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Reposted by Bertrand Delouis

Dr. Alice-Agnes Gabriel @inseismoland.bsky.social · 4d

Do Coupled Megathrusts Rupture?

In our new preprint, Bar Oryan and I present
the first global analysis of the relationship between kinematic geodetic coupling and earthquake slip models across 12 subduction zones and 61 megathrust earthquakes.

eartharxiv.org/repository/v...

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GFZ Helmholtz-Zentrum für Geoforschung @gfz.bsky.social · 17d

Our latest study in Nature, together with colleagues from @geomarkiel.bsky.social and universities from Greece, shows what happened beneath Santorini earlier this year when tens of thousands earthquakes shook the islands and the seafloor. It was magma. We also have 1/2

www.gfz.de/en/press/new...

Magma displacement triggered tens of thousands of earthquakes

Magma displacement triggered tens of thousands of earthquakes: Analysis of the swarm of earthquakes around Santorini in early 2025 reveals causes and development of the seismic crisis

www.gfz.de

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Bertrand Delouis @bertranddelouis.bsky.social · Jul 21

The vast majority of the aftershocks is located to the East or South-East of the epicenter, not to the North-West of it:

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Julie Elliott @julieelliott.bsky.social · Jul 16

Quick map of M7.3 earthquake offshore the Alaska Peninsula. Today's earthquake (green) has a very similar focal mechanism to the M7.8 2020 Sand Point event, which was dominantly strike-slip but caused a tsunami. Based on depths of mainshock and early aftershocks, could be an upper plate event. ⚒️

Map showing earthquakes and past ruptures along the Alaska Peninsula. Five large earthquakes (7.2-8.2) have occurred since July 2020. Green focal mechanism shows a healthy amount of strike slip and marks today's event. Red contours show past rupture areas for large earthquakes. Black contours show 1-m slip intervals for the 2020 M7.8 Simeonof earthquake (Xiao et al., 2021). Purple contours show 1-m slip intervals for the 2021 M8.2 Chignik earthquake (Elliott et al., 2022). Light blue and cyan contours show possible 1-m slip intervals for 1938 M8.3 earthquake (Freymueller et al., 2021). Blue dots are continuous GNSS sites. Gray shading shows geodetic coupling estimates. 1.0 means plates are fully locked together; 0 means plates are freely slipping past each other.

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Bertrand Delouis @bertranddelouis.bsky.social · Jul 17

By comparison, the USGS solution

earthquake.usgs.gov/earthquakes/...

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Bertrand Delouis @bertranddelouis.bsky.social · Jul 17

Auto slipmap with regional records (SLIPNEAR method, Géoazur/OCA) M 7.3 - ALASKA - 2025-07-16 20:37:39 (UTC)

Plane striking N343 (NNW-SSE) shown.

Rupture direction to the South-East constrained by nearby stations (quite opposite to the USGS result).

Thanks to seismic records through IRIS

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Bertrand Delouis @bertranddelouis.bsky.social · Jun 8

Slipmap for the earthquake of Colombia M6.4 of 8 June 2025. SLIPNEAR method.

Preferred rupture plane (strike,dip,rake) : 50 20 112
with confidence : 47.%
Discrimination among the two nodal planes
may be considered reliable only if
this confidence is larger or equal to 70%

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aldozollo.bsky.social @aldozollo.bsky.social · May 23

Our new study just out in #NatureCommunications maps the deep structure of Campi Flegrei with unprecedented detail—and found that pressurized fluids, not magma, are the main cause of current unrest 🇮🇹
Read the full study here:
🔗 doi.org/10.1038/s414...

3D structure and dynamics of Campi Flegrei enhance multi-hazard assessment - Nature Communications

This study maps Campi Flegrei caldera’s internal structure, linking a gas-enriched reservoir and a deformed caprock to ground uplift and earthquakes. Land instability, seismic events and the risk of a...

doi.org

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Bertrand Delouis @bertranddelouis.bsky.social · May 2

Auto slipmap with regional records (SLIPNEAR method, Géoazur/OCA) M 7.5 – DRAKE PASSAGE 2025-05-02 12:58:27.5 UTC

Rupture plane not selected in an automated way. Plane dip to the NE (strike 326) shown.

Rupture propagation mainly to the SE.

Thanks to seismic records through IRIS

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Earthquake information from Geoscope Observatory @geoscope-ipgp.bsky.social · Apr 25

Mw=6.2, NEAR COAST OF ECUADOR (Depth: 21 km), 2025/04/25 11:44:55 UTC - Full details here: http://geoscope.ipgp.fr/scripts/seismes/fiche.php?seis=us7000pv06

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Bertrand Delouis @bertranddelouis.bsky.social · Apr 25

Thank you. Very interesting the hypotheses in this paper explaining why ruptures to the East are predominent in this fault branch.

Bertrand Delouis @bertranddelouis.bsky.social · Apr 24

The slip distribution coincides well with the aftershock distribution (EMSC), confirming ~15-20 km of rupture propagation towards the East :

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Earthquake information from Geoscope Observatory @geoscope-ipgp.bsky.social · Apr 23

Mw=6.3, TURKEY (Depth: 4 km), 2025/04/23 09:49:10 UTC - Full details here: http://geoscope.ipgp.fr/scripts/seismes/fiche.php?seis=us7000pufs

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Bertrand Delouis @bertranddelouis.bsky.social · Apr 23

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Bertrand Delouis @bertranddelouis.bsky.social · Apr 23

Auto slipmap with regional records (SLIPNEAR method, Géoazur/OCA) M 6.2 – Western Turkey - 2025-04-23 09:49:10 (UTC)

EW nodal plane preferred with confidence 65% as the rupture plane. Rupt propagation mainly to the East.

Thanks to seismic records from KOERI

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Bertrand Delouis @bertranddelouis.bsky.social · Apr 14

Auto solution FMNEAR (Géoazur/OCA) with regional records for the M 5.2 – Southern California, 2025-04-14 17:08:28 UTC (Loc EMSC used to trigger inversion).

Thanks to the seismic records provided through IRIS and SCEDC

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Gareth Funning @gfun.earth · Apr 2

The whole #MyanmarEarthquake rupture in one interferogram! This is three consecutive wide swath frames of ALOS-2 data, provided by JAXA through agreement with NASA. The line-of-sight (LOS) is ~perpendicular to fault strike, so most of what you see is vertical motion at bends and steps of the fault.

A radar interferogram covering 17.5 to 23.5 degrees north, in Myanmar. Tightly clustered fringes delimit the likely 2025 earthquake rupture zone.

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Robin Lacassin @rlacassin.bsky.social · Apr 2

High resolution MAXAR satellite image reveals the #Myanmar #earthquake surface rupture north of the town of Sagaing. It is close to epicenter and N tip of the >400km long rupture.

Right-lateral offset of ~3.2m is clearly illustrated by the distorsion and lateral shift of a dirt road striking E-W.

Left: excerpt of the satellite image. Different fields, dirt roads and paths, houses are visible. The earthquake rupture is visible as darker lines cutting across fields and roads. A clear lateral offset of a dirt road is also visible. To the right, same image with the earthquake rupture mapped in red.

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Dr. Eric J. Fielding, PhD @ericfielding.mastodon.social.ap.brid.gy · Apr 1

NASA JPL ARIA project analysis of data from Copernicus Sentinel-2 optical and Sentinel-1 radar images measured the slip on the Sagaing Fault in Myanmar. Quick preliminary map. More details later. Fault ruptured about 500 km (300 miles) in the magnitude 7.7 […]

[Original post on mastodon.social]

Map of Myanmar area showing sharp color change along the fault running roughly north-south. Red on west side where land moved northward.

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Rich Briggs @rangefront.bsky.social · Apr 1

Remote surface rupture observations for the M7.7 2025 Myanmar earthquake - soft rollout!

doi.org/10.5066/P1RY...

Simple fault trace and slip distribution from pixel tracking, high-res from available imagery. Watch for updates!

⚒️ USGS and collaborators effort led by @nadinegrr.bsky.social 🙏

Screenshot of Myanmar M7.7 surface rupture map service

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Dr. Paula Marques Figueiredo @paleoquake.bsky.social · Apr 1

www.linkedin.com/posts/remote...

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Dr. Judith Hubbard @judithgeology.bsky.social · Mar 29

The latest models from the USGS show slip, and associated strong shaking, extending much further to the south. Here I have plotted contours of estimated shaking over a map of population density. Note that the fault runs south through a narrow valley that is densely populated.

⚒️ 🧪 Myanmar earthquake

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Henning @geohenning.bsky.social · Mar 28

Cross-section of slip distribution by the USGS for the M7.7 Myanmar earthquake. Slip occured along the distance of about 250 km, maximum ~horizontal slip of 5.1 meters. ⚒🧪

Cross-section of slip distribution. The strike direction is indicated above each fault plane and the hypocenter location is denoted by a star. Slip amplitude is shown in color and the motion direction of the hanging wall relative to the footwall (rake angle) is indicated with arrows. Contours show the rupture initiation time in seconds.

Surface projection of the slip distribution superimposed on GEBCO bathymetry. Thick white lines indicate major plate boundaries [Bird, 2003]. Gray circles, if present, are aftershock locations, sized by magnitude.

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Lidong Bie @lidongbie.bsky.social · Mar 28

Looking at the historical earthquake map and the preliminary USGS slip model below, it seems today's large earthquake filled partly the gap between 20 and 22 degrees North latitude.

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Stephen Hicks @seismo-steve.bsky.social · Mar 28

Preliminary back-projection which seems to confirm the finite fault model: www.linkedin.com/posts/hongju...

For the M7.7 Myanmar earthquake occurred in 28 March 2025, we produced the… | Hongjun Si

For the M7.7 Myanmar earthquake occurred in 28 March 2025, we produced the following analysis results for emergency response: (1)Energy radiation from the…

www.linkedin.com

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