An Incomplete Inventory of Suspected Human-Induced Surface Deformation in North America Detected by Satellite Interferometric Synthetic-Aperture Radar

Alana G Semple,Rowena B Lohman,Matthew E Pritchard

doi:10.3390/rs9121296

Abstract

We used satellite interferometric synthetic-aperture radar (InSAR) data to document ground deformation across North America suspected to be caused by human activities. We showed that anthropogenic deformation can be measured from space across the continent and thus satellite observations should be collected routinely to characterize this deformation. We included results from the literature as well as new analysis of more than 5000 interferograms from the European Remote Sensing (ERS) satellite, Envisat, the Advanced Land Observing Satellite (ALOS), and other satellites, collectively spanning the period 1992–2015. This compilation, while not complete in terms of spatial or temporal coverage nor uniform in quality over the region, contains 263 different areas of likely anthropogenic ground deformation, including 65 that were previously unreported. The sources can be attributed to groundwater extraction (50%), geothermal sites (6%), hydrocarbon production (20%), mining (21%), and other sources (3%) such as lake level changes driven by human activities and tunneling. In a few areas, the source of deformation is ambiguous. We found at least 80 global positioning system (GPS) stations within 20 km of of these areas that could be contaminated by the anthropogenic deformation. At sites where we performed a full time series analysis, we found a mix of steady and time-variable deformation rates. For example, at the East Mesa Geothermal Field in California, we found an area that changed from subsidence to uplift around 2006, even though publicly available records of pumping and injection showed no change during that time. We illustrate selected non-detections from wastewater injection in Oklahoma and eastern Texas, where we found that the detection threshold with available data is >0.5 cm/yr. This places into doubt previous results claiming detection below this threshold in eastern Texas. However, we found likely injection-induced uplift in a different area of eastern Texas at rates in excess of −2 cm/yr. We encourage others to expand the database in space and time in the supplemental material.

Highlights

We present a catalog of anthropogenic deformation signals in North American over the period 1992–2015 that have been detected primarily using satellite interferometric synthetic-aperture radar (InSAR), based on both the scientific literature and new data analysis
North America? In what areas are human activities occurring, but without deformation that can be detected by available satellite-based InSAR catalogs? we describe the InSAR data used to create the catalog of anthropogenic ground deformation, how the cause of the deformation was assessed, and examine the characteristics of this catalog, which is fully available in the supplemental material
The rest of the anthropogenic signals were identified through literature review, and most of these signals were confirmed through our InSAR analysis

Summary

Introduction

Human activity, such as mining, extraction of ground water and hydrocarbons, injection of fluid to enhance secondary recovery of hydrocarbons or dispose of wastewater, and utilization of geothermal fields, can cause displacements of the Earth’s surface that scientists can measure from space (e.g., [1,2]) This anthropogenic deformation is important to quantify for several reasons—(1) it can present a hazard to infrastructure (e.g., [3,4]); (2) it contaminates precise measurements of other types of deformation (e.g., magmatic, tectonic, or glacial isostatic adjustment; [5,6,7,8,9]); (3) the Earth’s response to known pumping, surface change, or mining activity can provide otherwise inaccessible information about the subsurface (e.g., [10,11]); and (4) when there is damage, discriminating anthropogenic and natural deformation can have implications for liability—for example deformation ( subsidence) can exacerbate natural hazards like flooding and sea level rise (e.g., [12,13]). For example: What are the dominant causes of anthropogenic ground deformation and does the dominant source vary with location in

Results

Discussion

Conclusion