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Seismometers are highly sensitive instruments to not only ground motion but also many other nonseismic noise sources (e.g., temperature, pressure, and magnetic field variations). We show that the Alaska component of the Transportable Array is particularly susceptible to recording magnetic storms and other space weather events because the sensors used in this network are unshielded and magnetic flux variations are stronger at higher latitudes. We also show that vertical-component seismic records across Alaska are directly recording magnetic field variations between 40 and 800 s period as opposed to actual ground motion during geomagnetic events with sensitivities ranging from 0.004 to 0.48 (m/s2)/T. These sensitivities were found on a day where the root mean square variation in the magnetic field was 225 nT. Using a method developed by Forbriger (2007, his section 3.1), we show that improving vertical seismic resolution of an unshielded sensor by as much as 10 dB in the 100–400 s period band using magnetic data from a collocated three-component magnetometer is possible. However, due to large spatial variations in Earth’s magnetic field, this methodology becomes increasingly ineffective as the distance between the seismometer and magnetometer increases (no more than 200 km separation). A potential solution to this issue may be to incorporate relatively low-cost magnetometers as an additional environmental data stream at high-latitude seismic stations. We demonstrate that the Bartington Mag-690 sensors currently deployed at Global Seismographic Network sites are not only acceptable for performing corrections to seismic data, but are also capable of recording many magnetic field signals with similar signal-to-noise ratios, in the 20–1000 s period band, as the observatory grade magnetometers operated by the U.S. Geological Survey Geomagnetism Program. This approach would densify magnetic field observations and could also contribute to space weather monitoring by supplementing highly calibrated magnetometers with additional sensors.

Objectives The authors sought to evaluate the final 5-year safety and effectiveness of the platinum-chromium everolimus-eluting stent (PtCr-EES) in the randomized trial, as well as in 2 single-arm substudies that evaluated PtCr-EES in small vessels (diameter Background In the multicenter, randomized PLATINUM (PLATINUM Clinical Trial to Assess the PROMUS Element Stent System for Treatment of De Novo Coronary Artery Lesions), the PtCr-EES was noninferior to the cobalt-chromium everolimus-eluting stent (CoCr-EES) at 1 year in 1,530 patients undergoing percutaneous coronary intervention. Methods Patients with 1 or 2 de novo coronary artery lesions (reference vessel diameter 2.50 to 4.25 mm, length ≤24 mm) were randomized 1:1 to PtCr-EES versus CoCr-EES. All patients in the substudies received PtCr-EES. The primary endpoint was target lesion failure (TLF), a composite of target vessel-related cardiac death, target vessel-related myocardial infarction, or ischemia-driven target lesion revascularization. Results In the randomized trial, the 5-year TLF rate was 9.1% for PtCr-EES and 9.3% for CoCr-EES (hazard ratio [HR]: 0.97; p = 0.87). Landmark analysis demonstrated similar TLF rates from discharge to 1 year (HR: 1.12; p = 0.70) and from 1 to 5 years (HR: 0.90; p = 0.63). There were no significant differences in the rates of cardiac death, myocardial infarction, target lesion or vessel revascularization, or stent thrombosis. PtCr-EES had 5-year TLF rates of 7.0% in small vessels and 13.6% in long lesions. Conclusions PtCr-EES demonstrated comparable safety and effectiveness to CoCr-EES through 5 years of follow-up, with low rates of stent thrombosis and other adverse events. The 5-year event rates were also acceptable in patients with small vessels and long lesions treated with PtCr-EES. (The PLATINUM Clinical Trial to Assess the PROMUS Element Stent System for Treatment of De Novo Coronary Artery Lesions [PLATINUM]; NCT00823212; The PLATINUM Clinical Trial to Assess the PROMUS Element Stent System for Treatment of De Novo Coronary Artery Lesions in Small Vessels [PLATINUM SV]; NCT01498692; The PLATINUM Clinical Trial to Assess the PROMUS Element Stent System for Treatment of Long De Novo Coronary Artery Lesions [PLATINUM LL]; NCT01500434)