Technical Announcements. Employees in the News. Emergency Management. Survey Manual. The collaborative work of scientists from the U. Clark Air Force Base that happened to be situated only 9 miles from the volcano. The program and its partners respond to volcanic unrest, build monitoring infrastructure, assess hazards and vulnerability, and improve understanding of eruptive processes and forecasting to prevent natural hazards, such as volcanic eruptions, from becoming human tragedies.
At Pinatubo, the volcanic unrest began April 2, , with a series of small steam explosions. In Manila, Dr. Punongbayan also called his friend, Dr. The seismic drum room was a maze of wires and cables; the daily drum roll of seismicity posted on the walls. With air assistance from the U. All efforts were focused on answering the questions — will Pinatubo erupt catastrophically, and when?
Volcanologists are first to admit that forecasting what a volcano will do next is a challenge. In late May, the number of seismic events under the volcano fluctuated from day-to-day. Trends in rate and character of seismicity, earthquake hypocenter locations, or other measured parameters were not conclusive in forecasting an eruption. A software program called RSAM real-time seismic amplitude measurement , developed in to keep an eye on Mount St.
Helens, helped scientists analyze seismic data to estimate the pent-up energy within Pinatubo that might indicate an imminent eruption. The map was based on the maximum known extent of each type of deposit from past eruptions and was intended to be a worst-case scenario. The map proved to forecast closely the areas that would be devastated on June The Clark Air Base sprawled over nearly 10, acres with its western end nestled in the lush, gently rolling foothills of the Zambales Mountains—only 9 miles 14 km east of Mount Pinatubo.
On the way back down, Pinatubo's ash mixed with Yunya's rain, creating a concretelike mud that collapsed roofs more than 9 miles 15 km away. The streets were choked with evacuees, including the scientists in charge of monitoring the volcano, who were reduced to rinsing their ash-streaked windshield with a six-pack of cherry soda.
The eruption of Mount Pinatubo was the second-largest volcanic cataclysm of the 20th century, second only to a eruption on the sparsely populated Alaskan Peninsula. Mount Pinatubo, on the other hand, threatened tens of thousands who lived on or near its slopes.
Nonetheless, only a few hundred people died in the initial eruption, thanks to round-the-clock volcano monitoring, proactive evacuation plans, and a little bit of luck. It was a success that helped cement the importance of close volcano-watching — though scientists are still searching for the unique clues that might warn them that an eruption will be as large as Pinatubo's.
The first sign that Pinatubo might be restless came in mid-March Frequent earthquakes shook the area, alarming residents. On April 2, an explosion opened a line of steaming vents along the mountain. Pinatubo had not emitted so much as a volcanic burp in living memory, but a look at the area's geology revealed that the mountain could produce very large eruptions , said USGS team leader Chris Newhall, now the volcano group leader at the Earth Observatory of Singapore.
Instead, the team gathered every bit of information they could about the mountain. They deployed additional seismometers, walked around looking at ancient volcanic deposits and flew helicopter missions close to the volcano to see what was going on. No geologic map, no hazards map, nothing. On top of the scientific challenge, there was also a massive amount of personal pressure.
Mount Pinatubo is part of a chain of composite volcanoes along the Luzon arc on the west coast of the island area map. The arc of volcanoes is due to the subduction of the Manila trench to the west. The volcano experienced major eruptions approximately , , and years ago. The events of the Mount Pinatubo eruption began in July , when a magnitude 7.
In mid-March , villagers around Mount Pinatubo began feeling earthquakes and vulcanologists began to study the mountain. Approximately 30, people lived on the flanks of the volcano prior to the disaster. On April 2, small explosions from vents dusted local villages with ash. The first evacuations of 5, people were ordered later that month.
Earthquakes and explosions continued. On June 5, a Level 3 alert was issued for two weeks due to the possibility of a major eruption. The extrusion of a lava dome on June 7 led to the issuance of a Level 5 alert on June 9, indicating an eruption in progress. An evacuation area 20 kilometers The 18, personnel and their families were transported to Subic Bay Naval Station and most were returned to the United States.
On June 12, the danger radius was extended to 30 kilometers On June 15, the eruption of Mount Pinatubo began at p. The eruption lasted for nine hours and caused numerous large earthquakes due to the collapse of the summit of Mount Pinatubo and the creation of a caldera. The caldera reduced the peak from meters feet to meters feet high is 2. Unfortunately, at the time of the eruption Tropical Storm Yunya was passing 75 km 47 miles to the northeast of Mount Pinatubo, causing a large amount of rainfall in the region.
The ash that was ejected from the volcano mixed with the water vapor in the air to cause a rainfall of tephra that fell across almost the entire island of Luzon. There were no known historic eruptions. Before the eruption in Pinatubo was m high ca. Pinatubo mostly noted for a failed geothermal development project. Eruptions of Mount Pinatubo Pinatubo has had at least 6 periods of activity with large explosive eruptions in its past 35, years prior to the eruption. The eruption in this context actually ranks as one of the smaller eruptions.
An eruption, which occurred 35, years ago and probably created the caldera, was likely much bigger. Show interactive Map. Last earthquakes nearby.
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