

Juniata College PA

10 °C, 1070 mm/yr

Washington and Lee VA

13 °C, 1400 mm/yr

Univ of Tennessee TN

14.2 °C, 1220 mm/yr

Alabama A&M AL

15.6 °C, 1370 mm/yr

U of Puerto Rico - Mayaguez

24.4 °C, 2100 mm/yr


Our interdisciplinary team works collaboratively in one observatory to advance methods for characterizing regolith, to provide a theoretical basis for predicting the distribution and properties of regolith, and to theoretically and experimentally study the impacts of regolith on fluid pathways, flow rates, and residence times. 

The SSHO exists in a humid continental climate. Temperatures average 9.5°C with large seasonal differences: January temperature is –5.4°C, July is 19.0°C. The highest temperature recorded is 33.5°C (April 27, 2009) lowest –24.8°C (January 17, 2009). Annual average relative humidity is 70.2%. Atmospheric deposition in PA is still characterized by acidic (pH~4) precipitation. Water balance calculations for the last two years: 

Water balance calculations for the calendar years 2009 and 2010.

Water balance calculations for the calendar years 2009 and 2010.