...Stefanie Donner; Chin‐Jen Lin; Céline Hadziioannou; André Gebauer; Frank Vernon; Duncan Carr Agnew; Heiner Igel; Ulrich Schreiber; Joachim Wassermann ABSTRACT The unique instrument setting at the Piñon Flat Observatory in California is used to simultaneously measure 10 out of the 12 components...

... and elastic-wave theory by comparing such estimated strains with strains measured on a three-component long-base strainmeter system at Piñon Flat, California. We quantify the uncertainties and errors through cross-spectral analysis of data from three regional earthquakes (the M 0 = 4 × 10 17 N-m St. George...

...Duncan Carr Agnew; Frank K. Wyatt Abstract We describe observations at Piñon Flat Observatory of preseismic, co-seismic, and postseismic strain and tilt changes associated with the Superstition Hills earthquake sequence of 24 November 1987. The data come from two long-base strainmeters, one long...

...Lei Qin; Frank L. Vernon; Christopher W. Johnson; Yehuda Ben‐Zion Abstract We investigate coherences of seismic data recorded during three years (2015–2017) at the Piñon Flats Observatory (PY) array and a collocated 148 m deep borehole station B084, along with oceanic data from a buoy southwest...

...Frank K. Wyatt; Duncan Carr Agnew; Michael Gladwin Abstract We describe, and attempt to interpret, continuous measurements of strains and tilts made at Piñon Flat Observatory (PFO) before, during, and after the Landers and Joshua Tree earthquake sequences. These data show substantial transient...

... two additional stations both collocated at the Piñon Flats Observatory (PFO) in southern California (networks TA and Incorporated Research Institutions for Seismology [IRIS] International Deployment of Accelerometers [IDA]). We find a good agreement between the acceleration‐tilt derived from the TA...

... and teleseismic distances. The formulas are fits to data from 89 large (6.5≤ M w ≤9.0) shallow earthquakes, with source distances between 500 and 16,000 km, recorded between 1977 and 2013 by three long‐base laser strainmeters at Piñon Flat Observatory in southern California; these strainmeters provide uniquely...

... of long-base strainmeters sited on low-velocity materials (such as the 732-m-long strainmeters at Piñon Flat Observatory) may require correction for amplitude distortion. Bulletin of the Seismological Society of America, Vol. 87, No. 4, pp. 1078-1080, August 1997 Frequency Response of a Strainmeter...

...G. Eli Baker; J. Bernard Minster; George Zandt; H. Gurrola Abstract We use teleseismic P waves recorded at Piñon Flat Observatory ( PFO ) to constrain the three-dimensional crustal and upper-mantle velocity structure beneath the station. By forward modeling radial receiver function waveforms, we...

... earthquake prediction. The 1992 Landers earthquake ( M 7.3) had a distinctive foreshock sequence and initiated only 70 km from the strain meters at the Piñon Flat Observatory ( PFO ). We use this earthquake to investigate the validity and usefulness of Ohnaka's model. The accurate relocations of Dodge et al...

... (Keenwild fire station), which is located along a ridge line about 8.7 km east of the San Jacinto Fault zone. Station PFO (Piñon Flat Observatory), chosen for the second site, is another 6 km further to the east of station KNW and is located on a gently sloping hillside. We logged each borehole for P...

...N. E. King; D. C. Agnew; F. Wyatt Abstract We present a procedure for comparing strain events at different sites, and apply it to observations for the Homestead Valley earthquake sequence of 15 March 1979. Coseismic strain steps occurred on two laser strainmeters at Piñon Flat Observatory ( PFO...