Rapa Nui

Rapa Nui, known to Europeans as Easter Island, is a 164-square-kilometer volcanic island in the southeastern Pacific Ocean, situated approximately 3,700 kilometers west of Chile and over 2,000 kilometers from its nearest inhabited neighbor, Pitcairn Island. It is the most geographically isolated permanently inhabited island on Earth. Formed by three shield volcanoes—Poike, Rano Kau, and Terevaka—the island rises from the East Pacific Rise at roughly 27° south latitude and 109° west longitude, a position that placed it at the extreme eastern margin of the Polynesian world. Despite its small size and remoteness, Rapa Nui became the setting for one of the most culturally productive and scientifically debated societies in the Pacific, producing monumental stone architecture, a unique script, and an elaborate ritual system that have fascinated scholars since European contact in 1722.

The island's modern prominence in popular culture derives largely from its approximately 1,000 monolithic statues, the moai, which were carved from compressed volcanic tuff and erected on stone platforms along the coastline. But Rapa Nui's significance extends well beyond its statuary. The island has become a contested case study in environmental history, with competing narratives attributing its transformation to self-inflicted ecological collapse, to the synergistic effects of introduced rats and climate change, or to the devastation wrought by European contact, slave raids, and epidemic disease. Disentangling these narratives requires careful attention to radiocarbon chronology, paleoecological evidence, ancient DNA, and the material record of a society that adapted to profound isolation with remarkable ingenuity.

Colonization and chronology

The question of when Polynesian voyagers first reached Rapa Nui has been revised substantially over the past two decades. Earlier archaeological interpretations, based on now-questionable radiocarbon dates from the site of Anakena on the island's north coast, placed initial settlement as early as 400 CE or even earlier. This long chronology implied centuries of gradual population growth and environmental transformation before the period of intensive moai construction. However, a critical reassessment of the island's radiocarbon record by Terry Hunt and Carl Lipo, published in 2006, demonstrated that the earliest reliable dates from Anakena cluster around 1200 CE, suggesting a colonization date roughly 800 years later than previously assumed.¹

This revised chronology aligns with the broader pattern of East Polynesian settlement established by high-precision radiocarbon dating across the region. A meta-analysis of 1,434 radiocarbon dates from East Polynesia, published in 2011, showed that the colonization of this vast area occurred in two phases: an initial settlement of the Society Islands around 1025–1120 CE, followed after a pause of roughly 70 to 265 years by a rapid dispersal pulse that brought settlers to all remaining islands—including Rapa Nui, Hawai'i, and New Zealand—between approximately 1190 and 1290 CE.² An island-wide assessment of radiocarbon data specific to Rapa Nui, incorporating dates from habitation sites, agricultural features, and monumental architecture, corroborates initial settlement no earlier than the late twelfth or early thirteenth century.¹⁶

The compressed chronology carries profound implications. If colonization occurred around 1200 CE rather than 400 CE, then the entire sequence of forest clearance, moai construction, ahu building, and sociopolitical development unfolded within roughly five centuries rather than thirteen. The Rapanui achievement in monumental architecture appears all the more remarkable for having been compressed into a shorter timeframe, but the narrative of gradual environmental degradation spanning a millennium becomes untenable. Substantial ecological impacts and major cultural investments in statuary began soon after settlement, not after centuries of slow buildup.¹

The moai and Rano Raraku

The moai are monolithic human figures carved predominantly from tuff, a compressed volcanic ash quarried from the interior and exterior slopes of Rano Raraku, a volcanic crater in the eastern part of the island. Approximately 95 percent of all known moai were carved from this single source. The remaining statues were produced from basalt, scoria, and trachyte quarried at other locations. The total corpus comprises roughly 1,000 statues in varying states of completion: some still attached to the quarry bedrock, others standing or lying within the quarry, and still others transported to ahu platforms around the island's perimeter or abandoned along ancient roads.¹⁴

The statues vary enormously in size. The smallest completed moai stand about one meter tall, while the largest erected on an ahu, known as Paro, stands approximately 10 meters high and weighs an estimated 82 tonnes. An even larger unfinished statue, Te Tokanga, remains attached to the Rano Raraku quarry face and would have stood roughly 21 meters tall had it been completed. The typical moai is a stylized male torso with an elongated head, prominent brow ridge, elongated ears, and arms held close to the body with hands resting on the abdomen. Many originally bore cylindrical topknots (pukao) carved from red scoria quarried at Puna Pau, a separate site on the island's western side.¹⁴

Recent research using structure-from-motion photogrammetry with over 11,000 drone images has produced the first comprehensive three-dimensional model of the Rano Raraku quarry, revealing 30 distinct quarrying foci distributed across the crater. Each focus contains redundant production features and employs varied carving techniques, suggesting that moai production was organized at the clan level rather than centrally directed. Multiple workshops operated simultaneously, constrained by natural geological boundaries rather than by hierarchical planning. This decentralized pattern challenges longstanding assumptions that monumental construction necessarily requires centralized political authority.¹⁴

Excavations within Rano Raraku have also revealed that the quarry served a dual purpose. Soil analysis shows that the soils created by quarrying activity—rich in calcium and phosphorus from the weathering of lapilli tuff—were exceptionally fertile. The Rapanui cultivated crops within the quarry itself, and the standing moai that remain embedded in the slopes appear to have been intentionally left in place rather than abandoned mid-transport. The association of moai with agricultural fertility was apparently both symbolic and practical: the statues were believed to promote food production, and the quarry soils genuinely supported intensive horticulture.⁹

Ahu platforms and moai transport

The moai were erected on ahu, stone platforms that served as the ceremonial and mortuary centers of Rapanui communities. More than 300 ahu have been documented around the island's perimeter, though not all supported moai. The largest, Ahu Tongariki, originally held 15 moai on a platform stretching over 100 meters in length. Ahu were typically oriented with their long axis parallel to the coastline, and the moai faced inland, watching over the community's territory rather than gazing out to sea. The platforms incorporated burial chambers, and human remains were interred within or beneath many ahu, linking ancestor veneration to the monumental statuary.⁷

Spatial analysis of ahu locations using point-process modeling has demonstrated a strong correlation between monument placement and the availability of freshwater. Rapa Nui has no permanent streams, and rainfall percolates rapidly through the porous volcanic substrate, emerging at the coast as diffuse seeps where the freshwater lens meets the ocean. These coastal freshwater sources, rather than agricultural gardens or marine resource zones, best predict where ahu were constructed. The finding suggests that ahu functioned not only as ritual centers but as territorial markers for the island's most critical resource.⁷

The question of how the Rapanui transported multi-tonne statues from the Rano Raraku quarry to ahu sites up to 18 kilometers away has generated centuries of speculation. Oral traditions recorded after European contact consistently described the moai as having "walked" to their platforms. Archaeological analysis of the 62 moai found along ancient road networks reveals that these road statues are morphologically distinct from those erected on ahu: they exhibit a pronounced forward lean, a D-shaped base rather than a flat one, and a center of gravity positioned to facilitate a rocking, side-to-side motion when upright. Experimental replications have demonstrated that teams of 18 people, using three ropes to rock a standing moai from side to side while simultaneously pulling it forward, can move a multi-tonne statue at a rate of approximately 100 meters in 40 minutes.⁸

This "walking" transport hypothesis explains several features of the archaeological record that alternative models (dragging on wooden sledges or log rollers) cannot. The distribution of broken road moai shows fracture patterns consistent with tipping during vertical transport rather than falling from horizontal sleds. The roads themselves lack the ruts or compacted surfaces expected from heavy dragging. And the morphological differences between road moai and ahu moai indicate that statues were reshaped after reaching their destination, their bases flattened and their lean corrected for permanent display.⁸

Moai statistics by location^{14, 8}

Sociopolitical organization

Rapanui society was organized around a conical clan system typical of Polynesian chiefdoms, in which hierarchically ranked descent groups traced patrilineal ancestry to a common founding ancestor. The fundamental social unit was the extended family (paenga), which belonged to a lineage (ivi), which in turn formed part of a clan (mata). Oral traditions identify approximately ten major mata on the island, each occupying a defined territorial estate (kainga) that typically extended from the coast into the interior, ensuring each clan access to both marine resources and agricultural land. Boundaries between estates were marked by stone cairns (pipihoreko) and protected by local spirits (akuaku).¹⁰

At the apex of the social hierarchy stood the paramount chief (ariki mau), the senior male in direct patrilineal descent from Hotu Matu'a, the legendary founder of the Rapanui people. The ariki mau was believed to possess mana, sacred power derived from the gods, and his person was surrounded by elaborate taboos. Below the paramount chief, each clan had its own chief and a hierarchy of specialists including priests, master carvers, and warriors. Public works projects, particularly the construction of ahu and the carving and transport of moai, served as the primary economic engines of Rapanui society, mobilizing surplus food production and labor for communal ceremonial purposes.¹⁰

Recent archaeological evidence, however, suggests that the degree of centralized authority may have been overstated by early ethnographers working from post-contact oral traditions that were already fragmentary. The decentralized pattern of moai production at Rano Raraku, with independent clan-based workshops operating simultaneously, implies a political structure in which clans cooperated and competed relatively autonomously rather than under strict hierarchical direction.¹⁴ Analysis of obsidian tools and basalt resources shows communal use of quarry sites across clan boundaries, suggesting that inter-clan relations involved substantial cooperation alongside the competitive statue-building that has received more scholarly attention.¹²

The Birdman cult

At some point, likely in the fifteenth or sixteenth century, a new ritual system emerged on Rapa Nui centered on the annual Tangata Manu (Birdman) competition, which coexisted with and eventually supplanted the moai-centered ceremonial system. The Birdman cult was focused on the volcanic crater of Rano Kau at the island's southwestern tip, where the ceremonial village of Orongo was constructed on the narrow ridge between the crater's interior lake and the sheer ocean cliffs. More than 50 dry-laid stone masonry houses were built at Orongo, arranged in overlapping clusters, and the surrounding rock surfaces were carved with hundreds of petroglyphs depicting birdmen, the fertility deity Makemake, and komari (vulva) symbols.¹⁰

The annual competition required representatives of the island's clans to descend the 300-meter sea cliffs of Rano Kau, swim approximately 1.5 kilometers through shark-infested waters to the offshore islet of Motu Nui, and await the arrival of the sooty tern (manu tara) to lay its first egg of the season. The competitor who secured the first egg and returned it intact to Orongo earned the title of Tangata Manu for his sponsoring chief, who then held ritual authority and certain privileges for the following year. The competition involved considerable physical danger, and deaths from drowning and falling were not uncommon.

The relationship between the Birdman cult and the earlier moai-centered system remains debated. Some scholars have interpreted the transition as evidence of political upheaval—a shift from hereditary chieftainship legitimized by ancestral moai to an annually rotated leadership based on competition. Others see the two systems as complementary rather than sequential, noting that rock art associated with the Birdman cult appears on moai and ahu as well as at Orongo, suggesting overlap rather than replacement. The British archaeologist Katherine Routledge, who conducted fieldwork on the island in 1914–1915, recorded nearly 100 names of Birdman winners directly from informants who had participated in the ceremonies before their suppression by Christian missionaries in the 1860s.

Deforestation and ecological change

When Polynesian settlers arrived, Rapa Nui was covered by a subtropical forest dominated by a now-extinct species of palm closely related to the Chilean wine palm (Jubaea chilensis). Pollen cores extracted from the crater lakes of Rano Raraku, Rano Kau, and Rano Aroi in the 1980s by geographer John Flenley revealed a record spanning approximately 37,000 years, showing continuous palm-dominated forest cover until the last millennium, when palm pollen was abruptly replaced by grass pollen. Endocarps (seed cases) of the extinct Paschalococos disperta palm have been recovered from archaeological contexts, and the palm's former abundance is attested by its dominance in the pollen record, where it typically comprises 40 to 70 percent of identified pollen grains.^{17, 15}

The initial interpretation of this pollen evidence was straightforward: the Rapanui cut down the forest for agriculture, canoe building, fuel, and the transport of moai, leading to complete deforestation by approximately 1600 CE. This narrative became central to Jared Diamond's influential 2005 book Collapse, which presented Rapa Nui as a parable of environmental self-destruction—an "ecocide" in which a society consumed its own ecological base through reckless overexploitation, triggering famine, warfare, and population collapse before European arrival.¹³

Subsequent paleoecological research has substantially complicated this picture. More recent, higher-resolution sediment cores show that the apparent abruptness of deforestation in the earlier records was partly an artifact of sedimentary gaps spanning several millennia, which compressed what was actually a gradual, spatially heterogeneous process into a single dramatic transition. When continuous, chronologically coherent cores are analyzed, deforestation emerges as having proceeded at different times and rates across different parts of the island, beginning in some areas soon after settlement and continuing in others for centuries.³

The causes of deforestation are now understood as multicausal. Human land clearance for agriculture was certainly a factor, but the Polynesian rat (Rattus exulans), which arrived with the first settlers, played a critical and synergistic role. Rats are voracious consumers of palm seeds and can prevent forest regeneration even without any tree felling. Ecological modeling suggests that a single breeding pair of rats introduced to an island with an estimated 15 million palm trees could produce a population of roughly 11 million individuals within 47 years, destroying approximately 95 percent of palm seeds in the process. Humans cleared patches of forest for planting; rats prevented the forest from regrowing by consuming the seeds of the next generation of trees. This synergy between intentional clearance and invasive seed predation produced island-wide deforestation that neither factor alone would have caused.⁴ Climate variability, including prolonged droughts, further stressed the remaining forest, making deforestation a product of interacting natural and anthropogenic drivers rather than human recklessness alone.³

The collapse debate

Few archaeological narratives have been as widely disseminated or as vigorously contested as the "ecocide" model for Rapa Nui. As popularized by Diamond, the story runs as follows: a growing population, organized into competing clans, consumed the island's forests to transport ever-larger moai in a spiral of competitive statue-building. Deforestation led to soil erosion, crop failure, and the inability to build ocean-going canoes for fishing. Famine ensued, the social order collapsed, and the population crashed from a peak of perhaps 15,000 to 20,000 to just a few thousand before Europeans arrived. The moai were toppled during internecine warfare, and the surviving population was reduced to cannibalism.¹³

Nearly every element of this narrative has been challenged by subsequent research. The revised chronology eliminates the centuries of gradual environmental degradation that the ecocide model requires, compressing the entire sequence into a much shorter timeframe.¹ The deforestation was gradual and multicausal, not a sudden catastrophe driven by log-roller moai transport; the walking hypothesis eliminates the need for massive quantities of timber to move statues.^{8, 3} Morphometric analysis of the island's distinctive stemmed obsidian tools (mata'a), long interpreted as spear points indicating endemic warfare, demonstrates that they were general-purpose cutting and scraping implements used in agriculture and craft production, not weapons.¹²

The population estimates underpinning the collapse model have also been revised downward. Satellite imagery combined with machine learning analysis of agricultural rock gardens across the entire island shows that the total area of lithic mulch cultivation was substantially less than previously claimed. These gardens could have supported a population of approximately 3,000 to 4,000 people, consistent with the estimates made by early European visitors in the 1700s, but far below the 15,000 to 20,000 that Diamond and earlier scholars proposed.⁶

The most direct evidence against a pre-contact population crash comes from ancient DNA. Whole-genome sequencing of 15 ancient Rapanui individuals, radiocarbon-dated from 1670 to 1950 CE, reveals a pattern of stable or gradually growing population from the thirteenth century through to European contact, with no genetic signature of the severe bottleneck that a demographic collapse in the 1600s would have produced. Extensive population genetics simulations reject the collapse scenario, showing instead population continuity until the catastrophic effects of European contact in the eighteenth and nineteenth centuries.⁵

Estimated population trajectory of Rapa Nui^{5, 6, 13}

Rock gardening and agricultural adaptation

In a deforested landscape with thin, nutrient-poor volcanic soils and no permanent streams, the Rapanui developed a distinctive agricultural system based on lithic mulch gardening, also known as rock gardening. This technique involved breaking volcanic rock into fragments and spreading them across planting surfaces, creating a stone veneer that served multiple agronomic functions. The rock mulch reduced evapotranspiration from the soil surface, protected plants and soils from the island's persistent high winds, promoted water infiltration into the root zone, moderated soil temperature fluctuations, and may have enhanced soil nutrient availability through mineral weathering.^{6, 10}

The earliest dated rock gardens on Rapa Nui were constructed in the fourteenth and fifteenth centuries, with the most intensive use evident from the sixteenth through eighteenth centuries. Satellite analysis of the island's rock garden distribution shows that these features are concentrated in areas with favorable combinations of rainfall and soil quality, particularly on the island's windward (eastern and northern) slopes. The leeward interior and the drier western coastal zones show less evidence of intensive cultivation.^{6, 10}

Soil nutrient analysis within and outside of rock gardens reveals that the gardens created measurably different growing conditions. Within the lithic mulch, soils show higher moisture retention and altered nutrient profiles compared to adjacent unmodified surfaces. The primary crops were sweet potato (kumara), taro, yam, and banana—the standard Polynesian crop suite, adapted to local conditions through the innovative application of lithic mulch technology. The overall pattern of land use shows regional variation through time, with some areas being abandoned as rainfall patterns shifted and soil productivity declined, while other areas intensified. This regional dynamism is consistent with a society adapting pragmatically to environmental constraints rather than one locked into a spiral of decline.¹⁰

European contact and demographic catastrophe

The Dutch navigator Jacob Roggeveen became the first European to reach Rapa Nui on Easter Sunday, April 5, 1722, giving the island its European name. Roggeveen's expedition remained only briefly, but the journal entries describe an island with a functioning society: cultivated fields, standing moai, well-organized communities, and a population his crew estimated at several thousand. A violent encounter during the landing resulted in the killing of approximately a dozen islanders by Dutch musket fire, inaugurating a pattern of violence that would intensify with subsequent European visits.¹³

The Spanish expedition of Felipe González in 1770 and the visits of James Cook in 1774 and Jean-François de Galaup, comte de La Pérouse, in 1786 each left accounts of the island's condition. Cook, notably, observed that some moai had already been toppled, though the cause remains uncertain—earthquake damage, intentional acts during inter-clan disputes, or some combination. By Cook's visit, the population appeared smaller than Roggeveen's estimates, though whether this reflected actual decline, seasonal variation, or differences in observer methodology is difficult to determine.

The true demographic catastrophe came in December 1862, when Peruvian slave raiders struck Rapa Nui in a series of violent abductions that eventually captured approximately 1,500 people—roughly half the island's population. The captives were transported to Peru to work in the guano industry under horrific conditions. International pressure eventually compelled the Peruvian government to repatriate the survivors, but the return voyage was devastating. Of approximately 470 Rapanui who boarded the overcrowded repatriation vessel, only 15 survived the journey, the rest having succumbed to smallpox and dysentery. Those 15 survivors carried smallpox back to the island, triggering an epidemic that killed approximately 1,000 more inhabitants. By 1877, the Rapanui population had been reduced to just 111 individuals.¹³

The slave raids were culturally as well as demographically devastating. Among those captured were all the hereditary high chiefs, learned priests, and specialists who held the society's oral traditions, genealogical knowledge, and whatever ability to read the Rongorongo script still existed. The loss of these knowledge-holders severed the transmission of Rapanui cultural memory far more thoroughly than any pre-contact ecological change had done. Chile annexed the island in 1888, subsequently leasing most of its land to a sheep-ranching company that confined the Rapanui to a small area around Hanga Roa. Full Chilean citizenship was not extended to the Rapanui until 1966.

The Rongorongo script

Among the most enigmatic artifacts of Rapanui culture are the Rongorongo inscriptions, a system of glyphs incised into wooden tablets and other objects using obsidian flakes or shark teeth. Approximately two dozen inscribed objects survive, scattered across museums and private collections in Europe and the Americas. The inscriptions comprise roughly 15,000 individual characters drawn from a repertoire of over 400 distinct glyphs, many depicting stylized human, animal, and plant forms. The glyphs are arranged in a boustrophedon pattern—alternating lines read in opposite directions, with every other line inverted—a system unique among the world's writing traditions.¹¹

Rongorongo remains undeciphered, and the fundamental question of whether it constitutes true writing (representing language) or a mnemonic notation system (recording concepts or chants without encoding specific linguistic forms) is unresolved. The small corpus, the absence of bilingual texts, and the extinction of any reading tradition make decipherment exceptionally difficult. No confirmed readings of any Rongorongo text have been achieved, though several scholars have identified plausible structural patterns, including a possible lunar calendar on one tablet.

A critical question is whether Rongorongo was invented independently or inspired by contact with European writing. Roggeveen's 1722 visit and González's 1770 visit, during which the Spanish presented a written treaty for the islanders to sign, have been proposed as possible stimuli for an indigenous script-creation event. However, radiocarbon dating of four Rongorongo tablets preserved in Rome has produced a striking result: while three of the tablets date to the eighteenth or nineteenth century, the wood of the fourth (designated tablet D, or Écheviné) was cut between 1493 and 1509—more than 200 years before any European reached the island. If the glyphs were carved soon after the wood was cut, Rongorongo would predate European contact entirely and represent one of only a handful of independent inventions of writing in human history, alongside Sumerian cuneiform, Chinese script, Mesoamerican writing, and possibly the Indus Valley and Cretan scripts.¹¹

The dating evidence is suggestive but not conclusive. The wood could have been inscribed long after it was harvested, and a single pre-contact date does not establish the antiquity of the script as a system. Nonetheless, the finding has intensified scholarly interest in Rongorongo as a potentially independent writing tradition, and further radiocarbon dating of surviving tablets may help resolve the question.

Ancient DNA and South American contact

Whole-genome sequencing of ancient Rapanui individuals has provided new evidence for two longstanding questions: the island's demographic history and its relationship to South American populations. Analysis of 15 ancient individuals, radiocarbon-dated from 1670 to 1950 CE and sequenced at coverages ranging from 0.4× to 25.6×, confirms that the Rapanui were Polynesian in origin and most closely related to present-day Rapanui descendants. Effective population size reconstructions based on these genomes show steady growth from the thirteenth century into the European contact period, with no evidence of the severe bottleneck that would be expected from a pre-contact demographic collapse.⁵

The same study detected approximately 10 percent Indigenous American ancestry in the ancient Rapanui gene pool, with the statistical distribution of American DNA segments consistent with a contact event occurring between the thirteenth and fifteenth centuries—well before European arrival. This genetic signal confirms earlier findings from modern Rapanui genomes and provides a tighter chronological constraint on when Polynesian and South American populations interacted. Whether Polynesian voyagers reached the South American coast, South Americans reached Rapa Nui, or both events occurred remains an open question, though the Polynesian tradition of long-distance voyaging and the prevailing wind and current patterns of the southeastern Pacific make a Polynesian-initiated contact plausible.⁵

The presence of the sweet potato (Ipomoea batatas), a plant of exclusively South American origin, throughout Polynesia at the time of European contact provides independent botanical evidence for trans-Pacific contact. The Polynesian word for sweet potato, kumara, resembles the Quechua term kumar, suggesting direct borrowing during a contact event. The genetic and botanical evidence together indicate that the Pacific was not a barrier separating Polynesian and American civilizations but a medium through which they occasionally interacted, with Rapa Nui occupying a key position on the route between them.

The modern Rapanui

From the demographic nadir of 111 people in 1877, the Rapanui population has recovered substantially. The island's current population is approximately 7,750, of whom a majority identify as Rapanui. The Rapanui language, a member of the Eastern Polynesian branch of the Austronesian language family, is still spoken on the island, though it faces pressure from Spanish as the dominant language of education, commerce, and government. Cultural revitalization efforts have focused on traditional dance, tattooing, woodcarving, and the annual Tapati Rapa Nui festival, a two-week celebration of Rapanui heritage that draws participants and visitors from across Polynesia and the wider world.

Land rights remain a contentious issue. Much of the island is administered as Rapa Nui National Park, a UNESCO World Heritage Site since 1995, but the Rapanui community has long sought greater control over ancestral lands that were appropriated during the Chilean colonial period. Tensions between conservation mandates, Chilean sovereignty, and indigenous self-determination have shaped the island's modern politics, with periodic protests and occupations of contested sites. In 2017, control of the national park was transferred to the Rapanui-led Ma'u Henua indigenous community, marking a significant step toward local governance of cultural heritage.

The scientific reassessment of Rapa Nui's history carries implications beyond the island itself. The ecocide narrative, which framed the Rapanui as agents of their own destruction, functioned as a morality tale for contemporary environmentalism but also, as critics have noted, shifted responsibility away from the documented historical violence of European colonialism. The emerging picture of a resilient society that adapted to environmental constraints through innovative agriculture, cooperative monument-building, and flexible social organization, only to be devastated by external forces, recenters the colonial encounter as the primary cause of Rapanui demographic and cultural collapse. The island's history, properly understood, is not a cautionary tale about ecological self-destruction but a case study in the vulnerability of small, isolated populations to the diseases, violence, and dispossession that accompanied European expansion across the Pacific.^{5, 6, 13}