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Bungo Channel

The Bungo Channel (豊後水道, Bungo-suidō) is a in southwestern that separates the islands of and while connecting the to the , a marginal sea of the . It measures approximately 100 kilometers in length and 50 kilometers in width at its broadest point, narrowing to about 17 kilometers at the Hōyo Strait section, with a mean water depth of 80 meters across a relatively flat shelf bottom ranging from 60 to 100 meters. The channel's oceanography is dominated by the intrusion of the warm , which drives gravitational circulation patterns including southward surface flows and northward bottom intrusions of nutrient-rich cold water, alongside tidal influences and semidiurnal internal tides that can intensify periodically. These dynamics support a highly productive , including spawning grounds for commercially vital such as Japanese jack mackerel (Trachurus japonicus), (Pagrus major), and (Seriola quinqueradiata), as well as unique habitats like beds covering 2.2 square kilometers in adjacent coastal areas. Geologically, the Bungo Channel formed during the epoch through phases of erosion, tidal sandbank development, and deposition, and it lies in a tectonically active zone above the where the subducts beneath the , resulting in frequent earthquakes such as the M5.0 event in 2017 and the M6.4 quake on April 17, 2024. As a vital navigational route since at least the era, it facilitates maritime trade and supports key ports like Oita and Uwajima, underscoring its economic significance in Japan's coastal commerce and fisheries.

Geography

Location and Extent

The Bungo Channel is a situated in southwestern , separating the island of from the island of and serving as a key geographical link in the region's system. It lies exclusively within the of , with no shared boundaries with other countries. The channel's position is officially recorded in Japan's geographical at approximately 33°10′ N, 132°07′ E, encompassing a area that extends roughly from this central point. The strait specifically demarcates the boundary between Ōita Prefecture on the western (Kyushu) side and Ehime Prefecture on the eastern (Shikoku) side, forming a natural divide along their coastal margins. To the east, it connects directly to the Seto Inland Sea via the Hōyo Strait, which marks the channel's narrowest entrance and facilitates maritime passage into the broader inland waters. Toward the west and south, the Bungo Channel opens into the Philippine Sea, a marginal sea of the western Pacific Ocean, influencing regional coastal dynamics without extending into international waters. Prominent nearby settlements highlight the channel's role in local geography, including the city of Ōita on the northern Ōita Prefecture coast facing the channel's broader expanse, Uwajima on the Ehime Prefecture shoreline along the eastern boundary, and Seiyo further inland but proximate to the Shikoku coastal zone. At the western end, Sukumo in Kōchi Prefecture borders the channel's outlet to the Philippine Sea, underscoring its integration with surrounding peninsular features.

Physical Features

The Bungo Channel measures approximately 100 km in length from east to west, with widths varying from a minimum of 14 km at the Hōyo Strait to broader expanses reaching up to 50 km in other sections. This configuration creates a dynamic connecting the to the , bordered by the islands of and . The channel's overall structure supports significant water exchange, influenced by its elongated form and varying constriction points. The coastline surrounding the Bungo Channel is complex and irregular, characterized by indented bays such as Usuki Bay on the side and prominent headlands including the Sadamisaki Peninsula that defines the Hōyo Strait. These features result in a highly varied shoreline that includes sheltered inlets and exposed promontories, contributing to diverse coastal habitats and patterns. The seabed reflects this topographic complexity, featuring tidally influenced elements like scour holes, tidal sandbanks, and depositional dunes, with substrates transitioning between rocky outcrops near headlands and sandy expanses in bay areas. Bathymetric profiles in the channel show shallow coastal zones along the margins, gradually deepening to the main navigational axis, where depths range from 60 m in peripheral areas to a maximum of around 100 m in central portions. This profile supports a mix of substrates, with rocky bottoms prevalent in deeper, high-current zones and sandy sediments dominating shallower, depositional environments. The region's , with summer highs averaging up to 30°C and winter lows around 10°C, modulates these physical features through seasonal variations in energy and , promoting sediment redistribution and coastal reshaping.

Geology

Formation and Evolution

The Bungo Channel, as part of the broader system, originated during the through tectonic processes that included regional uplift in surrounding areas of southwest , followed by in the basin, which facilitated subsequent sediment deposition and marine incursion. During the around 20,000 years ago, low sea levels exposed the area as land with river systems draining into the Pacific, setting the stage for the marine . This transition marked the key geological shift from terrestrial to marine environments, with the beginning to form through seawater invasion approximately 11,000 years ago. The modern configuration of the Bungo Channel developed primarily during the Holocene Epoch, driven by post-glacial sea-level rise between approximately 10,000 and 6,000 years ago, which reshaped the strait through erosion and deposition. This period involved three distinct phases: an initial erosional phase at lowstand, where an erosional surface formed overlain by dune-covered sand banks; a transgressive phase with rising sea levels that amplified tidal energy, creating scour holes and developing tidal sand banks over a ravinement surface; and a highstand phase where stabilized sea levels reduced tidal currents, leading to the deposition of stabilizing dunes influenced by the . These processes were modulated by ongoing tectonic in the basin at rates of 0.09–0.23 mm per year, which accommodated sediment infilling from surrounding fluvial and coastal sources. By around 8,000 years ago, the current strait configuration was largely established, with the Bungo Channel serving as a critical outlet for the , its tidal sand bodies reflecting the interplay of , sediment dynamics, and basin subsidence. The resulting features a sequence of Pleistocene to strata dominated by offshore tidal sands, illustrating the channel's evolution from an erosional conduit to a depositional feature within Japan's complex tectonic framework.

Tectonic Activity

The Bungo Channel lies along the Nankai Trough subduction zone, where the Philippine Sea Plate subducts beneath the Eurasian Plate at a rate of 4.1–6.5 cm per year. This oblique subduction drives ongoing tectonic deformation in the region, contributing to the channel's dynamic geophysical setting. The area is characterized by recurrent long-term slow slip events (SSEs) on the plate interface, with well-documented occurrences in 1996–1997, 2003, 2010, 2018–2019, and a Mw 6.0 event starting in late 2023. These events involve aseismic slip magnitudes of up to 20–30 cm, primarily in the down-dip transition zone of the megathrust, and are detected through continuous GNSS observations, leveling surveys, tide gauge records, and associated seismic tremor activity. The SSEs recur approximately every 5–8 years, releasing stress without generating significant seismic waves, as observed through 2025. These slow slip processes are linked to the broader seismic hazard of the Nankai Trough, which has produced megathrust earthquakes of magnitude 8 or greater at intervals of 100–150 years. The most recent major event was the 1946 Nankai earthquake (Mw 8.1), which ruptured segments adjacent to the Bungo Channel and highlighted the potential for future large-scale failures in this locked zone. Recent seismicity includes a M6.4 earthquake on April 17, 2024, beneath the Bungo Channel and a M7.1 event on August 8, 2024, in adjacent Hyuga-nada, the latter preceded by the late 2023 SSE and prompting a temporary megaquake advisory that was lifted on August 15, 2024. Volcanic activity from the adjacent Southwest Japan volcanic arc supplies substantial sediment to the , including dispersed volcanic ash that forms a key component of the incoming accretionary material influencing the Bungo Channel's tectonic framework.

Oceanography

Currents and Circulation

The Bungo Channel exhibits a complex hydrodynamic regime dominated by the Kyucho , a periodic intrusion of warm from the Pacific into the channel. This swift flows northward, with typical speeds of approximately 50 cm/s and occasional peaks reaching 60–70 cm/s, influenced by the channel's coastal and bays that temporarily store warm before further propagation. The Kyucho is particularly driven by density gradients, peaking during summer months such as July and August when enhances the intrusion, while it weakens in winter due to increased vertical mixing that homogenizes masses. The broader circulation in the Bungo Channel features a bidirectional flow pattern, characterized by gravitational circulation where low-density surface waters outflow southward toward the Pacific Ocean, and high-density bottom waters inflow northward from the Pacific. This pattern is primarily forced by tidal asymmetries and seasonal wind variations, with tidal currents promoting vertical mixing and wind enhancing surface advection. The Kuroshio Current, the Pacific's western boundary current with speeds ranging from 50 to 300 cm/s, significantly influences this regime through sporadic intrusions and the formation of anticyclonic eddies, which sharpen frontal waves and facilitate enhanced cross-shelf exchange between the open ocean and the channel. These eddies, propagating southward along Japan every 45–180 days, intensify Kyucho events primarily from spring to autumn, promoting nutrient uplift and water mass renewal.

Tidal Patterns

The Bungo Channel exhibits a mixed semidiurnal regime, featuring two unequal high and two unequal low each , primarily driven by the semidiurnal (principal lunar) and (principal solar) constituents. The constituent dominates, with observed amplitudes around 1.0 m in the region, contributing to the overall dynamics. Tidal ranges vary spatially across the channel, measuring approximately 1-2 m at the southern mouth near locations like Saiki, where high tides reach up to 1.7 m and low tides around 0.2 m during conditions. In the narrower northern portions, including the Hōyo Strait—the most constricted section at about 14 km wide—the range amplifies to 2-3 m due to funneling effects that concentrate tidal energy as the channel narrows between the Sadamisaki Peninsula and Oita Prefecture coastline. At stations like Yawatahama near the strait, maximum high tides can exceed 2.4 m, with minimum lows near 0 m, reflecting this amplification. The tidal cycle aligns with the of roughly 12.4 hours, producing semidiurnal oscillations, while fortnightly spring-neap variations arise from the alignment of and phases; spring yield ranges up to 3.4 m and stronger flows, whereas neap reduce them to about 0.8 m. These variations are evident in observed data, where and amplitudes combine constructively during springs to enhance differences. Resonance interactions with the Seto Inland Sea amplify tidal currents within the channel, as progressive waves entering via the Bungo propagate northward and encounter standing waves in the inland sea's central basin, intensifying oscillatory flows particularly in constricted areas like the Hōyo Strait.

Ecology

Biodiversity

The Bungo Channel supports a rich marine biodiversity, with hundreds of species of aquatic plants and animals documented in its waters and the adjacent . This diversity is driven by the channel's dynamic oceanographic conditions, including strong tidal currents and nutrient-rich inflows from the , fostering habitats for a variety of fish, invertebrates, and marine mammals. Key fish species include the Japanese jack mackerel (Trachurus japonicus), which forms significant populations influenced by subsurface temperature variations, the (Trichiurus japonicus), a commercially important species with seasonal spawning broods, and the (Plecoglossus altivelis), an amphidromous species common in the adjacent . Invertebrates thrive in the channel's varied substrates, with notable examples including horseshoe crabs (Tachypleus tridentatus), which inhabit coastal areas of the adjacent , and pearl oysters (Pinctada fucata), valued for their cultured pearls in nearby bays. Marine mammals such as the (Neophocaena phocaenoides), with populations migrating through the channel into the , and occasional sightings of whales like the (Globicephala macrorhynchus) during cruises, add to the ecological complexity. Distinct habitats enhance this biodiversity, including deep spawning grounds in the Hōyo Strait, where Japanese jack mackerel and reproduce, particularly during spring and autumn peaks. Coastal forests, dominated by Ecklonia species along peninsulas like Sata-Misaki, provide shelter and foraging areas for and . Sandy bays support blooms, with species like Nemopilema nomurai appearing seasonally in adjacent Iyo-Nada waters connected to the channel. Migratory patterns of pelagic species, such as and , are heavily influenced by the channel's currents, leading to seasonal influxes that boost local productivity. Notable adaptations among residents include local stocks of (Trichiurus japonicus), which exhibit distinct seasonal broods tied to tidal and temperature cycles in the Bungo Channel, supporting targeted fisheries.

Conservation Challenges

The Bungo Channel faces significant pollution pressures from multiple sources, primarily industrial effluents discharged from Ōita ports, which include petrochemical and manufacturing waste that degrade water quality through heavy metals and organic compounds. Agricultural runoff, carrying pesticides such as and simetryn from surrounding rice paddies and orchards via rivers like the Ono and Ban'ya, contributes to in marine organisms, posing health risks to species like . Additionally, plastic debris, including transported from the broader , accumulates in coastal zones, with standing stocks of marine litter, including plastics, estimated at approximately 3,400 tons in the Seto Inland Sea. Overfishing and associated loss have led to notable declines in key populations in the Bungo Channel. Commercial harvesting has reduced pearl oyster (Pinctada fucata) numbers, compounded by mass mortality events linked to environmental stressors, while incidental capture and degradation from coastal development have decimated (Tachypleus tridentatus) populations in the adjacent , with up to 80% of spawning grounds lost since the mid-20th century. Kyucho events—sudden warm water intrusions from the —further stress temperate by elevating temperatures by 4–5°C, altering s and favoring subtropical invaders over native biota. Climate change amplifies these threats, with sea surface temperatures in the region rising by approximately 0.5–0.7°C since the 1980s, driving species range shifts and increasing the frequency of events in stratified waters of the . Bottom water warming trends of 1.5°C per century in the Bungo Channel have been documented through foraminiferal proxies, correlating with reduced oxygen and expanded low-oxygen zones that threaten benthic communities. Conservation efforts include the designation of marine protected areas along the Bungo Channel, such as coastal zones near Cape Kamato and Cape Tsurumi in , aimed at restricting fishing and habitat alteration. The Japan's Ministry of the Environment oversees monitoring programs to track and , integrated into national strategies under the Nature Conservation Law. Broader initiatives stem from the Law on Special Measures for Environmental Protection of the , which enforces total pollutant load controls and fosters regional cooperation, with international dimensions through frameworks like the International Center for Environmental Management of Enclosed Coastal Seas.

History

Pre-Modern Period

The Bungo Channel region exhibits evidence of early human activity from the (c. 300 BCE–300 CE), when continental immigrants introduced wet-rice agriculture, and iron , and settled village life to northern . Archaeological excavations in Ōita Prefecture, adjacent to the channel, have uncovered remains of pit dwellings, storage facilities, and burial sites indicative of these communities, with the channel serving as both a natural barrier separating from and a conduit for coastal trade along the Pacific seaboard. Sites like the Ankokuji Village Ruins in the Kunisaki area demonstrate how local populations adapted to the maritime environment, utilizing the strait for fishing and early exchange networks that connected inland farming villages to broader regional interactions. In the medieval era, spanning the Kamakura (1185–1333) and Muromachi (1336–1573) periods, the Bungo Channel's strategic position amplified its involvement in naval conflicts and piracy. The strait facilitated maritime warfare among feudal lords vying for control of Kyushu's resources, while wako pirates—often ronin samurai and coastal raiders—exploited the channel's currents for hit-and-run attacks on Korean and Chinese coasts, as well as domestic targets. These activities peaked in the 14th–16th centuries amid political instability, with pirate fleets using hidden coves along the channel for resupply and evasion, contributing to the shogunate's efforts to regulate sea lanes through edicts against unauthorized voyages. The Otomo clan, dominant in the region during the late Muromachi period, fortified coastal positions to counter such threats, underscoring the channel's role in the turbulent transition to the Sengoku era. During the (1603–1868), the transformed ports along the Bungo Channel into regulated trading hubs under isolation policies, emphasizing domestic coastal commerce while restricting foreign access. Usuki, a key port on the channel's eastern shore, emerged as a vital outpost for rice, salt, and regional goods transport, with its castle serving as the administrative center for the Usuki Domain under Inaba clan oversight. The 1600 arrival of the Dutch vessel Liefde in Usuki Bay, which carried English navigator William Adams and influenced Tokugawa Ieyasu's shipbuilding and trade initiatives, highlighted the port's early role in limited European contacts before stricter controls were imposed. This era saw the channel support stable mercantile networks, though naval patrols enforced limits on open-ocean voyages to prevent smuggling or unrest. Archaeological discoveries in the region reveal a rich tapestry of pre-modern maritime heritage, including remnants of coastal fortifications and potential sites tied to and . Excavations at Usuki Castle ruins have yielded stone walls, moats, and artifacts from the 16th-century construction by Otomo Sorin, illustrating defensive adaptations to the channel's tidal dynamics during the late Muromachi and early transitions. Further finds, such as and tools from Yayoi settlements and scattered medieval anchors or fragments along the strait, attest to centuries of navigational challenges and economic activity, though systematic underwater surveys remain limited. These artifacts underscore the channel's enduring function as a contested shaping local defenses and livelihoods.

20th Century and Beyond

During , the Bungo Channel emerged as a critical strategic naval passage for the , facilitating movements between the and the . In 1944, it became a focal point for U.S. operations, including patrols and attacks on Japanese convoys and warships transiting the ; for instance, submarines such as USS Sturgeon and USS Besugo engaged targets in the eastern approaches to the channel. A pivotal event occurred on November 29, 1944, when USS Archerfish sank the in the en route to the via the Bungo Channel, approximately 55 miles southeast of Shiono-misaki, marking the largest warship sunk by a in history. These wartime submarine engagements in the Bungo Strait inspired Commander Edward L. Beach's 1955 novel , which was adapted into a 1958 film starring and , depicting intense undersea combat in the area. In the post-war era, the Bungo Channel region underwent rapid industrialization, driven by Japan's economic recovery. Port facilities in Ōita expanded significantly from the 1950s through the 1970s to support , with the establishment of the Ōita Petrochemical Complex in 1969 transforming the area into a key hub for production and chemical manufacturing. This development leveraged the channel's maritime access for raw material imports and product exports, contributing to national growth in sectors. From the to the , intensified seismic monitoring in the Bungo Channel focused on slow slip events along the zone, facilitated by Japan's GEONET GPS network operational since ; these efforts detected repetitive long-term slow slips, providing data on interplate coupling and earthquake precursors. The exerted only minor effects on the Bungo Channel, as waves propagating from the Pacific were significantly attenuated through coastal straits, resulting in displacements under 1 meter in the region. Into the , infrastructure initiatives have included proposals for a major across the Hōyo Strait section of the Bungo Channel to link and Kyūshū, with joint research by Ōita and Ehime prefectures beginning in 1995 and feasibility studies confirming technical viability by 1998, though construction remains pending. The Law Concerning Special Measures for Conservation of the Environment of the , enacted in 1973 and amended in 2015, imposes controls on industrial effluents and coastal development to safeguard and in the channel area. On April 17, 2024, a 6.4 struck the Bungo Channel, with its at 33.2°N, 132.4°E and depth of 50 km, causing shaking in Ehime and prefectures but no major damage or .

Economy and Navigation

Maritime Trade

The Bungo Channel serves as a vital maritime corridor connecting the ports of the , such as those in and , with international shipping lanes in the . This strategic position facilitates the transit of coastal cargo vessels, including those originating from and ports, enabling efficient regional and trans-Pacific flows. Key ports bordering the channel include Ōita on the Kyushu coast, a major hub for bulk carriers and exports, supported by its deep-water facilities that accommodate some of the world's largest vessels. The port handles significant volumes of tankers and dry bulk shipments, anchoring Kyushu's primary petroleum refining complex and serving the industrial needs of southwestern . Uwajima, on the Shikoku side, functions as an important facility for ferry services linking and , alongside coastal cargo handling for regional distribution. Navigation in the channel is aided by a network of lighthouses, buoys, and a designed to manage high vessel density and mitigate risks from the powerful Kyucho tidal current, which can reach speeds of up to 6 knots (300 cm/s) and create hazardous conditions for shipping. These measures, including surveillance and designated lanes, ensure orderly for thousands of vessels calling at nearby ports annually. Maritime trade through the Bungo Channel bolsters the economies of and by supporting industrial exports, particularly products from Ōita, and providing essential inter-island connectivity for passengers and goods. This activity underpins regional and , contributing to sustained in the area through reliable access to domestic and Asian markets.

Fisheries and Aquaculture

The Bungo Channel sustains a robust coastal fisheries sector, with primary catches centered on hairtail (Trichiurus japonicus, also known as ) and (Trachurus japonicus, locally called aji). These species benefit from the channel's nutrient-rich currents, which support seasonal migrations and spawning, particularly in the adjacent Hōyo Strait. The region's fisheries fleets, operating from ports in Oita and Ehime prefectures, target hairtail during its dual spring and autumn spawning peaks, while is harvested year-round with peaks in summer. Annual yields from the Bungo Channel area contribute substantially to national totals, with the region accounting for 30–40% of Japan's hairtail catch, estimated at approximately 7,000 tons nationwide as of 2023. catches, including the premium Seki aji variety, add to the overall production, though exact channel-specific figures vary with environmental conditions like influences. These fisheries emphasize sustainable practices amid declining stocks, as noted in transdisciplinary co-management efforts involving local fishers and authorities. Aquaculture operations complement wild capture, focusing on pearl oyster (Pinctada fucata martensii) farming in sheltered bays such as Uchiumi Bay on the channel's eastern (Ehime) side, despite recent mass mortalities affecting production in 2024. Introduced in the late around 1907, this industry produces high-value Akoya pearls, with holding a 90% share of Japan's domestic mother-of-pearl oyster production. Oysters are suspended in nutrient-abundant waters to promote shell growth, influenced by seasonal levels and temperatures averaging 20–25°C. Traditional and modern fishing methods exploit the channel's swift tidal currents, reaching up to 5 knots. Hairtail is primarily caught using trolling lines from small vessels under 5 gross tons, allowing selective harvesting of high-quality fish, while employs purse seine nets and set nets in shallower coastal areas. These techniques align with seasonal patterns, such as increased effort during hairtail spawning seasons to maximize yields without . The sector drives local economies in Uwajima (Ehime) and Oita (Oita Prefecture), employing thousands in , processing, and amid a national decline in fisher numbers. It bolsters Japan's exports, with products like Seki aji and Akoya pearls generating high due to their and recognition. measures, including stock assessments, help sustain these activities against challenges like reductions.

Cultural Significance

Role in Local Culture

The Bungo Channel profoundly shapes the traditions and daily life of coastal communities in Ehime and Oita prefectures, serving as a vital link between and islands. Local festivals and rites reflect the channel's maritime heritage, with events timed to the tidal cycles of the Kyucho current, which can reach speeds of 0.3–0.5 m/s (about ). In Uwajima, a major port city on the side, annual celebrations like the Warei Taisai ( Festival) in late July draw thousands to honor local deities and purify the community, incorporating parades and fireworks. Similarly, on the side, the Himeshima Fish Festival in May celebrates the channel's bounty with tastings and boat parades, praying for abundant catches from the nutrient-rich waters. Folklore in the Bungo Channel region draws from broader tales of sea spirits believed to influence maritime conditions, creating both peril and plenty for fishermen. These legends, passed down through oral traditions and local , reflect the respect demanded by the . Such myths appear in and , evoking the channel's unpredictable power to symbolize human resilience against nature's forces. The channel's ferries strengthen community bonds across the strait, enabling regular island-hopping and social ties between and residents who share similar seafaring . Services like the Orange Ferry, operating multiple daily routes between Yawatahama Port in Ehime and Oita Port, carry passengers and cargo while promoting cultural exchanges through onboard events and scenic views of the , helping maintain familial and economic connections in isolated coastal areas. This connectivity supports a lifestyle centered on the , where residents from towns like Saganoseki and Uwajima collaborate on joint fishing initiatives and seasonal migrations. Culinary traditions highlight the channel's ecological richness, with dishes featuring harvested from its plankton-abundant waters. In Uwajima, tai-meshi—sliced raw sea bream () dipped in a of , , and , served over steamed rice—originated as a fisherman's using fresh catches from the Bungo Channel, symbolizing prosperity due to the fish's auspicious name and vibrant color. This specialty, often prepared with farmed or wild tai raised in the channel's calm bays, underscores the region's reliance on sustainable , where the mixing currents foster high-quality, firm-textured fish prized nationwide.

Representation in Media

The Bungo Channel features prominently in Edward L. Beach Jr.'s 1955 novel Run Silent, Run Deep, where it serves as a key setting for intense submarine warfare, underscoring its strategic naval importance during World War II as a heavily patrolled Japanese waterway. The narrative draws from Beach's own experiences as a U.S. Navy submarine commander, portraying the channel as a treacherous zone fraught with ambushes and depth-charge attacks. This literary depiction was adapted into the 1958 film , directed by and starring and , which amplifies the channel's role as a perilous hunting ground for American submarines evading Japanese destroyers. The film's plot centers on a commander's obsessive quest for revenge in the Bungo Strait, reflecting real U.S. operations in 1943–1944, when the area—nicknamed after the notorious "Bungo Pete" patrol—claimed several Allied vessels through coordinated anti-submarine efforts. In modern Japanese media, the Bungo Channel appears as a dramatic coastal backdrop in kaiju films, notably the 1995 Toho production Godzilla vs. Destoroyah, where Godzilla emerges at its mouth en route to a nuclear facility, leading to a climactic freezing sequence that highlights the strait’s isolating geography. Adaptations in manga, such as those tied to the Godzilla franchise, similarly use the channel for high-stakes monster confrontations, emphasizing its position as a volatile maritime threshold. Documentaries on the Nankai Trough's tectonic risks frequently reference the Bungo Channel due to its proximity to zones and of tsunami impacts, as explored in geological surveys linking it to major seismic events like the 1707 Hōei earthquake. These productions, often produced by outlets like , portray the strait not only as a geological hotspot but also as a site of potential catastrophe, reinforcing its media role in narratives of natural peril. Across these representations, the Bungo Channel symbolizes a space—a boundary between the sheltered and the open Pacific—evoking themes of transition, danger, and confrontation in both wartime and disaster contexts.