Tag Archive for 'Seismic wave'

Schematic view of the propagation of seismic waves in the Martian crust and seismic conversions at the base of the discontinuity, at a depth of 10 km (6.2 miles). Image credit: IPGP.

NASA’s InSight Mission Detects Two Far-Side Marsquakes

Apr 27, 2022 by News Staff

In 2021, the Seismic Experiment for Interior Structure (SEIS) — the seismometer placed on the surface of Mars by NASA’s Interior Exploration using...

The landing site of InSight is marked by a blue triangle, while black stars denote the two identified marsquakes. The solid black lines demonstrate the Graben faults. The lower left inset map shows the global Martian topography, and the blue rectangular illustrates the research region. Image credit: Sun & Tkalčić, doi: 10.1038/s41467-022-29329-x.

Volcanic Activity Could Be Responsible for Triggering Marsquakes in Cerberus Fossae

Apr 6, 2022 by News Staff

Using seismic data from NASA’s Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander, planetary researchers...

Pachhai et al. employ seismic data analysis and high-resolution geodynamic modeling to study the origin of ultralow-velocity zones beneath the Coral Sea between Australia and New Zealand. Image credit: Pachhai et al., doi: 10.1038/s41561-021-00871-5.

Ultralow-Velocity Zones are Leftovers from Early Earth’s Magma Ocean, New Study Suggests

Jan 3, 2022 by News Staff

Ultra-low velocity zones sit beneath the central Pacific and Africa, atop the outer core of Earth. In these areas, seismic waves slow by as much as half,...

$Study area and hybrid-frequency waveform earthquakes (EHWs): (a) hydraulic fracturing activity and seismicity in northeast British Columbia, Canada; the top-right inset shows the geographic location of the study area (red rectangle); blue diamonds: hydraulic fracturing injection wells between January 1, 2014 and December 31, 2016, reported by the British Columbia Oil and Gas Commission; yellow dots: earthquakes during the same period; stars: 10 M 4-5 earthquakes since 2008; black rectangle: study area in which EHWs occurred; (b, c) comparison between representative examples of a typical induced event (black trace) and an EHW (purple trace); both waveforms are from the vertical component of station MG03 with comparable source-station distance (1.32 km vs. 1.65 km) and magnitudes (MW1.5); manually picked P/S-arrivals are marked; the comparison of P/S-pulse shape demonstrates the relatively wider pulses for EHWs; (d, e) the same as (b) and (c) but for waveforms recorded at station MG02; both events show longer coda durations with slightly larger epicentral distances; note that although both types of events have extended coda durations, the EHW contains a relatively larger proportion of lower-frequency energy in the coda. Image credit: Yu et al., doi: 10.1038/s41467-021-26961-x.$

Scientists Detect New Type of Fluid-Injection-Induced Earthquake

Dec 6, 2021 by News Staff

Unlike conventional earthquakes of the same magnitude, the newly-identified hybrid-frequency waveform earthquakes are slower and last longer. Study area...

NASA’s Cassini spacecraft captured this stunning mosaic of Enceladus on October 5, 2008 as the spacecraft sped away from this geologically active moon of Saturn. Image credit: NASA / JPL / Space Science Institute.

Tidal Stress May Be Causing Constant Icequakes along Enceladus’ Tiger Stripes

Jul 8, 2021 by News Staff

Saturn’s 500-km- (300-mile) diameter moon Enceladus is covered in ice which contains many long fractures or rifts, including fractures called tiger stripes....

The inner core of our planet has an inner core of its own, with crystals aligned in a different direction. Image credit: Lachina Publishing Services.

Geoscientists Confirm Existence of Earth’s Innermost Inner Core

Mar 8, 2021 by News Staff

Earth’s inner core has an inner core of its own and its distinct properties may point to a dramatic event in the history of our planet, according to...

$Earthquakes send sound waves through the Earth. Seismograms record the echoes as those waves travel along the core-mantle boundary, diffracting and bending around dense rock structures. Kim et al provide the first broad view of these structures, revealing them to be much more widespread than previously known. Image credit: Doyeon Kim, University of Maryland.$

Geophysicists Find Dense Rock Structures near Earth’s Core

Jun 16, 2020 by News Staff

In a new study, a team of geophysicists from the University of Maryland, Johns Hopkins University and Tel Aviv University has analyzed echoes of seismic...

$Yang & Song found that refracted waves (blue), rather than reflected waves (purple) change over time, providing the best evidence yet that Earth’s inner core is rotating. Image credit: Michael Vincent.$

Earth’s Inner Core is Rotating, Study Says

May 13, 2020 by News Staff

The inner core of the Earth is rotating at about 0.05-0.1 degrees per year, according to an analysis of seismic data from repeating earthquakes published...