In a new study, Rosell et al. look into the earthquake history of the Tambomachay Fault near Cusco in Peru. Cusco has been hit by damaging earthquakes in 1650, 1950, and 1986, and there is also some evidence for another earthquake during Inca times between AD 1418–1471. Very little is known about the causative faults. There is also very limited information on older events. The closest fault to the city is a 20 km-long normal fault at the northern margin of the Cusco Basin, the Tambomachay Fault. Here we constrained the fault’s Holocene slip rate by dating offset lateral moraines, and we identified three Holocene surface ruptures in a paleoseismological trench. The study was recently published open access in τeκτoniκa.
more
A recent study
presented at the GSA meeting concludes that the UNESCO World Heritage site of
Machu Picchu in Peru was intentionally built on faulted bedrock in order to
ease the quarrying of the huge blocks used as construction material (Menegat,
2019). But has Machu Picchu seen big earthquakes in its lifetime? And if so,
can it tell us something about their magnitude? After all, there are plenty of
earthquakes in Peru, not only at the subduction zone but also in the Andes
(e.g., Wimpenny et al., 2018). Some strong instrumental events occurred less
than 100 km away from the Inca site. However, in the area of Machu Picchu we
knew little about strong earthquakes. That’s why in 2016 a group of researchers
from Peru, France, and the UK including myself started to investigate the
active faults around Cusco and archaeoseismological damage to Machu Picchu and
other famous Inca sites nearby in the CUSCO-PATA project.
more
The city of Cusco in Perú has been hit by damaging earthquakes several times in its long history. In Inka times a strong earthquake destroyed parts of the city, and the Spanish invaders documented an earthquake that happened in 1650. Three hundred years later, in 1950, an earthquake destroyed large parts of modern Cusco and in 1986 a M6.1 event also led to damages in the city. In order to better understand the active normal faulting in the region, INGEMMET has launched the project Cusco-PATA (Paleoseismology, Archaeoseismology and Active Tectonics – “pata” also means “scarp” in Quechua). The project brings together scientists from Perú, Spain, France, and the UK. The 2017 field campaign started in mid-April with work on the archaeological sites in and around Cusco and paleoseismological trenching of the Pachatusan Fault. more
Our colleague Carlos Benavente Escóbar from the Instituto Geologico Minero Metalurgico (Peru) brought a book to my attention which was published in 2013: Neotectonics and seismic hazard of the Cusco Region. The book is in Spanish, but you will find it easy to understand what it’s about, because it is full of fascinating images of faults, fault scarps, seismites, liquefaction features, geological maps, and outcrop sketches. Have a look, it’s great! The book can be viewed online for free and is also available for download. more
