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We estimated the spatial and temporal evolution of the preceding aseismic slip from January 2003 to January 2011, the coseismic slip of the Tohoku earthquake, and the postseismic slip after the earthquake based on global positioning system (GPS) data. Time‐dependent analysis indicates aseismic slip offshore of Miyagi and Fukushima prefectures from 2004 associated with a series of subduction earthquakes that overlap the aseismic slip area. These preceding aseismic and coseismic slip areas are centered between the centers of the coseismic and afterslip areas of the Tohoku earthquake offshore of Miyagi prefecture, while they overlap the coseismic and afterslip areas of the Tohoku earthquake off Fukushima prefecture. The timing of moment magnitude nine (Mw9) ‐class earthquakes appears to be controlled by multiple preceding slip events, smaller earthquakes and their afterslip. The preceding aseismic and coseismic slip decreased the coupling rate off the Tohoku coast, suggesting the possibility that the preceding slip represented a precursive stage of the Tohoku earthquake. The afterslip of the Tohoku earthquake occurred in an area where the coseismic slip was not large, complementing the large coseismic slip zone. The afterslip along Iwate‐Miyagi extends up to 80 km in depth and is currently the sole mechanism of strain release in this depth range. The source region of the anticipated Miyagi‐Oki earthquake shows small postseismic slip after the Tohoku earthquake, reflecting the energy release at the time of the earthquake. Aftershock activity is roughly governed by an afterslip process. Key Points Preceding slip occurred in a down‐dip area of the Tohoku earthquake Huge energy was accumulated near the Japan trench Afterslip is occurring in an area complementing the cosesimic rupture zone

The 2025 Mw ${\\mathrm{M}}_{\\mathrm{w}}$ 7.1 Dingri earthquake is a large normal‐faulting event within the Southern Tibet Rift System. We use space‐borne radar interferometry to investigate both coseismic rupture and ∼3‐month early afterslip. Results show that this event ruptured a west‐dipping (48°) fault, exhibiting a predominant normal dip‐slip of 4.7 m and a left‐lateral strike‐slip component of 3.2 m. Postseismic moment release (Mw ${\\mathrm{M}}_{\\mathrm{w}}$ 6.47) contributes 14.2% of the coseismic moment, predominantly (59%) from shallow afterslip (<28 km; maximum 0.3 m) exceeding the contribution from deep afterslip (<28 km; maximum 0.1 m). We find a depth‐dependent control on postseismic process: at 0–10 km, both 49% of aftershocks and substantial afterslip are driven by coseismic stress increases. Conversely, at 10–20 km depth, afterslip‐induced stress perturbations dominate, hosting 64% of aftershocks. The coseismic rupture kinematics reflect shallow crustal responses to deep tectonic processes, likely driven by the tearing of the Indian slab beneath southern Tibet.

The 2025 destructive Myanmar earthquake ruptured the previously recognized seismic gap along the Sagaing fault, with the longest ever recorded surface ruptures (∼ ${\\sim} $500 km). Here, we use SAR and optical images to characterize coseismic and early postseismic deformation of this event. North‐south displacements delineate the extent of surface ruptures, which are confined between historically ruptured regions, supported by dramatic slip reductions along the strike near the two rupture terminations. Coseismic slip model suggests two high‐slip zones of distinct sizes separated by a low‐slip zone. Coseismic slip has peak values at the surface almost all along the rupture, suggesting an absence of shallow slip deficits. Early postseismic deformation over ∼ ${\\sim} $1 month after the event is obtained by optical horizontal offsets. Rapid shallow afterslip (∼ ${\\sim} $5 cm/day) is only found along the southern segment, with some spatial overlap with coseismically slipped zones indicating frictional heterogeneity of the Sagaing fault.

Slow slip events (SSEs) release tectonic strain without causing sudden ground shaking. SSEs have been observed at many subduction zones, some dynamically triggered by stress changes due to the passage of seismic waves. However, there are limited observations of SSEs induced by post‐seismic deformation. Here, we report a significant increase in the recurrence rate of SSEs in the shallow portion of the Nicoya megathrust following the 2012 Mw 7.6 earthquake. These shallow SSEs occurred immediately updip of the large afterslip zone and their recurrence rate returned to pre‐earthquake level 1.5 years after the earthquake. In contrast, deeper SSE recurrence rate remained unchanged. Coulomb Failure Stress modeling indicates the shallow SSE area experienced substantial stress perturbation during afterslip, while the deeper megathrust did not. We interpret this temporarily increased shallow SSE recurrence rate to be driven by static stress loading from large afterslip.

Subducted rough topography complicates seismic and aseismic slip behavior. The 2024 M 7.1 Hyuganada earthquake occurred along the megathrust with ridge subduction. We inferred coseismic slip and afterslip using geodetic displacements to observationally illustrate the role of subducted seamounts in modulating seismic and aseismic slip processes. The inferred mainshock slip was confined in the down‐dip of the seamount, suggesting that the seamount impeded the mainshock rupture initiated under enhanced compression. The inferred afterslip peaked at the up‐dip of the mainshock peak with four aftershock clusters. Various onset timings of these clusters suggest the afterslip front migration slowed down when passing through the seamount. Little afterslip is inferred in a segment south of the mainshock, where the megathrust is somehow insusceptible to stress perturbation and seems to creep steadily across the mainshock occurrence. Our results geodetically highlight the mechanical heterogeneity of megathrust with ridge subduction at an order of 10 km. Plain Language Summary The 2024 Hyuganada earthquake occurred offshore Kyushu, Japan, where the oceanic Philippine Sea Plate subducts beneath the continental Amur plate with the highly variable seafloor topography called Kyushu‐Palau ridge. Numerical simulations have shown that the subduction of irregular topography yields complex fault slip behavior on and around it, so we observationally imaged fault slip processes during and after the 2024 earthquake to illustrate the role of seamounts in impacting slip behavior on the natural fault. Our analysis suggested that (a) the mainshock was impeded when its slip front entered the seamount zone and (b) the post‐mainshock aseismic afterslip front migrated more slowly when passing the seamount zone. We also did not identify a significant amount of slip in an along‐strike neighbor segment of the mainshock slip area during the week following the mainshock. This segment is somehow insusceptible to stress loading from nearby fault slips and seems to creep steadily across the mainshock time. Key Points The 2024 Hyuganada earthquake occurred at the leading edge of a seamount in the creeping megathrust due to a ridge subduction The subducted seamount probably impeded up‐dip mainshock rupture propagation and slowed up‐dip afterslip migration speed Geodetic and seismological observations illustrated heterogeneous mechanical characteristics of megathrust in Hyuganada at an order of 10 km

Shallow creep along strike‐slip faults is essential in releasing strain during earthquake cycles. However, its origin—whether inherent or triggered by earthquakes—remains debated. Using Interferometric Synthetic Aperture Radar phase‐gradient data, we map shear‐strain rates along the East Anatolian Fault Zone (EAFZ) before and after the 2020 Mw6.8 Elazığ and 2023 Mw7.8/Mw7.6 Kahramanmaraş earthquakes. The observed strain‐rate distributions strongly correlate with coseismic slips in the EAFZ. The stress‐driven afterslip model constrained by the phase‐gradient time series reproduces distinct decaying patterns of newly activated creeping segments, showing that rapid afterslip may decay slowly and keep slipping for decades. Our results reveal that large earthquakes can accelerate, expand, and trigger shallow fault creep, highlighting the roles of fault frictional properties and stress changes caused by nearby earthquakes. These findings provide new insights into fault creep mechanisms and their linkage to large earthquakes, with implications for faulting behaviors. Plain Language Summary Understanding the silent slips of large‐scale strike‐slip faults and their connection with nearby earthquakes is crucial for elucidating the mechanisms and causes of shallow creep, a topic that remains debated. Interferometric Synthetic Aperture Radar is a powerful tool for mapping millimeter‐level deformation and its spatial variation, that is, strain across faults with high spatial resolution. Here, we map and investigate the strain distribution of the East Anatolian Fault Zone from 2014 to 2023, with different periods spanning three significant earthquakes: the 2020 Mw 6.8 Elazığ earthquake and the 2023 Mw 7.8 and Mw 7.6 Kahramanmaraş earthquake sequence. The shear‐strain rates and the postseismic phase‐gradient time series clearly depict the spatial and temporal distribution of shallow slip before and after these earthquakes. Our results show a strong correlation between shallow slip and earthquakes, revealing how fault frictional properties and changes in seismic stress influence afterslip behavior. Simulation outcomes provide compelling evidence that afterslip triggered by earthquakes may continue for decades. Key Points We map the shear strain rates from the Interferometric Synthetic Aperture Radar phase gradient spanning two recent large earthquakes on the East Anatolian Fault The shear‐strain rates and coseismic slip models show that earthquakes can initiate, extend, and accelerate shallow creep Stress‐driven afterslip model constrained by time‐series phase gradients reveals earthquake‐triggered creep may continue for decades

Various earthquake models predict that aseismic slip modulates the seismic rupture process but actual observations of such seismic‐aseismic interaction are scarce. We analyze seismic and aseismic processes during the 2014 Iquique earthquake sequence. High‐rate Global Positioning System displacements demonstrate that most of the early afterslip is located downdip of the M 8.1 mainshock and is accompanied by decaying aftershock activity. An intriguing secondary afterslip peak is located ∼120 km south of the mainshock epicenter. The area of this secondary afterslip peak likely acted as a barrier to the propagating mainshock rupture and delayed the M 7.6 largest aftershock, which occurred 27 hr later. Interevent seismicity in this secondary afterslip area ended with a M 6.1 near the largest aftershock epicenter, kicking the largest aftershock rupture in the same area. Hence, the interevent afterslip likely promoted the largest aftershock nucleation by destabilizing its source area, favoring a rate‐dependent cascade‐up model. Plain Language Summary Subduction zone faults host both fast (regular earthquakes, seismic) and slow (aseismic) slip. Simulation models predict that slow slip can affect fast slip processes. We explored such an interaction taking place during the 2014 Iquique earthquake offshore northern Chile using observation data of crustal deformation by Global Positioning System and earthquakes. We discovered that the fast mainshock slip was terminated by a slowly slipping fault zone, which prevented the simultaneous occurrence of the largest aftershock. Furthermore, afterslip, one type of slow slip following the mainshock, helped the occurrence of the largest aftershock 27 hr after the mainshock. Therefore, the sequential occurrence of large earthquakes can be controlled by slowly slipping faults. Key Points Global Positioning System captured crustal deformation during 27 hr between the 2014 Iquique mainshock and its largest aftershock The mainshock and the largest aftershock areas are separated by an aseismic area, likely preventing both from rupturing as a single event The largest aftershock nucleation is a mixture of seismicity and decelerating afterslip, favoring a rate‐dependent cascade‐up model

The viscoelastic lower crust beneath Kyushu Island, influenced by the volcanic arc, interplays with active crustal faults in this region and helps to shape local tectonics. In this study, we employed a three‐dimensional viscoelastic finite element model to gain insights into the lithospheric rheology and crustal faulting kinematics, through modeling the postseismic deformation processes of the 2016 Mw 7.1 Kumamoto earthquake. Our model reveals a viscosity of 2 × 1020 Pa s for the lower crust and 2 × 1019 Pa s for the upper mantle. A reduced lower crust viscosity of 2 × 1019 Pa s in the volcanic arc area is required for better reproducing the Global Positioning System data. The stress‐driven afterslip decays rapidly over time and is up to 0.3 m within 5 years after the earthquake. We propose additional normal‐component afterslip to better explain the complex postseismic deformation in the near field, which may be due to the interaction between the fault and volcano Aso. Plain Language Summary We have derived the first 5‐year postseismic deformation at more than 200 Global Positioning System (GPS) stations following the 2016 Kumamoto earthquake to constrain the rheological properties beneath the Kyushu Island, as well as the evolution of afterslip. Test models have determined the viscosity of the lower crust and upper mantle to be ∼2 × 1020 and ∼2 × 1019 Pa s, respectively, while the viscosity of the lower crust beneath the volcanic arc is ∼2 × 1019 Pa s, notably lower than that of the other area. The lower crust viscosity in the Beppu‐Shimabara Graben, except the volcano dominant area, is estimated to be no smaller than 1020 Pa s. The complex near‐field postseismic deformation cannot be fully explained by one single deformation process. The viscoelastic relaxation and afterslip must both be at play to control the postseismic deformation. In addition to the rheological heterogeneity, the afterslip may also be heterogeneous. We propose additional afterslip possibly induced by the Aso volcano to better fit the near‐field GPS observations. Our models provide insights into the lithospheric structure of Kyushu Island and the intricate behavior of fault slips. Key Points We present a 3‐D finite element model to explore the postseismic viscoelastic relaxation and afterslip of the 2016 Kumamoto earthquake The steady‐state lower crust viscosity in Kyushu is ∼2 × 1020 Pa s, one order of magnitude higher than that beneath the volcanic arc region The complex near‐field postseismic deformation can be explained by the normal‐component afterslip induced by the Aso volcano

On 2 December 2020, an earthquake with a magnitude of Mw 4.5 occurred near the city of Thiva (Greece). The aftershock sequence, triggered by ruptures on or near the Kallithea fault, continued until January 2021. Seven months later, new seismic activity began a few kilometers west of the initial events, with the swarm displaying a general trend of spatiotemporal migration toward the east–southeast until the middle of 2022. In order to understand the physical and statistical pattern of the swarm, the seismicity was relocated using HypoDD, and the magnitude of completeness was determined using the frequency–magnitude distribution. In order to define the existence of spatiotemporal seismicity clusters in an objective way, the DBSCAN clustering algorithm was applied to the 2020–2022 Thiva earthquake sequence. The extracted clusters permit the analysis of the spatiotemporal scaling properties of the main clusters using the Non-Extensive Statistical Physics (NESP) approach, providing detailed insights into the nature of the long-term correlation of the seismic swarm. The statistical pattern observed aligns with a Q-exponential distribution, with qD values ranging from 0.7 to 0.8 and qT values from 1.44 to 1.50. Furthermore, the frequency–magnitude distributions were analyzed using the fragment–asperity model proposed within the NESP framework, providing the non-additive entropic parameter (qM). The results suggest that the statistical characteristics of earthquake clusters can be effectively interpreted using NESP, highlighting the complexity and non-additive nature of the spatiotemporal evolution of seismicity. In addition, the analysis of the properties of the seismicity clusters extracted using the DBSCAN algorithm permits the suggestion of possible physical mechanisms that drive the evolution of the two main and larger clusters. For the cluster that activated first and is located in the west–northwest part, an afterslip mechanism activated after the 2 September 2021, M 4.0 events seems to predominately control its evolution, while for the second activated cluster located in the east–southeast part, a normal diffusion mechanism is proposed to describe its migration pattern. Concluding, we can state that in the present work the application of the DBSCAN algorithm to recognize the existence of any possible spatiotemporal clustering of seismicity could be helping to provide detailed insight into the statistical and physical patterns in earthquake swarms.

We investigated the characteristics and mechanism of postseismic deformation following the 2024 Noto Peninsula earthquake (M7.6), which occurred on January 1, 2024, in the Noto Peninsula, Japan. The observed postseismic deformation for 10 months after the earthquake indicated that the magnitude of the horizontal deformation near the fault (Noto Peninsula) and farther away (Niigata Prefecture and Toyama Prefecture) was nearly the same, ranging from 2 to 4 cm toward the northwest. Regarding vertical deformation, subsidence of several centimeters was observed in the Noto Peninsula, while uplift of a few centimeters was observed from Niigata Prefecture to Toyama Prefecture. No single mechanism, poroelastic rebound, afterslip, or viscoelastic relaxation, could explain all the observed deformations. The key to understanding multiple mechanisms lied in the vertical deformation particularly, the deformation at the Hegura Island station, the only station located northwest of the focal region. Based on the constraint that the Hegura Island station subsides, we constrained the parameters governing viscoelastic relaxation and then estimated afterslip based on the data that removed the deformation caused by viscoelastic relaxation. This approach allowed us to explain the observed horizontal and vertical deformations. The estimated optimal thickness of the elastic layer and viscosity were 40 km and 4 × 10 18  Pa·s, respectively. Afterslip was estimated in the northern part of the Noto Peninsula. The postseismic deformation for 10 months after the earthquake was dominated by viscoelastic relaxation, and the effects of the afterslip were confined to the northern part of the Noto Peninsula. The slip distribution differed significantly when considering only afterslip compared to when considering multiple mechanisms. Focusing on a single mechanism can lead to misinterpretations. Finally, since postseismic deformation of several mm/yr is expected to continue for decades or longer, it must be remembered that postseismic deformation is included in the monitoring of crustal deformation in this region. Graphical Abstract