On 4 and 6 July 2019, two large strike‐slip earthquakes with W‐phase moment magnitudes MWW 6.5 (foreshock) and MWW 7.1 (mainshock) struck the Eastern California Shear Zone, northeast of Ridgecrest. The faulting geometry and kinematic coseismic slip distribution of both events are determined by jointly inverting seismological and geodetic observations guided by aftershock and surface rupture locations. The foreshock ruptured two orthogonal faults with a prominent L‐shaped geometry with maximum slip of ~1.1 m on the NE‐SW segment. The mainshock faulting extended NW‐SE along several primary fault segments that straddle the foreshock slip. The surface rupture and slip model indicate mostly near‐horizontal strike‐slip motion with maximum slip of ~3.7 m, but there is a localized vertical dip‐slip motion. Both the foreshock and mainshock ruptures terminate in regions of complex surface offsets. High aftershock productivity and low rupture velocity may be the result of rupture of a relatively immature fault system.

The eastern portion of the Shumagin gap along the Alaska Peninsula ruptured in an M W 7.8 thrust earthquake on 22 July 2020. The megathrust fault space-time slip history is determined by joint inversion of regional and teleseismic waveform data along with co-seismic static Global Navigation Satellite System (GNSS) displacements. The rupture expanded westward and along-dip from the hypocenter, located adjacent to the 1938 M W 8.2 Alaska earthquake, with slip and aftershocks extending into the gap about 180 to 205 km, respectively, at depths from 15 to 40 km. The deeper half of~75% of the Shumagin gap experienced faulting. However, the patchy slip is significantly less than possible accumulated slip since the region's last major rupture in 1917, compatible with geodetic seismic-coupling estimates of 10-40% beneath the Shumagin Islands. The rupture terminated in the western region of very low seismic coupling. There was a regional decade-scale decrease in b-value prior to the 2020 event. Plain Language Summary A large M W 7.8 underthrusting earthquake ruptured on the plate boundary between the Pacific and North American Plates along the Alaska Peninsula on 22 July 2020. The fault slipped in the region between large plate boundary earthquakes in 1938 and 1946 that has been called the Shumagin seismic gap. The last major earthquake on this part of the plate boundary occurred in 1917, with both that event and the 2020 earthquake rupturing the eastern half of the Shumagin gap. The slip was concentrated in several patches, with the largest slip patch located directly below the Shumagin Islands. Global Positioning Satellite (GPS) stations on the islands recorded the ground displacement clearly. Using GPS displacements along with seismic wave ground motions recorded by regional strong motion and global broadband stations, the slip space-time history during the faulting is determined. The coseismic slip is significantly less than the amount that could have accumulated from relative plate motions since 1917, which is consistent with geodetic estimates of low seismic coupling on this portion of the plate boundary. There was a regional decrease in the slope (b-value) of the earthquake magnitude distribution over the decade before the event.

For analyzing possible reasons for the heavy damage and seismogenic features of the 24 August 2016 Norcia earthquake, we constructed and analyzed its rupture process by incorporating data sets of near‐field strong‐motion, teleseismic and static GPS displacements. The optimized model revealed a relatively compact slip pattern with mainly normal fault components. The maximum slip was around 0.9 m, while the rupture areas extended ~11 km and ~20 km along dip and strike, respectively. The total seismic moment was 2.3 × 1018 Nm, equivalent to Mw 6.2. Most seismic moments were released within 10 s, radiating 3.5 × 1013 J of seismic energy. The rupture history showed asymmetric propagation and is characterized by a relatively high rupture velocity within the first 6 s with a maximum of ~3.2 km/s. The main shock slip pattern correlated well with the aftershocks distribution, and most of the accumulated strain was released in the east of seismic gap between the nearby 1997 and 2009 earthquake sequences.

Anchorage, Alaska, was strongly shaken on 30 November 2018 by an MW 7.1 earthquake that ruptured within the underthrust Pacific plate at depths of from 45 to 65 km. Ground failures occurred in saturated lowlands filled with sediments, producing notable road damage, but there was limited structural damage in Anchorage, only ~12 km south of the epicenter. The earthquake has a normal faulting geometry with a shallowly dipping east‐west tension axis indicating intraslab deformation, likely between the underthrust Yakutat terrane and adjacent Pacific seafloor. Separate and joint inversions of teleseismic P and SH waves, regional strong ground motions, and GPS static displacements provide a weak preference for a westward steeply dipping rupture plane with up to 2 m of slip distributed over a single slip patch with dimensions of 20 × 20 km. The ~12 s long rupture expanded northward. Aftershocks occur at shallower depths than the mainshock slip zone.