Happy to meet again with the steemians, hopefully still in good health and no shortage of any kind. I still want to continue the discussion about the history of volcanoes in the world and its terrible eruption, I really like everything about the mountain let alone a very mysterious and exotic volcano, okay I want to directly discuss it and hopefully useful!
The eruption of Medina
Prince Mohammed bin Abdulaziz's international airport is the main gate of the holy city of Madinah al-Munawwarah. It is also one of the two main entrances to the two holy cities for Muslims besides King Abdul Aziz's international airport in Jeddah. The airport is located on the northern outskirts of the holy city of Madinah, not far from historic Uhud Mountain. If we look at the eye from here, Uhud's barren mountain with a reddish-brownish-brown ornament looks indulgent in the southwest.
The landscape is also found in the west, north, and east. But not to the south. As far as the eye could see only the black hills were visible, with its constituent rocks much rougher than the rocks of Mount Uhud. Very little information is available about these black hills. But who would have thought, behind the lack of information, these black hills are truly invisible traces of one of the tensest periods throughout the history of the holy city of Madina. This is the basaltic lava sediment of the Madinah Eruption, a huge eruption that almost broke Madina.
A calendar shows Monday 1 Jumadil Akhir 654 Hijriyyah when a vibration began to shake the holy city of Medina. The merchants, pilgrims of the holy land, the inhabitants and all the other human beings who are living or living in the holy city feel it. Everyone hoped that the vibration was just an ordinary earth tremor that would stop immediately as soon as it came. But that hope vanished like a vapor disappearing into the air. Imagine, in the next four days a succession of vibrations for the sake of vibration of the land just keep going over and over again. The intensity is increasingly tight and often. On Friday morning, at least 18 loud vibrations rocked in just a short time. And in the afternoons, when people were gathering at the Nabawi Mosque waiting for Friday prayers, a loud thrill, hardest among all the previous tremors, startled everything. Undoubtedly all of these invite questions in everyone's heart. Anxiety began to arise. Moreover, the vibration after vibration continues after Friday prayers, though not as hard as before.
The drama reached its climax on Saturday morning after dawn prayer, coinciding with July 1, 1256. Suddenly the quiet and stillness of the morning were interrupted by a thunderous ensuing sound that came from the direction of al-Hijaz in the southeast. With him came a fountain of bluish red blaze into the sky in large numbers. There are so many fireballs that look like fireworks so that their lights shine on the horizon like the sun. For days and days, the fountain of fire continued unabated and even more and more. Now the nights in the holy city of Madinah changed dramatically to as bright as daylight. So bright that night so that the parts of Raudhah and the tomb of the Prophet in the compound of the Mosque of Nabawi like highlighted sunlight constantly. The bright light can even be seen clearly from Tayma 'and the holy city of Makkah al-Mukarramah, whereas both are within 300 kilometers of the source of these fireballs.
The historian al-Qastlaan writes, the brave people of the Bedouin who tried to approach the point of the source of the fire burst into amazement at the sighting scene. A thick, viscous fluid that is very dilute red-bluish with some parts blackened looks bubbling. In the background were six spray-filled fountains of burning fireballs spilling out into the sky. All the fluid moves to flow gently like a river while dragging rocks, trees, soil and whatever it takes. A thundering sound like a continuous lightning continued. Sulfur-scented pungent smoke continues to billow, saddening the eyes and smothering the chest. So thick as the smoke that the air is like a constant mist. As a result, the Sun was only seen as a reddish roundabout. The air near this strange viscous fluid was so hot that no one dared to approach him any closer than two darts (+/- 200 m).
In the present, we know what the people of Medina were facing when it was a hot lava of volcanic eruption products. With the latest technology, it is relatively easy to know what is going on by flying the radas (instrument) in a high enough position above the hot lava, both inside non-crew aircraft and via remote sensing satellites. Like the eruption of Holuhraun, the Madinah eruption is sourced from a crack in the segment of the earth crust about a kilometer southeast of the holy city of Medina. I do not know how long the crack, but from it basaltic magma flooded out while spurting up to tens of meters into the air. A number of hilly pitted bumps are formed along this crack, called the cone skin (cinder cone). The watery magma then flows as a lava along the contours of the local earth toward the lower places. At the peak of this hot lava was collected in such a way as a kind of lava lake 3 meters deep that stretches along the 23 kilometers.
The eruption of Medina is a manifestation of the existence of a volcano in the Arabian peninsula. Yes. Although the majority of its parts are desert climates, the largest landscape of the peninsula on earth does not merely contain a sea of barren sand. Such deserts are found only on the southern and southeastern sides as deserts Ar-Rub 'al-Khali, which is the largest loose sand sea in the earth.
The peninsula is also not just the land where the celestial religions were born, the land where the prophets and apostles were sent and the land where the two Muslim holy cities were founded. But more than that, this peninsula is also one of the geological wonders that hard to find equivalent elsewhere. Some of the Arabian Peninsula, especially the land adjacent to the Red Sea (including Hijaz) is one of the oldest landmasses on earth. This land is known as the Arabian-Nubian Shield. With an age of at least 600 million, the rocks in the Arabian-Nubian Shield have actually been so dense that they are much more stable than other younger landscapes.
Basic dyke cutting granite, Arabian-Nubian Shield.credit image
But in our Arab-Nubian Shield, we can witness the moment of birth of the new earth crust and the expansion of tectonic plates. The long stretch of the Red Sea that adorns the region is, in fact, a great deep valley that floods the salt water that flows from the Indian Ocean. This great valley is not an ordinary valley because it is formed by intense tectonic movement. It is joined with other straight valleys stretching from Turkey to Central Africa in an expression called the Great Rift Valley of about 4,000 kilometers. It is in some parts of the valley that the hot magma bursts from the sheaths, especially along the small cracks of the Red Sea base axis, especially on the south side. Once out, the hot magma begins to cool and freeze into a plate of oceanic tectonic plates. If such a pattern persists, then in the next tens of millions of years the Red Sea will thus expand into new oceans while the tiny fissures of its fundamental axis evolve into the central ridge of the ocean like Iceland today. So do not be surprised if this time in the middle of the Red Sea met a number of volcanoes. Some remain submerged beneath the surface of the water and some are poking over the sea as volcanic islands.
Harrat Rahat..credit image
But the cracks do not just appear at the bottom of the Red Sea. In the Hijaz region, a number of similar cracks formed and became a platform for similar hot-spot volcanism. In these cracks magma bursts out forming a typical Hijaz volcano. Do not imagine a beautiful cone-shaped Arab cone like the composite volcanoes (stratovolcano) in Indonesia. Hot-point volcanism produces a more dilute basaltic magma, so the Hijaz volcano is in fact just a pile of lava scattered over a very large area with a number of low-altitude scoria cones appearing in it. It can be said that the Hijaz volcano has a 'bad' panorama. But behind its 'ugliness', volcanism in the land of Hijaz is truly remarkable. Accumulatively in the last 10 million years, it has spewed basaltic lava covering an area of 180 thousand square kilometers, equivalent to one-tenth of the size of Indonesia.
One of the cracks here is that which stems from the holy city of Makkah al-Mukarramah and continuously to the north-northeast passes near the holy city of Madinah until it ends in Nafud. Therefore the crack along the 600 km is better known as the cracks of Makkah-Madinah-Nafud volcanic line. It is through this crack that magma overflows to the surface of the soil and forms at least four Hijaz volcanoes. From south to north, respectively are Harrat Rahat, Harrat Kurama, Harrat Khaybar and Harrat Ithnayn.
Harrat Khaybar حرة خيبر is located in Saudi Arabia.credit image
Rahat Harrat became the largest volcano on this crack path, even across the Arabian Peninsula. It stretches for 310 kilometers from Jeddah to Medina with an average width of about 75 kilometers. Rahat Harrat is basically a pile of basaltic lava that has been frozen with a total volume of 2,000 cubic kilometers. Lava as much as it gradually fired through 400 channels of magma and more than 2,000 scoria cones throughout the last 10 million years. Practically the holy city of Makkah and Medina actually stands right on the flood of a gigantic giant volcano that has another name Harrat Bani Abdullah, or Harrat Madinah, or Harrat Rashid, or Harrat Turrah, or Harrat el-Medina, or Harrat er-Raha, or Jabal Ma 'tan, or Jabal Umm Ruqubah, or Jabal al-Hurus, or Jibal Diba' Al Hurus this. And at the northern tip of this gigantic volcano, the Madinah eruption occurred within 7.5 centuries ago.
The eruption of Medina is not the end of Hijaz volcanic activity. These unique volcanoes continue to be active even today. In 2009 there was a sudden surge in the number of volcanic earthquakes in Harrat Lunayyir, a small Hijaz volcano located in the northwest of the holy city of Medina. During April to June 2009, there were 40,000 volcanic earthquake shocks with a magnitude between 2 and 5.4 on the Richter scale. This is a very clear sign that the basaltic magma in the bowels of the Hijaz region is still trying to find a way out to the surface. The sign is more clear through the formation of cracks along the 8 kilometers wide 45 centimeters. Learning from the experience of Madinah eruption 7.5 centuries ago, Saudi authorities did not waste time to evacuate about 30,000 people in the city of al-Ays in this volcano complex. But unlike Harrat Rahat, Harrat Lunayyir has never spewed magma. He failed to erupt. Maybe still waiting for another chance in the future. Thanks !!!
BEST REGARDS @irza