Funding for this research was provided by:
National Science Foundation (NSF 15-20864)
Received: 4 August 2017
Accepted: 20 February 2018
First Online: 8 March 2018
: We gratefully acknowledge the support provided by the National Science Foundation (NSF) under Award Number 15-20864. We thank C. A. Finn, G. M. Lucas, J. McCarthy, J. Slate and two anonymous referees for reading a draft manuscript. We thank A. Kelbert for useful conversations. The results presented in this paper rely on data collected at magnetic observatories. We thank the national institutes that support them and INTERMAGNET for promoting high standards of five magnetic observatory practice (ExternalRef removed). USArray MT TA project was led by PI Adam Schultz and Gary Egbert. They would like to thank the Oregon State University MT team and their contractors, lab and field personnel over the years for assistance with data collection, quality control, processing and archiving. We also thank numerous districts of the U.S. Forest Service, Bureau of Land Management, the U.S. National Parks, the collected State land offices, and the many private landowners who permitted access to acquire the MT TA data. USArray TA was funded through NSF Grants EAR-0323311, IRIS Subaward 478 and 489 under NSF Cooperative Agreement EAR-0350030 and EAR-0323309, IRIS Subaward 75-MT under NSF Cooperative Agreement EAR-0733069 under CFDA No. 47.050, and IRIS Subaward 05-OSU-SAGE under NSF Cooperative Agreement EAR-1261681.
: The authors declare that there are no competing interests.
: Not applicable.
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