Following the explosive phase is the subaerial stage which primarily consists of the “shield” shape forming and landslides. Following the shield stage is the post shield stage. In this stage, the type of lava changes and eruptions become more explosive. The new lava flows increase the slope and eruption rate gradually decrease over a period of 250,000 years. As the volcano becomes dormant, the erosional stage takes place.
In 1980, Mt. St. Helens in Washington state erupted, leaving ash everywhere; demolishing and exterminating all plant life. These Geo processes can cause land to rise or sink. One epitome of these are the islands of Hawaii. Hawaii was molded from underwater volcanoes.
Subduction is the process when in which one tectonic plate moves under the other, sinking into the mantle as the plates converge. Regions where subduction takes place are known as subduction zones. Subduction zones tend to have very high rates of earthquakes, volcanism, and mountain building. Some examples of volcanoes that are located above subduction zones would be Mount St. Helens, Mount Etna, and Mount Fuji. Furthermore, the strains, which are a result of plate convergence, are known to be the cause of at least three different types of earthquakes.
00Earthquakes occur almost daily due to the fact that Costa Rica lies between two tectonic plates: the Carribean plate and the Coicos plate. These two plates push and shove each other causing small tremors throughout which can cause landslides,volcanic eruptions and once in a couple years, quakes with devastating results. The strongest earthquake recorded occurred in 1991 with a measure of 7.6 on the Richter scale. This earthquake left 4 dead and buildings as well as bridges and road were completely destroyed. If another Earthquake occurs, the coastal cities would be the most affected ones as they are closer to the plates.
Convection Currents The Alaskan Way Viaduct will collapse if an earthquake happens. Tectonic plates rubbing together causes an earthquake. What causes them to rub together? An earthquake happens through a sequence of cause and effect. Altogether, temperature, density, and convection currents work together to cause an earthquake.
On May the 18th 1980, Mt Saint Helens in Washington State, United States of America erupted covering surrounding areas in ash, mud, toxic gases and lava. Mt Saint Helens is one of many active volcanos in the Cascade Mountain Range that runs along the Pacific Coast of the United States of America, a part of the Pacific Ring of Fire, named due to the many active tectonic plates in the region. The blast devastated an area of 20 square km. Within 10km of the summit, were there had previously been dense forest, no trees remained, beyond this area all trees were blown down. A further 600km2 was covered in ash and debris.
Nevado del Ruiz Case Study The Eruption and its Impacts What happened? On November 13th, 1985, the Nevado del Ruiz volcano erupted triggering destructive lahars, which caused approximately 23 000 human deaths, 4500 were injured and, following the catastrophe, 8000 became homeless . Signs of seismic activity can be traced back to July of the same year, where seismograph on the mountain showed uncharacteristically seismic activity levels . Later, in September 1985, not only had the level of seismic activity increased in the region, but steam explosions accompanied them . In November, seismic activity was observed near the summit of the volcano .
Supervolcanoes are even more powerful than regular volcanoes. This explosion is so powerful that it will destroy most of the northern United States. It would also launch one thousand cubic kilometers (six hundred twenty one cubic miles) of ash into the sky. This is the equivalent of four
This is important to understand so that we may respect the power and destruction of volcanoes. Powerful civilizations have fallen because of volcanic eruptions and the entire world can be impacted because of a single eruption. Volcanoes can erupt with more power then any human made bomb and can send an array of dangerous hazards down its slopes. It is ironic that mankind knows all of the risks that come with living by a volcano, not only because of scientific research but also because of past volcanic eruptions, and yet people continue to build houses near or next to volcanoes. Volcanoes offer a lot of benefits to society.