The traveltime residua were inverted for 1-D depth-dependent velocities with the inversion performed in iterations. The final bandpass filter of 840s represents the optimum waveform smoothing needed for the effective cross-correlation in the waveform processing while preserving maximum information (Fig. However, compared to our results, the global tomographic models are well resolved for larger spatial scales and smeared by the presence of the slab. The problem is that the magma chamber can be tens of kilometres deep, and there's no way of knowing how much moremagma is still in the chamber. The droplets of sulphuric acid emitted to the atmosphere during eruption can temporarily alter the climate, sometimes for years. The inverted representative depth-dependent velocities and the Vp/Vs ratios calculated from traveltime residua (Fig. Here, a major break in the crust known as the Vitiaz Fracture Zone has developed, and the Tonga Trench makes a sharp turn to the west. 6). 2009 eruption[3] arose from two vents located to the south and northwest of Hunga Haapai. The Samoa hotspot lies~130km from the northern termination of the Tonga Trench, at a place where the Pacific plate pulls apart and its southern portion subducts beneath the Australian plate, while its northern portion continues westwards. In: Richards MR, Gordon R, Van der Hilst RD (eds) American Geophysical Union, pp 277288, Kellogg LH, Wasserburg GJ (1990) The role of plumes in mantle helium fluxes. suffer earthquakes). [7] Its northern and southern portions were filled by volcanic deposits from previous eruptions. First, pronounced negative velocity anomalies in the mantle wedge and the Lau back-arc region at depths less than250km (Figs. We confront these images with geochemical findings on ocean island basalts, the distribution of seismicity, the deformation and extension in the area, and provide the depth extent of the SamoaTonga contact. [66], Two people were killed in Peru and two fishermen were injured in San Gregorio, California. In particular, they differ for the southern and northern parts of the Tonga subduction region. https://doi.org/10.1016/j.epsl.2018.09.005, Wiens DA, Shore PJ, McGuire JJ, Roth E, Bevis MG, Draunidalo K (1995) The southwest pacific seismic experiment. On the other hand, debates on the Samoan volcanic lineament as a plume-driven or non-plume-driven hotspot chain involves limitations due to predicted age of some volcanoes (Natland, 1980). [15][19], After the 2015 eruption, the smaller Hunga Tonga island, approximately 1.5km (0.93mi) to the northeast of Hunga Haapai, became attached to the crater via a 380m (1,250ft)-wide tombolo, and further sandy deposits had built up at the southern end of the crater's connection with Hunga Haapai. Seismic low-velocity structure in the mantle imaged in global tomography models could represent a plume originating at the core-mantle boundary (Gurnis et al., 2000; Courtillot et al., 2003; Montelli et al., 2004; French and Romanowicz, 2015; Chang et al., 2016; Maguire et al., 2018). "If this happened like threehours later in the middle of the night [when]people are asleep, it could have been a lot worse.". The volcano was featured in a segment of the television program Angry Planet in 2009.[32]. They also displayed rather positive values at depths of 150250km. 6. a, b The observed Vp/Vs values. Note that the plots do not show the entire set of the analysed waveforms. Therefore, the traveltime residua were retrieved from the cross-correlation of waveforms further refined by correlating with the common wavelet obtained by the principal component analysis. The obtained results are consistent with other findings. 9a). Similar to the Niuafo'ou plate, the northern and southern boundaries are less well constrained. [33] The eruption continued into 2015, with a tall ash cloud rising 3km (9,800ft) into the sky on 6January 2015. Here, rocks go through a pressure-induced isochemical phase transition from olivine to its high-pressure polymorphs (to wadsleyite at 410km and then to ringwoodite at 520km) (Ringwood, 1975). Note that the imaged surface does not represent the actual slab geometry. This back-arc tension causes the arc crust to split. J Geophys Res Solid Earth 118:59205938. Second, pronounced negative P- and S-wave anomalies accompanied by changes in the Vp/Vs ratio reaching depth of~500km are detected around 22S latitude and coincide with the gap in the seismicity (Fig. https://doi.org/10.1785/0220170027. Volcano researchers call this a fuel-coolant interaction: it produces volcanic particles and blasts moving at supersonic speeds.). (1997), while the Vs velocity variations exhibited a fast slab (0.20.4km/s) and a slow back arc and spreading centre (0.30.5km/s) in respect to the best fitting model. An underwater volcano off Tonga erupted on Jan. 15, triggering tsunami warnings and evacuation orders in Japan and causing large waves in several South Pacific islands, where footage on social media showed waves crashing into coastal homes. The cross-correlation of waveforms for calculating accurate differential traveltimes became popular after developing the double-difference location algorithm by Waldhauser and Ellsworth (2000) and the double-difference tomography method by Zhang and Thurber (2006). In addition, numerous geochemical studies are in favour of the plume model (Hart et al. (1997) did not include the S-waves in their interpretation and, therefore, no Vp/Vs constraints on a possible distribution of melt and volatiles were provided. 1b), they can be perceived as a whole upper-mantle contrasting feature. To visualize this, imagine cutting an orange (the Earth) with a knife (the slab); a deep cut makes a straight line on the surface of the orange and an angled cut makes a curve. [31], The volcanic eruption drew worldwide attention. In the case of Hunga Tonga-Hunga Ha'apai, researchers had previously looked at the chemical composition of the volcano'slava sediment from aneruption in 2009. 57) were detected along the termination of the earthquakes in the northern Lau Basin (Fig. [71], On 15 January a satellite radar survey showed that most of the island had been destroyed, and only small parts remained. In its first statement the countrys government confirmed three casualties, including a British national who died while saving her dogs. [36] Large rocks and wet, dense ash were being ejected up to 400m (1,300ft) into the air. The deepest earthquakes occur within the core of subducting slabs - oceanic plates that descend into the Earth's mantle from convergent plate boundaries, where a dense oceanic plate collides with a less dense continental plate and the former sinks beneath the latter. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. https://doi.org/10.1002/2017JB014730, Martin K (2014) Concave slab out board of the Tonga subduction zone caused by opposite toroidal flows under the North Fiji Basin. These processes were indicated also by Chang et al. They were responsible, for example, for the 1960 Chile and 2011 Tohoku (associated with the infamous Fukushima incident) events. Moreover, focusing on earthquakes reported in the Global CMT catalog (Dziewonski, et al., 1981; Ekstrm, et al., 2012) offers an ideal source of accurately known locations and origin times. 11a,b are not the artefacts of data processing but they really reflect remarkably different properties of the upper mantle westwards and eastwards of the slab. Blue represents ocean depths of a kilometer or so and brown shades are shallower. The authors declare the following financial interests/personal relationships which may be considered as potential competing interests. Price et al. 3). ; and Gill, J.B. "Mineralogy and Geochemistry of the Younger Volcanic Islands of Tonga, S.W. Depth is colour-coded; azimuth/elevation of the view angle is 295/12. "A Petrological Study of the Younger Tongan Andesites and Dacites, and the Olivine Tholeiites of Niua Fo'ou Island, S. W. Note a higher Vp/Vs ratio down to 600km depth in the northern segment (magenta line in (d)). Institute of Geophysics, Czech Academy of Sciences, Bon II/1401, 141 31, Prague, Czech Republic, You can also search for this author in Pacific. [43], In June2015, entrepreneur Ian Argus Stuart became the first person to overnight on this new island formation. He also said the fact it happened in daylight was a small positive. [2], Nuku'alofa and Neiafu have hospitals equipped with limited emergency and outpatient facilities. The large caldera is submerged and measures 5 km in diameter. In that case, it sits at the Centre of two major tectonic plates, the Indo Australian plate in the west and the pacific plate in the east . In this way, we suppressed the differences between individual traces produced mainly by scattered waves following the direct waves. Strong negative velocity anomalies were confined to depths of 150250km; positive anomalies were mostly located at depths of 500670km. briefly describe how the ocean depth changes as you approach and cross the tonga plate boundary from east to west. The waveform processing at the MSVF station resulted in 308 and 358 wavelets for the P- and S-waves, respectively (Fig. Mantle plumes, first suggested by Wilson (1963) and Morgan (1971), represent relatively hot, low-density mantle material that ascends because of its buoyancy. This is consistent with the observed low-velocity perturbations shown in Fig. (2000), Richards et al. PubMedGoogle Scholar. The volcano's ventwas above water before disappearingbelow sea leveljust afew days (or hours) prior to Saturday's catastrophic eruption, according to Dr Handley. The errors of manual picking are due to noise in data up to2s (see Fig. In addition, modelling studies show that the slab stagnation is often accompanied by the retreat of trench (van der Hilst and Seno, 1993) which also promotes slab flattening in the transition zone (Griffiths et al., 1995; kov et al., 2002; kov and Bina, 2013). Phys Earth Planet Inter 74(12):7588. This is one of the fundaments that discriminate convective flows of plate tectonic movements primarily driven by sinking of cold plates in favour of deep-seated plumes driven by heat exchange (Morgan, 1971; Foulger and Natland, 2003; Foulger, 2010). This network consists of 152 broadband stations, globally distributed and providing open access data (https://www.iris.edu/hq/programs/gsn). Spending 11nights on the island, Stuart survived eating nothing but seagull eggs and squid. Hrubcov, P., Vavryuk, V. Contact of the Samoan Plume with the Tonga Subduction from Intermediate and Deep-Focus Earthquakes. [14], Samples from the islands suggest a long eruptive history. Such scatter is visible in Fig. An, One of the main air pollutants commonly associated with using gas stoves is nitrogen dioxide which is a byproduct o, The PLI scheme, which is Indias policy instrument to improve manufacturing vis--vis solar power and batteries, is, Many of West Bengals natural resources have been degraded by illegal rackets run by people who allegedly have the, Both are set in the Dibang river valley in Arunachal Pradesh, which is home to the indigenous Idu Mishmi and Adi co, Understanding the Geology of the Tonga Volcano. This bay has later become separated from the open ocean by a shallow sandbar, forming a lagoon. . The differential traveltimes are usually calculated by the cross-correlation of waveforms with a reference noise-free waveform of a typical shape, for which the arrival time is well determined and which yields high correlations with other waveforms. The Tonga wedge and the associated back-arc Lau Basin are imaged by low-velocity anomalies (Zhao et al., 1997; Koper et al., 1999; Conder and Wiens, 2006) in agreement with the results from attenuation studies detecting an extensive zone of high attenuation in the uppermost mantle (Roth et al., 1999; Wei and Wiens, 2018). News from Tonga is sparse because communications are severely hampered. This subduction turns into a transform fault boundary north of Tonga. a, b The whole Tonga back-arc region; (c,d) the northern Tonga segment delimited by the latitude 20S. [61] The eruption set off a massive atmospheric shock-wave travelling at about 300m (980ft) per second. The eruption caused a 1.2-metre (four-foot) tsunami wave, Australias Bureau of Meteorology said. Whenmagma hitswater, it causes an explosive interaction between the two as the water rapidly flashes to steam, Professor Bryan said. The colour-coded velocity perturbations v/v in the upper mantle around the Tonga slab bordered by the transform fault between Tonga-Kermadec at latitude of 26S. https://doi.org/10.1111/j.1365-246X.2004.02450.x, kov H, Bina CR (2013) Effects of mantle and subduction-interface rheologies on slab stagnation and trench rollback. As an extension of this zone of tectonic turbulence, there is an active subduction trench along the Tonga archipelago, where the Pacific plate is pushed beneath the Indo-Australian Plate. The perturbations v are normalized to the average velocity v along the whole ray paths and projected onto the foci. Earth Planet Sci Lett 120:395407. 1. Science 278:254257. https://doi.org/10.1785/0120040221, Schellart WP, Spakman W (2012) Mantle constraints on the plate tectonic evolution of the TongaKermadecHikurangi subduction zone and the South Fiji Basin region. However, the comparison of variations of the Vp/Vs ratios at stations MSVF and RAR is not so straightforward, because both stations have different epicentral distance and the Vp/Vs ratio for longer rays (station RAR) might be more smoothed than for shorter rays (station MSVF) due to averaging along the ray path. TheFiji Plateau is a high-altitude, hot zone on the young oceanic crust of the Pacific Ocean. Thermal modelling suggested a counter-flow originating in the subduction mantle wedge and its upwelling in the back-arc (Koper et al., 1999). 1). Do you recognise the landforms? Geochem Geophys Geosyst 9(5):Q05018. The date the eruption began is uncertain. The time residuals of the P-waves ranged mostly from 3 to 3s; the residuals of the S-waves ranged mostly between 7 and 3s. Similarly, processing at the RAR station resulted in 325 and 404 wavelets for the P- and S-waves, respectively. Subduction zones form where a plate with thinner (less-buoyant) oceanic crust descends beneath a plate with thicker (more-buoyant) continental crust. https://doi.org/10.1029/2004JB003433, Trugman DT, Shearer PM (2017) GrowClust: a hierarchical clustering algorithm for relative earthquake relocation, with application to the Spanish Springs and Sheldon, Nevada, earthquake sequences. The low-temperature and high-velocity patterns indicate a stagnant slab (Chen and Brudzinsky, 2001). This required extracting accurate traveltime residua between observed and calculated direct P- and S-wave arrivals for individual events at a given station. https://doi.org/10.1016/j.epsl.2013.08.011, kov H, van Hunen J, van den Berg AP, Vlaar NJ (2002) The influence of rheological weakening and yield stress on the interaction of slabs with the 670km discontinuity. We selected the time window around the theoretical traveltimes and independently extracted the direct P- and S-waves. https://doi.org/10.1016/j.epsl.2006.03.049, Montelli R, Fukao G, Dahlen FA, Hung S-H (2004) Finite-frequency tomography reveals a variety of plumes in the mantle. "The satelliteimages, if you compare from the 6th of Januaryto twohours before the eruption, somewhere in that time frame themiddle cone had gone," she said. The highest geochemical enrichment values (Price et al., 2014, their Figs. An active rift or spreading center separates the Tonga Plate from the Australian Plate and the Niuafoou microplate to the west. Records from the Global Volcanism Program show that the last period of activity at Hunga Tonga-Hunga Ha'apai, which began in December 2014, lasted just over a year. They were introduced to explain the intraplate oceanic island chains ageing progressively along the chain in the direction of plate motions. https://doi.org/10.1130/G31937.1, Ringwood AE (1975) Composition and petrology of the earths mantle. The inset shows the position of the Tonga-Fiji-Kermadec subduction zone (red box). 12b) are artificially amplified by a factor of 2.5 to eliminate a potential smoothing effect produced by roughly twice larger epicentral distance at RAR than at MSVF. Such islands dont last long thanks to sea erosion and future volcanism but they are a boon for scientists studying young landforms and their effects on life-sustaining processes. [7] Before the 2015 eruption, the two subaerial islands were about 1.6km (0.99mi) apart,[12] and were each about 2km (1.2mi) long. Dr Nebel said he suspected there would likely be more eruptions in the near future. Positive velocity anomalies of~3%for the P- and~1% for the S-waves in the mantle transition zone at depths of 410670km point to the retention of high amount of the subducted material. A seafloor survey revealed a large, shallow underwater depression or a caldera to the south of the volcano, about 4 km by 2 km. a, b The velocity perturbations of the P- and S-waves west of the Tonga slab (station MSVF); c, d velocity perturbations of the P- and S-waves east of the Tonga slab (station RAR). Earth Planet Sci Lett 379:95103. These are the sites where tectonic plates grind against each other, creating a continuous belt of volcanoes and earthquakes all along. In addition, the smooth and rather small RAR anomalies compared to large systematic MSVF variations prove that the uncertainties due to location errors are insignificant and the methodology based on the waveform cross-correlation is highly accurate for both P- and S-waves. https://doi.org/10.1016/0031-9201(92)90069-8, Giardini D, Woodhouse JH (1984) Deep seismicity and modes of deformation in Tonga subduction zone. Above the surface of the water, a volcanic island built by previous eruptions is the only visible sign of the volcano. J Volcanol Geotherm Res 156(34):315331. since the pacific plate is denser, it slides beneath the . Conder and Wiens (2006) expanded the P- and S-wave data from regional studies by data from the 20012002 SAFT experiment (Tibi and Wiens, 2005) and jointly inverted for the Vp and Vp/Vs structure. Due to the proximity to the subducting plate, the TongaSamoa region (Fig. https://doi.org/10.1007/s00024-005-0021-y, Zhao D, Xu Y, Wiens DA, Dorman L, Hildebrand J, Webb S (1997) Depth extent of the Lau Back-Arc spreading center and its relation to subduction processes. Chains ageing progressively along the whole Tonga back-arc region at depths of.. There would likely be more eruptions in the subduction mantle wedge and Vp/Vs... Crust descends beneath a plate with thinner ( less-buoyant ) oceanic crust descends beneath a plate with thicker more-buoyant... The two as the water, a volcanic island built by previous eruptions data ( https: //doi.org/10.1130/G31937.1 Ringwood... Arose from two vents located to the west ( 34 ):315331. since the Pacific plate is,. Subduction-Interface rheologies on slab stagnation and trench rollback volcanic eruption drew worldwide attention 61... 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