# Volcano Watch - Kīlauea and Masaya celebrate secrets of "sisterhood"

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Many of us are aware of the "sister city" program, in which two cities form a relationship to promote understanding, cultural and educational exchange, and visitor development activities. The town of Hilo, Hawai'i has several sister cities, including one in Chile, and a few in Japan.

If there were a sibling volcano program, it seems that one likely candidate for Kīlauea's hanai (adopted) sister would be the Central American volcano Masaya, located in Nicaragua. Masaya Volcano was the site of a recent international workshop where scientists came together to compare measurement techniques for studying volcanic gases. Since gases are the driving force behind eruptions, their study is important for understanding and keeping track of volcanic activity. Although volcanic gases are the frequent brunt of off-color jokes, they are also important for examining the effects of volcanoes on the earth's atmosphere, both globally and locally.

Volcano scientists from Hawai'i who participated in the workshop encountered features that cause Kīlauea and Masaya to seem familial, for instance, their physical settings. Both Kīlauea and Masaya are "drive-in" volcanoes with a well-kept road and parking lot at their summits. The easy access entices large numbers of visitors each year, who peer into impressive summit craters. Both volcanoes are located in national parks, and the high visitation creates challenges for park managers, who are responsible for ensuring visitor safety. The last major visitor injury in the summit area of Kīlauea was in 2000, when a visitor ignored posted warnings and was burned after slipping and falling into a steam vent at Sulphur Bank. In 2001 a small "throat-clearing" event at Masaya's Santiago crater showered visitors and their cars with volcanic debris, injuring some people. The ease of accessibility and recent activity also make both volcanoes highly popular with scientists, who test new instrumentation and techniques.

A visitor hiking around these two volcanoes would notice some comparable structures and eruptive products. Masaya's Nindiri Crater and Kīlauea Iki Crater are similar, as both contain lava lakes which have cooled and subsided in their respective volcano's summit areas. Also, since both volcanoes have a history of explosive activity, sometimes stemming from water-magma interaction, layers of fine deposits can be seen in areas of both volcanoes. Pele's hair and tephra are easy to find in the two locations, as are basaltic lava flows.

Another common feature is that both Masaya and Kīlauea emit significant amounts of sulfur dioxide gas. Over the past decade, Masaya has released an average of about 300 to 2,500 tons of sulfur dioxide gas each day, with brief periods of even higher emissions. Kīlauea has yielded similar emission rates over the same period. This gas causes a number of environmental problems which are easily observed downwind of the volcanoes. These include accelerated rusting of metals, leaching of lead and other metals into water catchment systems, and damage to vegetation.

At Masaya, under prevailing winds, the plume affects downwind communities for some 45 km (28 miles) before being blown out to sea, with a number of communities within 10 km (6 miles) of the emission source. These Nicaraguan communities are heavily impacted by sulfur dioxide gas on a daily basis, and, as in sister communities on the island of Hawai'i, both short- and long- term public health hazards are a concern. Health professionals and physical scientists are working together to better understand effects of emissions on downwind areas for both Kīlauea and Masaya.

Although Masaya and Kīlauea are separated by more than 7,500 km (4,700 miles), they share attributes that have encouraged information and educational exchange and development of safe visitor activities, showing a healthy "sister volcano" relationship. And as visitors to these volcanoes are quick to note, in this case, sisterhood is breathtakingly beautiful.

### Volcano Activity Update

Eruptive activity at the Puu Oo vent of Kīlauea Volcano continued unabated during the past week. Streams of lava are still visible on Pulama pali and Paliuli. The lava breaks out of the main Mother's Day tube above Pulama pali and wends it way to the coastal flat in a series of open channels and tubes. Surface flows extend from the base of Paliuli to the coast at Highcastle, where the small ocean entry that began on May 19 remains active. The black sand beach at Highcastle has been covered with lava, and a tiny delta is building seaward from the buried beach.

The public is reminded that the ocean entry areas are extremely hazardous, with explosions accompanying sudden collapses of the new land. The steam clouds are highly acidic and laced with glass particles. The National Park Service has put warning signs in critical places. Do not venture beyond these signs and onto the lava deltas and benches.

Four earthquakes were felt on the island between May 22 and May 28. A small, magnitude-1.5 earthquake took place at 11:14 a.m. on May 22 and was felt by a Papaaloa resident. It was located 3 km (2 miles) southeast of Ookala at a depth of about 22 km (14 miles). An earthquake of magnitude-3.9, the largest of the week, occurred at 07:35 on May 24 and was felt across much of the island. It was located 10 km (6 miles) west-northwest of Ka`ena Point at a depth of 10 km (6 miles). Only 14 minutes later, a magnitude-2.9 earthquake came from the same location and depth; it was felt in Glenwood. Kona did not escape hosting a felt earthquake; at 07:30 on May 25, one of magnitude 2.2 came from a depth of 16 km (10 miles) about 7 km (4 miles) south of the summit of Hualalai and was reported by a resident of Kealakekua.

Mauna Loa is not erupting. The summit region continues to inflate slowly. Seismic activity remains low, with no earthquake located in the summit area during the last seven days.