ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Unknown

Complex and diverse rupture processes of the 2018 Mw 8.2 and Mw 7.9 Tonga-Fiji deep earthquakes (2019)

Fan, Wenyuan ; Wei, S. Shawn ; Tian, Dongdong ; [et al.]

American Geophysical Union

add to mindlist on the mindlist

Details

Publication Date: 2022-10-26

Description: Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 46(5), (2019):2434-2448, doi:10.1029/2018GL080997.

Description: Deep earthquakes exhibit strong variabilities in their rupture and aftershock characteristics, yet their physical failure mechanisms remain elusive. The 2018 Mw 8.2 and Mw 7.9 Tonga‐Fiji deep earthquakes, the two largest ever recorded in this subduction zone, occurred within days of each other. We investigate these events by performing waveform analysis, teleseismic P wave backprojection, and aftershock relocation. Our results show that the Mw 8.2 earthquake ruptured fast (4.1 km/s) and excited frequency‐dependent seismic radiation, whereas the Mw 7.9 earthquake ruptured slowly (2.5 km/s). Both events lasted ∼35 s. The Mw 8.2 earthquake initiated in the highly seismogenic, cold core of the slab and likely ruptured into the surrounding warmer materials, whereas the Mw 7.9 earthquake likely ruptured through a dissipative process in a previously aseismic region. The contrasts in earthquake kinematics and aftershock productivity argue for a combination of at least two primary mechanisms enabling rupture in the region.

Description: We thank the Editor Gavin Hayes and two anonymous reviewers for their helpful comments that improved the quality of the manuscript. The seismic data were provided by Data Management Center (DMC) of the Incorporated Research Institutions for Seismology (IRIS). The facilities of IRIS Data Services, and specifically the IRIS Data Management Center, were used for access to waveforms, related metadata, and/or derived products used in this study. IRIS Data Services are funded through the Seismological Facilities for the Advancement of Geoscience and EarthScope (SAGE) Proposal of the National Science Foundation under Cooperative Agreement EAR‐1261681. W. F. acknowledges supports from the Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution, with funding provided by the Weston Howland Postdoctoral Scholarship. S. S. W. and D. T. are supported by the MSU Geological Sciences Endowment.

Description: 2019-08-20

Keywords: Deep earthquakes ; Tonga ; Backprojection ; Source imaging

Repository Name: Woods Hole Open Access Server

Type: Article

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OA)

S·F·X

Fulltext

2

Unknown

Tidal and thermal stresses drive seismicity along a major Ross Ice Shelf rift (2019)

Olinger, Seth D. ; Lipovsky, Bradley P. ; Wiens, Douglas A. ; [et al.]

American Geophysical Union

add to mindlist on the mindlist

Details

Publication Date: 2022-10-26

Description: Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters, 46(12), (2019): 6644-6652, doi:10.1029/2019GL082842.

Description: Understanding deformation in ice shelves is necessary to evaluate the response of ice shelves to thinning. We study microseismicity associated with ice shelf deformation using nine broadband seismographs deployed near a rift on the Ross Ice Shelf. From December 2014 to November 2016, we detect 5,948 icequakes generated by rift deformation. Locations were determined for 2,515 events using a least squares grid‐search and double‐difference algorithms. Ocean swell, infragravity waves, and a significant tsunami arrival do not affect seismicity. Instead, seismicity correlates with tidal phase on diurnal time scales and inversely correlates with air temperature on multiday and seasonal time scales. Spatial variability in tidal elevation tilts the ice shelf, and seismicity is concentrated while the shelf slopes downward toward the ice front. During especially cold periods, thermal stress and embrittlement enhance fracture along the rift. We propose that thermal stress and tidally driven gravitational stress produce rift seismicity with peak activity in the winter.

Description: NSF grants PLR‐1142518, 1141916, and 1142126 supported S. D. Olinger and D. A. Wiens, R. C. Aster, and A. A. Nyblade respectively. NSF grant PLR‐1246151 supported P. D. Bromirski, P. Gerstoft, and Z. Chen. NSF grant OPP‐1744856 and CAL‐DPR‐C1670002 also supported P. D. Bromirski. NSF grant PLR‐1246416 supported R. A. Stephen. The Incorporated Research Institutions for Seismology (IRIS) and the PASSCAL Instrument Center at New Mexico Tech provided seismic instruments and deployment support. The RIS seismic data (network code XH) are archived at the IRIS Data Management Center (http://ds.iris.edu/ds/nodes/dmc/). S. D. Olinger catalogued and located icequakes, analyzed seismicity and environmental forcing, and drafted the manuscript. D. A. Wiens and B. P. Lipovsky provided significant contributions to the analysis and interpretation of results and to the manuscript text. D. A. Wiens, R. C. Aster, A. A. Nyblade, R. A. Stephen, P. Gerstoft, and P. D. Bromirski collaborated to design and obtain funding for the deployment. D. A. Wiens, R. C. Aster, R. A. Stephen, P. Gerstoft, P. D. Bromirski, and Z. Chen deployed and serviced seismographs in Antarctica. All authors provided valuable feedback, comments, and edits to the manuscript text. Special thanks to Patrick Shore for guidance throughout the research process.

Description: 2019-11-23

Keywords: Ross Ice Shelf ; Glacial seismology ; Glaciology ; Ice shelf rifting ; Antarctica

Repository Name: Woods Hole Open Access Server

Type: Article

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OA)

S·F·X

Fulltext

3

Unknown

Ross ice shelf icequakes associated with ocean gravity wave activity (2019)

Chen, Zhao ; Bromirski, Peter D. ; Gerstoft, Peter ; [et al.]

American Geophysical Union

add to mindlist on the mindlist

Details

Publication Date: 2022-10-26

Description: Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 46(15), (2019): 8893-8902, doi:10.1029/2019GL084123.

Description: Gravity waves impacting ice shelves illicit a suite of responses that can affect ice shelf integrity. Broadband seismometers deployed on the Ross Ice Shelf, complemented by a near‐icefront seafloor hydrophone, establish the association of strong icequake activity with ocean gravity wave amplitudes (AG) below 0.04 Hz. The Ross Ice Shelf‐front seismic vertical displacement amplitudes (ASV) are well correlated with AG, allowing estimating the frequency‐dependent transfer function from gravity wave amplitude to icefront vertical displacement amplitude (TGSV(f)). TGSV(f) is 0.6–0.7 at 0.001–0.01 Hz but decreases rapidly at higher frequencies. Seismicity of strong icequakes exhibits spatial and seasonal associations with different gravity wave frequency bands, with the strongest icequakes observed at the icefront primarily during the austral summer when sea ice is minimal and swell impacts are strongest.

Description: Bromirski, Gerstoft, and Chen were supported by NSF grant PLR‐1246151. Bromirski also received support from NSF grant OPP‐1744856 and CAL‐DPR‐C1670002. Stephen, Wiens, Aster, and Nyblade were supported under NSF grants PLR‐1246416, 1142518, 1141916, and 1142126, respectively. Lee and Yun were support by a research grant from the Korean Ministry of Oceans and Fisheries (KIMST20190361; PM19020). Seismic instruments and on‐ice support were provided by the Incorporated Research Institutions for Seismology (IRIS) through the PASSCAL Instrument Center at New Mexico Tech. The RIS and KPDR seismic data are archived at the IRIS Data Management Center, http://ds.iris.edu/ds/nodes/dmc/, with network codes XH and KP, respectively. The facilities of the IRIS Consortium are supported by the National Science Foundation under Cooperative Agreement EAR‐1261681 and the DOE National Nuclear Security Administration. We thank Patrick Shore, Michael Baker, Cai Chen, Robert Anthony, Reinhard Flick, Jerry Wanetick, Weisen Shen, Tsitsi Madziwa Nussinov, and Laura Stevens for their help with field operations. Logistical support from the U.S. Antarctica Program and staff at McMurdo Station was critical and is much appreciated.

Description: 2020-02-01

Keywords: Icequake ; Ice shelf ; Gravity wave ; Transfer function

Repository Name: Woods Hole Open Access Server

Type: Article

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OA)

S·F·X

Fulltext

4

Unknown

Upper mantle hydration indicated by decreased shear velocity near the Southern Mariana Trench from Rayleigh wave tomography (2021)

Zhu, Gaohua ; Wiens, Douglas A. ; Yang, Hongfeng ; [et al.]

American Geophysical Union

add to mindlist on the mindlist

Details

Publication Date: 2022-05-27

Description: Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 48(15), (2021): e2021GL093309, https://doi.org/10.1029/2021GL093309.

Description: Reduction of seismic velocities has been employed to study the hydration of incoming plates and forearc mantle in recent years. However, few constraints have been obtained in the Southern Mariana Trench. We use an ocean bottom seismograph (OBS) deployment to conduct Rayleigh wave tomographic studies to derive the SV-wave velocity structure near the Southern Mariana Trench. Measured group and phase velocities as a function of period are inverted to determine the SV-wave velocity using a Bayesian Monte Carlo algorithm. The incoming Pacific Plate is characterized by low velocities (3.6–4.1 km/s) within the upper ∼25 km of the mantle near the trench, indicating extensive mantle hydration of the incoming plate in southern Mariana. The velocity reduction in the forearc mantle is not as large as in central Mariana, most likely indicating a lower forearc serpentinization in this region, which is consistent with the absence of serpentinite mud volcanoes.

Description: This study is supported by the Hong Kong Research Grant Council Grants (No. 14304820), National Natural Science Foundation of China (Nos. 91858207, 41890813, and 91628301), Chinese Academy of Sciences (Nos. Y4SL021001, QYZDY-SSW-DQC005, 133244KYSB20180029, and COMS2019Q10), and National Key R&D Program of China (Nos. 2018YFC0309800, 2018YFC0310105, and 2018YFC0308003), Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (No. GML2019ZD0205), Faculty of Science at CUHK.

Description: 2022-01-26

Repository Name: Woods Hole Open Access Server

Type: Article

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OA)

S·F·X

Fulltext

5

Unknown

Lithospheric erosion in the Patagonian slab window, and implications for glacial isostasy (2022)

Mark, Hannah F. ; Wiens, Douglas A. ; Ivins, Erik ; [et al.]

American Geophysical Union

add to mindlist on the mindlist

Details

Publication Date: 2022-07-18

Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 49(2), (2022): e2021GL096863, https://doi.org/10.1029/2021GL096863.

Description: The Patagonian slab window has been proposed to enhance the solid Earth response to ice mass load changes in the overlying Northern and Southern Patagonian Icefields (NPI and SPI, respectively). Here, we present the first regional seismic velocity model covering the entire north-south extent of the slab window. A slow velocity anomaly in the uppermost mantle indicates warm mantle temperature, low viscosity, and possibly partial melt. Low velocities just below the Moho suggest that the lithospheric mantle has been thermally eroded over the youngest part of the slab window. The slowest part of the anomaly is north of 49°S, implying that the NPI and the northern SPI overlie lower viscosity mantle than the southern SPI. This comprehensive seismic mapping of the slab window provides key evidence supporting the previously hypothesized connection between post-Little Ice Age anthropogenic ice mass loss and rapid geodetically observed glacial isostatic uplift (≥4 cm/yr).

Description: The facilities of the IRIS Consortium are supported by the National Science Foundation’s SAGE Award under Cooperative Support Agreement EAR-1851048. The GUANACO project is funded by the National Science Foundation under grants EAR-1714154 to WUSTL and EAR-1714662 to SMU, and Erik R. Ivins was supported by NASA under grant NNH19ZDA001N-GRACEFO.

Description: 2022-07-18

Repository Name: Woods Hole Open Access Server

Type: Article

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OA)

S·F·X

Fulltext

6

Unknown

Seismicity of the incoming plate and forearc near the Mariana Trench recorded by ocean bottom seismographs (2020)

Eimer, Melody ; Wiens, Douglas A. ; Cai, Chen ; [et al.]

American Geophysical Union

add to mindlist on the mindlist

Details

Publication Date: 2022-05-26

Description: Author Posting. © American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 21(4), (2020): e2020GC008953, doi:10.1029/2020GC008953.

Description: Earthquakes near oceanic trenches are important for studying incoming plate bending and updip thrust zone seismogenesis, yet are poorly constrained using seismographs on land. We use an ocean bottom seismograph (OBS) deployment spanning both the incoming Pacific Plate and the forearc to study seismicity near the Mariana Trench. The yearlong deployment in 2012–2013 consisted of 20 broadband OBSs and 5 suspended hydrophones, with an additional 59 short period OBSs and hydrophones recording for 1 month. We locate 1,692 earthquakes using a nonlinear method with a 3D velocity model constructed from active source profiles and surface wave tomography results. Events occurring seaward of the trench occur to depths of ~35 km below the seafloor, and focal mechanisms of the larger events indicate normal faulting corresponding to plate bending. Significant seismicity emerges about 70 km seaward from the trench, and the seismicity rate increases continuously towards the trench, indicating that the largest bending deformation occurs near the trench axis. These plate‐bending earthquakes occur along faults that facilitate the hydration of the subducting plate, and the lateral and depth distribution of earthquakes is consistent with low‐velocity regions imaged in previous studies. The forearc is marked by a heterogeneous distribution of low magnitude (〈5 Mw) thrust zone seismicity, possibly due to the rough incoming plate topography and/or serpentinization of the forearc. A sequence of thrust earthquakes occurs at depths ~10 km below seafloor and within 20 km of the trench axis, demonstrating that the megathrust is seismically active nearly to the trench.

Description: We thank the captains, crew, and science teams on the R/V Thompson, Langseth and Melville, Dr. Patrick Shore for providing data management and technical support, and Ivan Komarov and Zhengyang Zhou for assistance with data analysis. We thank Ingo Grevemeyer and an anonymous reviewer for their comments to improve the manuscript. Instrumentation and technical support was provided by the PASSCAL program of the Incorporated Research Institutions in Seismology (IRIS) and the Woods Hole, Lamont‐Doherty, and Scripps facilities of the Ocean Bottom Seismograph Instrumentation Pool (OBSIP). Funding was provided by the MARGINS/GeoPRISMS program through NSF grant OCE‐0841074 (D.A.W.) and the Spencer T. and Ann W. Olin Fellowship program at Washington University in Saint Louis. Raw seismic data used in this study are available through the Data Management Center of the Incorporated Research Institutions for Seismology (http://www.iris.edu/dms/nodes/dmc) under network IDs XF and MI.

Description: 2020-10-06

Repository Name: Woods Hole Open Access Server

Type: Article

Permalink