...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...

...Stanley J. Radzevicius; Gary L. Pavlis Abstract We analyze data from two orthogonal seismic lines 336 m in length collected at Pinon Flat, California, over weathered granodiorite bedrock. Each line was made up of 10 reversed segments 84 m in length. We analyzed the first arrivals from these data...

...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...

... 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...

...-estimators applied to individual phase factors in the complex plane. The method is applied to data from three-component array experiments conducted at Piñon Flats, California, in 1990 and 1991. We find remarkable departures of P -wave particle motions from the pure longitudinal motion expected...

.... This phenomenon, however, is strongly frequency dependent. At the Piñon Flat site, variations in power spectral estimates exceed a factor of 100 at frequencies over 4 Hz. Analysis of teleseismic signals, however, demonstrates that these variations diminish rapidly at lower frequencies and falls to negligible...

... large‐scale ring lasers (G‐ring and ROMY) and array‐derived rotations (Piñon Flats Observatory array, Gräfenberg array, and ROMY array). We propose this RLNM to be useful as guidance for the development of high‐performance rotation instrumentation for seismic applications in a range of 2–50 s. Achieving...

... 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...

...Figure 4. Example of two small local tremors measured in Piñon Flat. The observed rotation rates are up to 150 nrad/sec. ...

... 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...

... local and regional earthquakes on digital recorders, both at the surface and in boreholes, at two rock sites and one basin site in the San Jacinto mountains, southern California. The two rock sites, Keenwild and Piñon Flat, are located on granitic bedrock of the southern California peninsular ranges...

... 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...

...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...

... at remote sites. Such seismometers, using Mark Products L-22D 2-Hz geophones, have been installed at several sites in California: at the bottom of adjacent boreholes ∼ 150 and ∼ 300 m deep, in granite at station KNW near Keenwild and at Piñon Flat of the Anza digital seismic array, and at the bottom...