Dr.Athiqul H.Laskar Earthquakes have been a frequent phenomenon in the Northeast, in the past. The Northeastern states are not only known for their enthralling scenic beauty or a typical close proximity between them, but also, for their susceptibility to high intensity earthquakes. This region has been subjected to 18 major earthquakes (M>7) in the past hundred years or so. One notable earthquake that brought about widespread damage and destruction hit Shillong in 1897. It had a magnitude of 8.7. There were 1542 casualties. All concrete constructions were totally shattered. Several vents and fissures developed and there were some secondary after-effects including rotation of pillars, sinking of houses, rising of river height and crushing of soils. Mandalgiri, Chidrang and Samin faults plus the Bordwar fracture are the ground ruptures that resulted because of this earthquake. Another major earthquake of the region was the Cachar Earthquake that occurred on 10th January in the year 1869. Several concrete structures and buildings located at Imphal, Nowgang and Silchar were completely destroyed and there were four casualties in Imphal. Fissures developed in surma, Barak and Manipur Valleys. It had a magnitude of 7.8 and focus was 50km deep. A devastating earthquake to rock the Northeast region was the Dhubri Earthquake that occurred in 1930 with a magnitude of 7.1. It brought about widespread devastation across western Assam, northern Bengal and northern Bangladesh. Most of the buildings developed cracks and some of them collapsed partially. Many injuries were reported. The Assam Earthquake that occurred in the year 1950 brought about widespread destruction in the entire region of Upper Assam and Mishmi Hills and Abor Hills of Arunachal Pradesh. It had a focal depth of 29 km. 1520 people were reported to be dead and almost half the wildlife was killed. Several buildings, roads, bridges and railway tracks were damaged. Ground cracks and fissures developed and there were flash floods and landslides. The Cachar Earthquake that was recorded in1984 had a magnitude of 5.8 and a focal depth of 33 km. There were about 20 casualties. Buildings, bridges and roads were damaged. Cracks and fissures appeared. Earthquakes are caused by the movements that occur along the faults, resulting from tectonic and geological processes. The high intensity of seismic activity in the Northeast region of India is owing to the collision of tectonic plates along Eurasian plate and Indian plate in the north and movements in the tectonic plates along Indo-Myanmar range in the east. The Northeastern region has been divided into five distinct seismic-tectonic zones. This division depends on distribution of epicenters, geotectonic features and fault plane solutions. The identified earthquake-prone zones in the North-East lie in the Eastern Himalayas, the subduction zone in the Indo-Myanmar region, the Syntaxis zone in the Himalayan and Burmese arcs, Fold belt of Bengal, Mizoram and Tripura as well as plate boundary zone of the Assam Valley and Shillong Plateau zone. The seismicity in the Eastern Himalayas is because of the tectonic collision between the Eurasian plate and the Indian plate. Seismicity is said to be sparse in this zone and only two earthquakes of reasonable intensity has so far been recorded in this zone. The subduction zone in the Indo-Myanmar region seems elongated and it takes the shape of crescent. This is an active seismic zone and it has witnessed as many as ten earthquakes of major intensity during the last one hundred years. Syntaxis Zone is supposed to be definitely more active than the Himalayan Collision Zone and has experienced the Great Assam Earthquake that took place in the year 1950 (M=8.7) and is believed to be caused by strike slip movement all along Po Chu fault. It is a known fact that seismicity in this zone is basically because of tectonic collision between Eurasian Plate and Indian Plate. There is major seismic activity in the Shillong Plateau and it has experienced the devastating Shillong Earthquake in the year 1897. The Assam Valley however, has witnessed less seismic activity in the past, but the well known Assam Gap (the area that lies in between the syntaxis and the plateau) may be hit by large earthquakes in future. There is past evidence of low seismic activity in the Bengal basin whereas the Tripura folded belt experiences quite moderate activity. Northeast is vulnerable to seismic activity not only because it is in the earthquake prone belt but also because of other factors. It has undergone remarkable rise in population density and also, there has been an incredible increase in the developmental programs. There has been an overpowering growth of unplanned and thoughtless urban centers during the past two decades. This definitely has intensified the vulnerability to earthquakes. The high vulnerability to earthquakes in the North East necessitates that all new buildings, amenities, assets and public infra-structure developing in this region will definitely have to strictly adhere to the provisions listed by the National Building Code of the year 2005, safety codes and other earthquake-related codes. The officials in charge of examining building plans and those that are authorized to grant building permissions must have a thorough knowledge of the existing codes and standards that need to be strictly followed, while constructing structures in extremely high risk zones. Bank loans for the construction of buildings should be granted only when a compliance certificate is issued by a competent authority. A structural engineer should approve of the design and make sure that all required earthquake-resistant features have been complied with. Quite a few existing buildings may have been built by masons and private builders who could be lacking in necessary technical expertise and skills required to build earthquake-resistant buildings. It is quite natural that inadequate attention was given to the structural safety and security of the buildings to resist the high or extremely high intensity earthquakes. The district administration needs to identify public assets and lifeline infrastructure and assess the structural safety of the structures by hiring well qualified and expert technical personnel. National Disaster Management Authority (NDMA) has suggested the selective retrofitting of some selected district hospitals in the North Eastern states as well as some selected schools from certain chosen districts located in the seismic zones IV and V in the North Eastern states. Predicting earthquakes is not an easy task and involves taking into consideration factors like place, time and magnitudes of the earthquakes that would occur in future. Some of the basic tenets of earthquake prediction are: • Earthquakes of lower intensity are more frequent than major earthquakes. • The areas previously hit by earthquakes are more likely to be affected again. • Earthquakes of high intensity are usually followed by aftershocks and insignificant earthquakes. • The future earthquakes may have same magnitude as that of the previous earthquakes. • Tectonic history, geological data and the incidence of an earthquake are all co-related. Though based on these principles precise prediction of earthquakes is not possible there have been attempts of earthquake prediction in the Northeast. Prominent researchers like Weiss and Khattri are expecting a significant earthquake in the Assam Gap. While Guha and Bhattacharyya believe that the Cachar Earthquake that occurred during the year 1984 marks the beginning of an active period from seismological point of view. Most studies carried out by researchers have suggested that there is a likelihood of a major earthquake in the Northeast in future (Feedback: www.conantinstitute.org.in.).