Vol.:(0123456789) Natural Hazards (2021) 106:1619–1637 https://doi.org/10.1007/s11069-020-04462-2 1 3 ORIGINAL PAPER Extreme sea levels at Rapa Nui (Easter Island) during intense atmospheric rivers Matías Carvajal 1,2  · Patricio Winckler 3,4,5  · René Garreaud 6  · Felipe Igualt 7  · Manuel Contreras‑López 3  · Pamela Averil 3  · Marco Cisternas 8,2  · Alejandra Gubler 4  · Wolfgang A. Breuer 9 Received: 27 July 2020 / Accepted: 2 December 2020 / Published online: 2 January 2021 © The Author(s), under exclusive licence to Springer Nature B.V. part of Springer Nature 2021 Abstract In addition to the tsunami hazard posed by distant great earthquakes, Rapa Nui (Easter Island), in the Southeast Pacifc Ocean, is exposed to frequent and intense coastal storms. Here, we use sea-level records and feld surveys guided by video and photographic foot- age to show that extreme sea levels at Rapa Nui occur much more frequent than previ- ously thought and thus constitute an unrecognized hazard to the inland’s maritime sup- ply chain. We found that extreme sea-level events, including the two most extreme (March 5th and May 5th, 2020) in our 17-month-long analyzed period (from January 1st, 2019, to May 31st, 2020), resulted from constructive superpositions of seiches on the shelf, storm surges and high tides. By further analyzing time series of atmospheric and wind-generated wave data, we conclude that these extreme sea levels are ultimately driven by the breaking of large waves near the coastline (i.e., wave setup), with lesser contribution of barometric setup and even less of wind setup. We also propose that these large waves were mainly generated from strong, long-lasting, NW winds associated with intense atmospheric riv- ers (long, narrow regions in the atmosphere that transport abundant water vapor) passing over Rapa Nui. Given that the intensity of atmospheric rivers and sea level are thought to increase as climate changes, a deeper understanding of the relation between meteorological and oceanographic processes at Rapa Nui is strongly needed. Keywords Rapa Nui · Easter Island · Seiches · Meteotsunamis · Storm surge · Sea level · Shelf resonance · Atmospheric rivers · Integrated water vapor 1 Motivation Isolated in the southeast Pacifc Ocean, Rapa Nui, also known as Easter Island (Chile; 27,1°S–109,4°W), is the most remote inhabited place in the world (Fig. 1a). Its triangu- lar-shaped surface of ~ 164 km 2 is home to about 7750 people, most of them living in the village of Hanga Roa (Rangel-Buitrago et al. 2018), on the western coast of the island * Matías Carvajal matias.carvajal.ramirez@gmail.com Extended author information available on the last page of the article