Magnitude 5.8 Earthquake in the Afar Region of Ethiopia linked to activity on Mount Dafan.

The Ethiopian Geological Institute has reported a Magnitude 5.8 Earthquake at a depth of 10.0 km, in the Awash Fentale Woreda (District) of the Afar Region of Ethiopia, about 150 km to the northeast of Addis Ababa, slightly after 4.50 am local time (slightly after 0.50 am GMT) on Saturday 4 January 2025. There are no reports of any damage or injuries arising from this quake, but it was felt as far away as Addis Ababa, and it is possible that some minor damage has occurred.

The approximate location of the 4 January 2024 Ethiopian Earthquake. USGS.

This is the latest in a series of Earthquakes in the Central Ethiopia, which began in the third week of December 2024. Clusters of Earthquakes are concerning in northern or central Ethiopia, as the area is volcanic, and seismic movements can be linked to magma moving into chambers beneath volcanoes from deeper in the Earth, which in turn can be a predictor of future volcanic eruptions. On this occasion the Ethiopian Geological Institute has suggested that the Earthquakes may be linked to a fissure eruption on Mount Dafan, a shield volcanoe in the Dulacha Woreda, which opened on 2 January producing a sustained jet of steam and hot water. Residents of the area have been evacuated as a precaution against a future, larger eruption.

A vent which opened on Mount Dafan in the Dulacha Woreda of Ethiopia on 3 January 2024, producing a sustained jet of steam and hot water. Ethiopian Geological Institute/Facebook.

The deserts of Northern Ethiopia and Southern Eritrea are extremely volcanically active, with dozens of volcanoes fed by an emerging divergent margin along the East African Rift. The African Plate is slowly splitting apart along the Ethiopian Rift and the East African Rift to the south (which is splitting the Nubian Plate to the West from the Somali Plate to the East). Arabia was a part of Africa till about thirty million years ago, when it was split away by the opening of the Red Sea Rift (part of the same rift system), and in time the Ethiopian and East African Rifts are likely to split Africa into a number of new landmasses. This rifting exerts pressure on the rocks around the margin of the sea, slowly pushing them apart, not smoothly but in fits and starts as the pressure overcomes the tendency of the rocks to stick together, creating shocks that we experience as Earthquakes.

Rifting in East Africa. The Danakil Microplate is the red triangle to the east of the Afar depression at the southern end of the Red Sea. Università degli Studi di Firenze.

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Eruption on Mauna Loa Volcano, Hawai'i.

Mauna Loa Volcano, located on Big Island Hawai'i, and considered to be the world's largest active volcano, began erupting at about 11.30 pm local time on Sunday 27 November 2022 (about 9.30 am on Monday 28 November GMT), producing effusive lava eruptions from the Moku‘āweoweo Caldera. By the following morning, the eruptive activity had migrated to the upper Northeast Rift Zone, producing lava streams descending the volcano's northern flank. An initial ash advisory was issued but quickly withdrawn, and no properties are currently threatened by the lava flows, which are all contained within the Hawai‘i Volcanoes National Park.

Lava flows moving northeast downslope of Mauna Loa volcano from the Northeast Rift Zone eruption, observed from Saddle Road at 6.00 am Hawai'i time on 29 November 2022. United States Geological Survey.

Mauna Loa is a shield volcano (broad, dome-shaped volcano) made up largely of successive layers of basalt lava, which have been flowing from fissures on roughly the same spot for about 700 000 years. The volcano has risen from a seafloor 5000 m beneath the surface to its current altitude of 4170 m above sealevel, making it the world's tallest mountain of any sort (Everest reaches higher, at 8848 m above sealevel, but rises from the Tibetan Plateau, more than 5000 m above sealevel, so it's height is much lower). The volcano covers an area of about 5271 km², and makes up about half the area of Big Island.

Aerial photograph of the dominant fissure 3 erupting on the Northeast Rift Zone of Mauna Loa, taken at approximately 8.00 am Hawai'ian Standard Time on Tuesday 29 November 2022. Fountains were up to 25 m high, and the vent was feeding the main lava flow to the northeast. United States Geological Survey.

Despite being a highly active volcano (with 33 eruptions since 1843), Mauna Loa is not considered to be a particularly dangerous volcano, and injuries associated with its eruptions are rare. This is because most of the activity on the volcano is in the form of slow moving lava flows, which most people are capable of simply walking away from. The last eruption on Mauna Loa occurred in 1984, when lava flows reached within 8 km of the town of Hilo, the largest settlement on Big Island, causing no damage or injuries. However, since the 1980s the population of Big Island has more than doubled, increasing the risk of lava flows reaching populated areas.

Aerial photo captured during an overflight of the Northeast Rift Zone eruption of Mauna Loa between 5.00 and 6.30 pm Hawai'ian Standard Time on 28 November 2022. This photo shows fissure vents erupting above 3 km above sealevel on the Northeast Rift Zone of Mauna Loa. Civil Defence Patrol/United States Geological Survey.

The islands of Hawai'i have formed as a result of hotspot volcanism, with a mantle plume hotspot currently located under Big Island, Hawai'i, and each of the other islands being the result of previous activity from the same hotspot, with the oldest Islands in the northwest and newest in the southeast. A volcanic hotspot is an area where magma from deep inside the Earth is welling up through the overlying plate (in this case the Pacific) to create volcanism at the surface. Volcanoes move as they erupt, swelling as magma enters their chambers from bellow, then shrinking as that magma is vented as lava.

The position of the Hawai'i Hotspot relative to the islands of Hawai'i. Joel Robinson/USGS/Wikimedia Commons.

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Eruption on Mount Fagradalsfjall, Iceland.

The Icelandic Meteorological Office has reported an eruption on Mount Fagradalsfjall, part of the Krýsuvík-Trölladyngja Volcanic System, on the Reykjanes Peninsula. The eruption started at about 8.45 pm local time on Friday 19 March 2021, with a fissure 500-700 m in length opening up to the southeast of the main volcano, and produced lava fountains up to about 100 m high, with the lava spreading to cover an area of about 1 km² by the next day. The eruption persisted for several days, but decreased in intensity steadily. While spectacular, the eruption was not particularly dangerous, attracting large crowds of onlookers, some of whom took the opportunity to cook sausages on the cooling lava.

 

Crowds of onlookers watch a fissure eruption to the southeast of Mount Fagradalsfjall on the Reykjanes Peninsula, Iceland. AFP/Getty Images.

The Krýsuvík-Trölladyngja Volcanic System comprises a composite fissure swarm about 50 km in length, with no central volcano, but several small shields (i.e. volcanic structures made up largely of overlapping lava deposits that resemble upturned bowls rather than a cone) including Mount Fagradalsfjall. The system has been essentially quiet for about 800 years, with the last known eruption happening in the fourteenth century, and the last major eruption two centuries before that. However, an eruption in the area was expected, as a very large number (over 50 000) of earthquakes had been recorded beneath the system over the past few weeks, something which is often indicative of fresh magma moving into chambers beneath inactive volcanoes.

 

Earthquakes with a Magnitude of 4.0 or greater on the Reykjanes Peninsula over the past 30 days. USGS.

Iceland lies directly upon the Mid-Atlantic Ridge, a chain of (mostly) submerged volcanoes running the length of the Atlantic Ocean along which the ocean is splitting apart, with new material forming at the fringes of the North American and European Plates beneath the sea (or, in Iceland, above it). The Atlantic is spreading at an average rate of 25 mm per year, with new seafloor being produced along the rift volcanically, i.e. by basaltic magma erupting from below. The ridge itself takes the form of a chain of volcanic mountains running the length of the ocean, fed by the upwelling of magma beneath the diverging plates. In places this produces volcanic activity above the waves, in the Azores, on Iceland and on Jan Mayen Island. All of this results in considerable Earth-movement beneath Iceland, where Earthquakes are a frequent event.

 

The passage of the Mid-Atlantic Ridge beneath Iceland. NOAA National Geophysical Data Center.

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Magnitude 4.8 Earthquake in the Central Highlands of Madagascar.

The United States Geological Survey recorded a Magnitude 4.8 Earthquake at a depth of 16.1 km, roughly 29 km to the southeast of the town of Fandriana in Amoron'i Mania Region, in the Central Highlands of Madagascar, slightly after 10.00 9m local time (slightly after 7.00 pm GMT) on Wednesday 13 May 2020. There are no reports of any damage or casualties associated with this event, but it was felt in Antanarivo and Ambamo.

The approximate location of the 13 May 2020 Madagascar Earthquake. USGS.

Madagascar is a former chunk of the ancient continent of Gondwana, that was formerly wedged between Africa, Antarctica, India and the Seychelles. It split away from Africa from about 182 million years onwards and from the other continents between about 115 and 120 million years ago. It currently sits in the western Indian Ocean forming part of the Somali Plate (the eastern chunk of the African Plate, which is currently splitting in two along the East African Rift). However this Indian Ocean segment can be seen as a number of smaller tectonic blocks, such as the Seychelles Microplate and Madagascan Plate, which are being squeezed together by the active rifting on the East African Rift and Indian Ocean Ridge.

 

The position of Madagascar on the Somali Plate. Wikimedia Commons.

 

Madagascar itself has two main centres of seismic activity, the Alaotra-Ankay Rift Valley, which is slowly splitting the Central Plateau of Madagascar in half, and which is considered by some to be an extension of the East African Rift, and the Ankaratra Plateau, which is a shield volcanic structure located on this rift, which has reached about 2700 m above sea level in a series of prehistoric lava flows. This volcano has not undergone any eruptive activity in recorded history, but does undergo periodic bouts of seismic activity (Earthquakes).

 

A hill bisected by rifting in the Central Highlands of Madagascar. Bukla Tours.

 

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here. 

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Eruptions from new fissure on Mount Ambrym, Vanuatu.

The Vanuatu Geohazards Observatory has reported an eruption from a new fissure on Mount Ambrym, a basaltic island volcano in the New Hebrides Island Arc. The activity began with a series of small earthquakes, leading up to the onset of eruptive activity at about 6.00 am local time on Saturday 15 December 2018, from a fissure to the southeast of the Lewolembwi  Crater, which produced lava fountains about 40 m high and a lava flow which ran to the east and filled much of the Lewlembwi Crater. Activity on the volcano persisted for another two days, with the lava fountains slowly being replaced with ash emissions.

Lava fountaining from a new fissure on Mount Ambrym, Vanuatu, on 15 December 2018. John Tasso/Vanuatu Island Experience.

Mount Ambrym comprises a complex of basaltic structures overlying an older shield volcano, which was initially formed in a massive eruption in about 50 AD, since when it has continued to grow. It has a 12 km widr caldera, which contains two smaller cones (Marum and Benbow) as well as seven smaller craters, Lewolembwi, Marumliglar, Mbwelesu, Minnei, Niri Mbwelesu, Niri Mbwelesu Taten, and Niri Mbwelesu Taten, and four cinder cones, Dalahum, Tuvio, Vetlam, and  Woosantapaliplip.

Vanuatu is located on the southwestern fringe of the Pacific Plate, close to its boundary with the Australian Plate, which is being subducted along the New Hebrides Trench, to the west of the islands. The subducting Australian Plate passes under the islands of Vanuatu as it sinks into the Earth, causing Earthquakes as the plates stick together then break apart as the pressure builds up. As the plate sinks further it is partially melted by the heat of the Earth's interior. Some of the melted material then rises through the overlying Pacific Plate, fuelling the volcanoes of Vanuatu.

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Tourists injured after lava bomb strikes boat by coast of Hawai'i.

Twenty three people have been injured, three of them seriously, after a lava bomb (chunk of lava thrown from a volcano, in either liquid or solid form) from Mount Kilauea struck a tour boat of the coast of Hawai'i on Monday 16 July 2018. The volcano began erupting from a new fissure on its eastern flank on 3 May 2018, since when a series of fissures have opened up, producing several major lava flows, which have destroyed many homes and other properties, and at least one of which has reached the sea, producing a laze (toxic haze resulting from hot lava hitting water, producing chemical-laden steam, which had led to the U.S. Coast Guard imposing a 50 m exclusion zone around areas of the coast that were being reached by the lava, though the boat struck by the lava bomb despite being outside this zone.

Damage to a tourist boat struckby a lava bomb off the coast of Hawai'i on 16 July 2018. Hawai'i Department of Land and Natural Resources.

The islands of Hawai'i have formed as a result of hotspot volcanism, with a mantle plume hotspot currently located under Big Island, Hawai'i, and each of the other islands being the result of previous activity from the same hotspot, with the oldest Islands in the northwest and newest in the southeast. A volcanic hotspot is an area where magma from deep inside the Earth is welling up through the overlying plate (in this case the Pacific) to create volcanism at the surface. Volcanoes move as they erupt, swelling as magma enters their chambers from bellow, then shrinking as that magma is vented as lava.

 The position of the Hawai'i Hotspot relative to the islands of Hawai'i. Joel Robinson/USGS/Wikimedia Commons.

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