Assam Earthquake Today: An earthquake with a magnitude of 6.4 on the Richter Scale hit Sonitpur, Assam today at 7:51 AM: National Center for Seismology
An earthquake measuring 6.4 on the Richter Scale hit Assam on Wednesday. According to the National Center for Seismology, the epicenter of the quake was Sonitpur and the quake occurred at 7.51 am at a depth of 17 kilometres.
According to the National Centre of Seismology, the earthquake measuring 6.4 on the Richter Scale originated in Sonitpur, Tezpur of Assam. The first earthquake was recorded at 7:51 am and according to the seismology centre, it was centred 43 km west of Tezpur in Assam.
There were two aftershocks following the first major earthquake, one around 7:55 am and another a few minutes after that. The two aftershocks measured 4.3 and 4.4 on the Richter Scale.
This is the first visual of the after-effects of the massive Earthquake in Assam.
Locals in Assam and North Bengal reported the major earthquake around 8 am on Thursday. Assam minister Himanta Biswa Sarma was among those who tweeted about the earthquake.
Assam CM Sarbananda Sonowal said, "Big earthquake hits Assam. I pray for the well being of all and urge everyone to stay alert. Taking updates from all districts."
Locals in Assam and North Bengal who experience the tremors said the earthquake may have lasted for at least 30 second and continued to shake up buildings during that time.
The earthquake hit 43km west of Tezpur area of Assam at 7.51 am on Wednesday, and had a depth of 17km, the National Center for Seismology confirmed. Strong tremors could also be felt in many other states of northeast, including areas of North Bengal.
"Earthquake of Magnitude:6.4, Occurred on 28-04-2021, 07:51:25 IST, Lat: 26.69 & Long: 92.36, Depth: 17 Km ,Location: 43km W of Tezpur, Assam, India," a tweet by the National Center for Seismology confirmed.
Not all earthquakes occur on plate boundaries, however: the destructive Killari earthquake in India in 1993 occurred within a stable cratonic area. The immensely destructive Lisbon earthquake of 1755 was also nowhere near a plate boundary.
I Introduction and Historical Background Earthquakes have been studied since the time of Aristotle, although their relation to geology and tectonic processes was not properly understood then.
Observers reported ground cracks and fissures that they related to a recent earthquake, even without an understanding of faulting. In 1493, Esfezari reported in Iran that the January 10, 1493,
Nauzad earthquake had fissured the ground “to such a depth that the bottom of the fissures was invisible ….” Déodat Gratet de Dolomieu, following a series of disastrous earthquakes in Calabria, Italy, in 1783, conducted a field survey in the area of maximum damage, describing a scarp (fente) that he believed had moved during the earthquake. (Later investigators determined that the scarp Dolomieu described was secondary to the subsurface fault that generated the earthquakes.) Johann F. J. Schmidt, an astronomer, described a “crack … eight feet high and six feet wide” that appeared on the south coast of the Gulf of Corinth in Greece after an earthquake at the city of Egion in 1861. Schmidt, as well as the earlier observers, may have considered such features as landslides rather than faults. A famous quote from Zechariah, who lived about 520 B.C. — “the mount of Olives shall cleave … toward the east and toward the west”—probably described a landslide, although the landslide may have accompanied an earthquake in 759 B.C.
Earthquake Seismology A. Nur, in Treatise on Geophysics, 2007 4.20.1.1 Frequency–Magnitude Relation and the Historical Observation Window Earthquakes recur. One of the fundamental observations of modern earthquake science is that earthquakes occur on faults, and that the seismicity on any fault follows a pattern of recurrence over time, called the frequency–magnitude relation. If we sort the many small earthquakes recorded by seismographs for a given fault, including ones too small to be felt without sensitive instruments, we see a pattern emerge. There are many more small quakes than large ones. In fact, a magnitude-3 earthquake is 10 times more likely to occur than a magnitude 4, which is 10 times more likely than a 5, and so on. At first glance, this seems to imply that very large earthquakes do not occur. On the contrary, the distribution actually gives us a specific empirical relationship between earthquake magnitude and recurrence interval on a particular fault, for all quake magnitudes, up to the largest that can occur on that fault. This relationship is called the frequency–magnitude relation. If 10 magnitude-6 quakes occurred in 100 years of recorded seismicity, and one magnitude 7 occurred, we would expect 0.1 magnitude-8 quakes to occur in that same period, provided that the fault is long enough to generate an earthquake that large. In other words, one magnitude-8 earthquake should occur every 1000 years or so. It is not surprising that we have not caught one of these large quakes on our instruments, since we have only been using them for 1/10 of that time interval. However, a city that has stood near that fault for 3000 years should have experienced three such large events during that time, along with many smaller events.
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