Nicaragua boosted its responses to volcanic activity in the northwestern region Saturday, as the San Cristobal volcano acted up for the second time in a week.

Authorities installed 43 radio communication stations along the Pacific coast to monitor San Cristobal and another volcano, Telica.

The radio posts aim to "ensure improved monitoring of seismic and volcanic behavior in the area," said civil defense chief Colonel Nestor Solis, enabling authorities to issue more accurate warnings sooner.

A number of towns near San Cristobal, located some 135 kilometers (83 miles) northwest of the capital, were evacuated last week after the volcano began rumbling, sending a column of smoke and ash high into the sky, before subsiding.

On Saturday, the 1,745-meter (5,725-foot) tall volcano again spewed "abundant gas emissions moving toward the northeast" and increased seismic tremor and sulfur concentrations, according to the Nicaraguan Institute of Territorial Studies, or INETER.

Sulfur dioxide monitoring showed levels of the compound -- considered a measure of volcanic activity -- were nearly double the readings from previous days, said the director of national disaster prevention and relief agency SINAPRED, Guillermo Gonzalez.

Last week's explosion caused "fractures on the southern wall of the volcano" and "blockages preventing gas from passing out of three of five vents situated on the south wall of the internal crater," according to Nicaraguan and Salvadoran experts who visited the site.

San Cristobal, the tallest of Nicaragua's seven active volcanoes, is believed to have erupted for the first time in 1685.