Aleutian Trench in the context of "Kuril–Kamchatka Trench"

The Hawaiian–Emperor seamount chain is a mostly undersea mountain range in the Pacific Ocean that reaches above sea level in Hawaii. It is composed of the Hawaiian ridge, consisting of the islands of the Hawaiian chain northwest to Kure Atoll, and the Emperor Seamounts: together they form a vast underwater mountain region of islands and intervening seamounts, atolls, shallows, banks and reefs along a line trending southeast to northwest beneath the northern Pacific Ocean. The seamount chain, containing over 80 identified undersea volcanoes, stretches about 6,200 km (3,900 mi) from near the Aleutian Trench off the coast of the Kamchatka peninsula in the far northwest Pacific to the Kamaʻehuakanaloa Seamount (formerly Lōʻihi), the youngest volcano in the chain, which lies about 35 kilometres (22 mi) southeast of the Island of Hawaiʻi.

The Hawaiʻi hotspot is a volcanic hotspot located near the namesake Hawaiian Islands, in the northern Pacific Ocean. One of the best known and intensively studied hotspots in the world, the Hawaii plume is responsible for the creation of the Hawaiian–Emperor seamount chain, a 6,200-kilometer (3,900 mi) mostly undersea volcanic mountain range. Four of these volcanoes are active, two are dormant; more than 123 are extinct, most now preserved as atolls or seamounts. The chain extends from south of the island of Hawaiʻi to the edge of the Aleutian Trench, near the eastern coast of Russia.

While some volcanoes are created by geologic processes near tectonic plate convergence and subduction zones, the Hawaiʻi hotspot is located far from plate boundaries. The classic hotspot theory, first proposed in 1963 by John Tuzo Wilson, proposes that a single, fixed mantle plume builds volcanoes that are then cut off from their source by the movement of the Pacific plate. This causes less lava to erupt from these volcanoes and they eventually erode below sea level over millions of years. According to this theory, the nearly 60° bend where the Emperor and Hawaiian segments within the seamounts was caused by shift in the movement of the Pacific Plate. Studies on tectonic movement have shown that several plates have changed their direction of plate movement because of differential subduction rates, breaking off of suducting slabs, and drag forces. In 2003, new investigations of this irregularity led to the proposal of a mobile hotspot hypothesis, suggesting that hotspots are prone to movement instead of the previous idea that hotspots are fixed in place, and that the 47-million-year-old bend was caused by a shift in the hotspot's motion rather than the plate's. According to this 2003 study, this could occur through plume drag taking parts of the plume in the direction of plate movement while the main plume could remain stationary. Many other hot spot tracks move in almost parallel so current thinking is a combination of these ideas.

The Aleutian Arc is a large volcanic arc in the U.S. state of Alaska. It consists of a number of active and dormant volcanoes that have formed as a result of the subduction of the Pacific plate beneath the North American plate along the Aleutian Trench. Although taking its name from the Aleutian Islands, this term is a geologic grouping rather than a geographic one. The Aleutian Arc extends through the Alaska Peninsula following the Aleutian Range through the Aleutian Islands. The arc makes up a sizable portion of the Pacific Ring of Fire, and is known for generating many strong magnitude earthquakes (magnitude 6–6.7) as well as its volcanism.

The Ulakhan Fault is a left-lateral transform fault that runs along the boundary between the North American plate and the Okhotsk microplate in northeast Asia. It runs from a triple junction in the Chersky Range in the west, to another triple junction with the Aleutian Trench and the Kuril Trench in the east. From the offset of dated geomorphological features, a slip rate of 5.3±1.3 mm per year has been measured, consistent with estimates from GPS-constrained global plate models. The analysis of fault scarps along the fault zone in the Seymchan Basin suggests that the fault is characterised by occasional large (M_w>7.5) earthquakes.

Oblique subduction is a form of subduction (i.e. a tectonic process involving the convergence of two plates where the denser plate descends into Earth's interior) for which the convergence direction differs from 90° to the plate boundary. Most convergent boundaries involve oblique subduction, particularly in the Ring of Fire including the Ryukyu, Aleutian, Central America and Chile subduction zones. In general, the obliquity angle is between 15° and 30°. Subduction zones with high obliquity angles include Sunda trench (ca. 60°) and Ryukyu arc (ca. 50°).

Obliquity in plate convergence causes differences in dipping angle and subduction velocity along the plate boundary. Tectonic processes including slab roll-back, trench retreat (i.e. a tectonic response to the process of slab roll-back that moves the trench seaward) and slab fold (i.e. buckling of subducting slab due to phase transition) may also occur.