Inner Core Rotation Captured by Earthquake Doublets and Twin Stations
نویسندگان
چکیده
The Earth's solid inner core (IC) is generally believed to rotate relative the mantle, but proposal remains controversial. Here we use seven waveform doublets in South Sandwich Islands region with time lapses of 5.8–17.0 years that are recorded by two close stations Kyrgyzstan virtually same epicentral distance. fortuitous geometry allows precise measurements IC temporal changes and underlying local structure at time. remarkable observations waveforms spatial-temporal show unequivocally must have shifted (rotated) eastward 1991–2010 help determine accurately average rotation rate as 0.127 ± 0.006°/yr 95% confidence level during span.
منابع مشابه
Inner core differential motion confirmed by earthquake waveform doublets.
We analyzed 18 high-quality waveform doublets with time separations of up to 35 years in the South Sandwich Islands region, for which the seismic signals have traversed the inner core as PKP(DF). The doublets show a consistent temporal change of travel times at up to 58 stations in and near Alaska, and they show a dissimilarity of PKP(DF) coda. Using waveform doublets avoids artifacts of earthq...
متن کاملWide-scale detection of earthquake waveform doublets and further evidence for inner core super-rotation
S U M M A R Y We report on more than 100 earthquake waveform doublets in five subduction zones, including an earthquake nest in Bucaramanga, Colombia. Each doublet is presumed to be a pair of earthquakes that repeat at essentially the same location. These doublets are important for studying earthquake physics, as well as temporal changes of the inner core. Particularly, our observation from one...
متن کاملComment on “ The existence of an inner core super - rotation questioned by teleseismic doublets ”
Poupinet et al. [J. Geophys. Res. 89 (1984) 5719] presented a new methodology for testing whether the PKP travel times observed at College, Alaska station from South Sandwich Islands earthquakes indicate inner core rotation. They applied the method to seven events and concluded that there is no evidence for PKP(DF) times increasing systematically with event dates, and therefore no reason to pos...
متن کاملInner-core Anisotropy and Rotation
■ Abstract This paper reviews recent research focused on the Earth’s inner core. Large inner-core traveltime anomalies and the anomalous splitting of core-sensitive free oscillations strongly suggest that the inner core is anisotropic. Initial models involved a simple, constant or depth-dependent cylindrical anisotropy at a level less than a few percent. Recent observations suggest that its eas...
متن کاملInner core rotation from event-pair analysis
The last decade has witnessed an animated debate on whether the inner core rotation is a fact or an artifact. Here we examine the temporal change of inner core waves using a technique that compares differential travel times at the same station but between two events. The method does not require precise knowledge of earthquake locations and earth models. The pairing of the events creates a large...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Geophysical Research Letters
سال: 2022
ISSN: ['1944-8007', '0094-8276']
DOI: https://doi.org/10.1029/2022gl098393