We derive a new earthquake focal mechanism catalog for 86 $Mw>4.0$ earthquakes that occurred in the Myanmar region from 2016 to 2021. We apply the generalized Cut‐and‐Paste inversion method to a new set of regional broadband waveform data to obtain the earthquake focal mechanism and centroid depth with uncertainties estimated in a bootstrapping manner. Compared with global earthquake catalogs, our results are better aligned with mapped, active faults and reveal seismic activity along unmapped, blind faults. Our new catalog shows that the Sagaing Fault is more active in its northern segment with deeper seismogenic zone (∼27 km) compared to its southern segment that has a shallower seismogenic zone (∼10 km), sandwiching a seismic gap in its central segment. Earthquakes that occurred on the unmapped, blind faults beneath the Central Myanmar Basin at shallow depths (3–12 km) suggest a dominating northeast–southwest compressional stress field. Shallow earthquakes beneath the Indo‐Myanmar Range (IMR) are rare, instead, north–south‐oriented strike‐slip faults are active within the deep accretionary wedge or lower crust of the Myanmar plate between depths of 20 and 40 km. At the eastern edge of the IMR, earthquakes with high‐angle thrust mechanisms occurred between depths of 30 and 48 km, likely along steep faults separating the accretionary wedge from the Myanmar forearc crust. High‐resolution intraslab focal mechanisms show that to the north of 22° N, slab deformation is dominated by strike‐slip earthquakes with subvertical fault planes down to a depth of ∼25 km beneath the slab, suggesting lateral shear within the slab due to the northward motion of the Indian plate. To the south, more normal‐faulting earthquakes suggest a stronger role of plate‐bending processes in the slab deformation.

We use ambient‐noise tomography to map regional differences in crustal Rayleigh‐wave group velocities with periods of 8–40 s across north Tibet using the International Deep Profiling of Tibet and the Himalaya phase IV arrays (132 stations, deployed for 10–24 months). For periods of 8–24 s (sensitive to midcrustal depths of ~5–30 km), we observe striking velocity changes across the Bangong‐Nujiang and Jinsha suture zones as well as the Kunlun‐Qaidam boundary. From south to north, we see higher velocities beneath the Lhasa terrane, lower velocities beneath the Qiangtang, higher velocities in the Songpan‐Ganzi and Kunlun terranes, and the lowest velocities beneath the Qaidam Basin. Maps at periods of 34 and 40 s (sensitive to the middle and lower crust at depths of ~30–60 km) do not show evidence of changes across those boundaries. Any differences between the Tibetan terrane lower crusts that were present at accretion have been erased or displaced by Cenozoic processes and replaced almost ubiquitously by uniformly low velocities.

We present tomographic models of frequency-dependent Lg and Sn attenuation in eastern Mongolia using data from 228 local earthquakes that were recorded by 69 broad-band seismic stations. We adopt the two-station method (TSM) and reverse two-station method (RTM) to measure the frequency-dependent Sn and Lg Q values, respectively. The RTM has the advantage of allowing us to make attenuation measurements that are independent of site effects, instrument responses and source parameters. We have tomographically mapped Lg Q and η in order to understand spatial variations in crustal attenuation across eastern Mongolia and the surrounding regions. High Lg attenuation and low η are found in the volcanic region of the Middle Gobi Desert, while high Lg attenuation and high η are found in and around the tectonically active regions of the South Gobi Desert. We have also examined uppermost mantle attenuation by mapping the variation in Sn attenuation and η values. Regions of high Sn attenuation are found in the mountainous and volcanically active regions of the Middle Gobi Desert. Our Lg and Sn attenuation models correlate well with lateral variations in velocity as well as with the major tectonic units that make up eastern Mongolia. High attenuation regions seem to be associated with low velocities, Quaternary volcanoes and Cenozoic tectonic activity.