The 1877 Iquique earthquake occurred at 21:16 local time on 9 May (0:59 on 10 May

UTC Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communica ...

). It had a magnitude of 8.5 on the

surface-wave magnitude The surface wave magnitude (M_s) scale is one of the magnitude scales used in seismology to describe the size of an earthquake. It is based on measurements of Rayleigh surface waves that travel along the uppermost layers of the Earth. This mag ...

scale. Other estimates of its magnitude have been as high as 8.9 and 9.0 (based on the size of the tsunami). It had a maximum intensity of XI (Extreme) on the

Mercalli intensity scale The Modified Mercalli intensity scale (MM, MMI, or MCS) measures the effects of an earthquake at a given location. This is in contrast with the seismic magnitude usually reported for an earthquake. Magnitude scales measure the inherent force or ...

and triggered a devastating

tsunami A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...

. A total of 2,385 people died, mainly in

Fiji Fiji, officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists of an archipelago of more than 330 islands—of which about ...

from the tsunami.

Historical context

Affected areas in what was then part of Bolivia but is now the Antofagasta region of Chile, had during this period been subject to the Atacama border dispute between the two countries. Under the 1874 boundary treaty between Bolivia and Chile, the border between the two nations as of 1877 followed the 24th parallel south. The terms of that treaty required that Bolivia not levy taxes on Chilean companies mining

nitrate Nitrate is a polyatomic ion with the chemical formula . salt (chemistry), Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are solubility, soluble in wa ...

s between the 23rd and 24th parallels (including the city of

Antofagasta Antofagasta () is a port city in northern Chile, about north of Santiago. It is the capital of Antofagasta Province and Antofagasta Region. According to the 2015 census, the city has a population of 402,669. Once claimed by Bolivia follo ...

) for 25 years, except for agreed duties to be shared between the two countries. Following extensive damage in the 1877 earthquake and tsunami, the municipal authorities in Antofagasta voted for a tax of 10 centavos per

quintal The quintal or centner is a historical unit of mass in many countries that is usually defined as 100 base units, such as pounds or kilograms. It is a traditional unit of weight in France, Portugal, and Spain and their former colonies. It is com ...

(approximately ) of nitrates exported to fund reconstruction of the town. The Chilean Antofagasta Nitrate & Railway Company, a major nitrate mining company in the region, refused to pay, backed by the Chilean government. This dispute resulted in the

War of the Pacific The War of the Pacific (), also known by War of the Pacific#Etymology, multiple other names, was a war between Chile and a Treaty of Defensive Alliance (Bolivia–Peru), Bolivian–Peruvian alliance from 1879 to 1884. Fought over Atacama Desert ...

, fought from 1879 to 1884, by which Chile gained control of territory as far north as

Tacna Tacna, officially known as San Pedro de Tacna, is a city in southern Peru and the regional capital of the Tacna Region. A very commercially active city, it is located only north of the border with Arica y Parinacota Region from Chile, inland f ...

, including Bolivia's entire coastline.

Tectonic setting

Coastal regions of Peru and Chile lie above the

convergent boundary A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a ...

, where the

Nazca plate The Nazca plate or Nasca plate, named after the Nazca region of southern Peru, is an oceanic list of tectonic plates, tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction, along the Peru– ...

is being subducted beneath the

South American plate The South American plate is a major tectonic plate which includes the continent of South America as well as a sizable region of the Atlantic Ocean seabed extending eastward to the African plate, with which it forms the southern part of the Mid ...

along the line of the

Peru–Chile Trench The Peru–Chile Trench, also known as the Atacama Trench, is an oceanic trench in the eastern Pacific Ocean, about off the coast of Peru and Chile. It reaches a maximum depth of below sea level in Richards Deep () and is approximately long; ...

. The rate of convergence across this boundary is measured at about per year. This boundary has been the site of many great

megathrust earthquake Megathrust earthquakes occur at convergent plate boundaries, where one tectonic plate is forced underneath another. The earthquakes are caused by slip along the thrust fault that forms the contact between the two plates. These interplate earthq ...

s, in addition to events caused by faulting within both the subducting and over-riding plates.

Damage

The earthquake shaking caused significant damage over most of the coastal parts of the Tarapacá and

Antofagasta region The Antofagasta Region (, ) is one of Chile's Administrative divisions of Chile, sixteen first-order administrative divisions. Being the second-largest region of Chile in area, it comprises three provinces, Antofagasta Province, Antofagasta, El ...

s. The tsunami flooded St. Mark's Cathedral in Arica. The hulk of the U.S. gunboat ''Wateree'', which had been beached hundreds of metres inland by the final wave of the tsunami triggered by the 1868 Arica earthquake, was moved several kilometres to the north along the coast and nearer the shoreline. In Chile, the tsunami killed a total of 277 people, mainly in the Tarapacá region. The majority of deaths from the tsunamiroughly 2,000were in

, with another five in

Hilo, Hawaii Hilo () is the largest settlement in and the county seat of Hawaii County, Hawaiʻi, United States, which encompasses the Island of Hawaiʻi, and is a census-designated place (CDP). The population was 44,186 according to the 2020 census. I ...

Characteristics

Earthquake

The shaking lasted for five minutes at Caleta Pabellón de Pica, a coastal town south of

Iquique Iquique () is a port List of cities in Chile, city and Communes of Chile, commune in northern Chile, capital of both the Iquique Province and Tarapacá Region. It lies on the Pacific coast, west of the Pampa del Tamarugal, which is part of the At ...

. The area of felt intensity of VIII on the Mercalli intensity scale or greater, extended from about south of Arica to just south of Cobija. This indicates a rupture length of about .

Tsunami

A wave was observed along about of coastline, from

Arica Arica ( ; ) is a commune and a port city with a population of 222,619 in the Arica Province of northern Chile's Arica y Parinacota Region. It is Chile's northernmost city, being located only south of the border with Peru. The city is the ca ...

in the north to

Mejillones Mejillones is a Chilean port city and commune in Antofagasta Province in the Antofagasta Region. Its name is the plural form of the Spanish meaning "mussel", referring to a particularly abundant species and preferred staple food of its indigen ...

in the south. Eight separate large waves were recorded in Arica. The tsunami affected the coasts of Peru and northern Chile and was observed across the

Pacific Rim The Pacific Rim comprises the lands around the rim of the Pacific Ocean. The '' Pacific Basin'' includes the Pacific Rim and the islands in the Pacific Ocean. The Pacific Rim roughly overlaps with the geological Pacific Ring of Fire. List ...

.An oceanic perturbation
Otago Daily Times, Issue 4753, 12 May 1877, Page 2 The tsunami reached a height of in

Samoa Samoa, officially the Independent State of Samoa and known until 1997 as Western Samoa, is an island country in Polynesia, part of Oceania, in the South Pacific Ocean. It consists of two main islands (Savai'i and Upolu), two smaller, inhabited ...

; in Hilo, Hawaii; and in

Sydney Sydney is the capital city of the States and territories of Australia, state of New South Wales and the List of cities in Australia by population, most populous city in Australia. Located on Australia's east coast, the metropolis surrounds Syd ...

, Australia. In Japan, a wave height of was registered in

Kamaishi, Iwate is a city located on the Sanriku rias coast in Iwate Prefecture, Japan. , the city had an estimated population of 32,609, and a population density of 74 persons per km2, in 16,230 households. The total area of the city is Geography Kamaishi i ...

Future earthquake hazard

The rupture area of the 1877 earthquake has been recognised as one of the major

seismic gap A seismic gap is a segment of an active fault known to produce significant earthquakes that has not slipped in an unusually long time, compared with other segments along the same structure. There is a hypothesis or theory that states that over long ...

s on the plate boundary, known as the "Northern Chile Seismic Gap". The = 7.7 2007 Tocopilla earthquake occurred at the southern edge of the gap, but is not considered to have necessarily reduced the risk of a great megathrust earthquake within this area. In 2005, a recurrence period of 135 years was estimated for great earthquakes along this part of the plate boundary, suggesting that a similar earthquake to the 1877 event was likely in the early 21st century. The

2014 Iquique earthquake The 2014 Iquique earthquake struck off the coast of Chile on 1 April, with a moment magnitude of 8.1–8.2, at 20:46 Time in Chile, local time (23:46 Coordinated Universal Time, UTC). The epicenter of the earthquake was approximately northwest ...

struck in the same seismic gap with a magnitude of = 8.2.