August 29, 1997

A weekly feature provided by scientists at the Hawaiian Volcano Observatory.

Earthquake network serves volcano and tsunami warning

For over a decade, we have watched lava flows from Kilauea overrun nearly 40 square miles of land, destroying precious forests, communities, and sacred ground. At other times, major earthquakes have generated damage over considerable parts of the island of Hawaii and, in the cases of the 1871 and 1938 earthquakes, even other islands. And although many current Hawaiian residents have never experienced one, tsunami or giant sea waves originating thousands of miles away have inundated coastal areas in the state and resulted in destruction of property, injury, and loss of many lives.

The Hawaiian Volcano Observatory (HVO) was established to conduct research and monitor the island's active volcanoes for the purpose of mitigating hazards posed by eruptions. As technology advances, we continue to develop and upgrade our monitoring systems in order to better understand volcanoes and assess the hazards they pose. Some of our results are applicable to other hazards, such as tsunami.

A collaborative project is underway to better detect and identify earthquakes occurring anywhere in the Pacific region--especially those that generate tsunami. With funding provided by the National Oceanic and Atmospheric Administration (NOAA), the USGS is upgrading seismic instruments and computer processing systems in Alaska, the Pacific Northwest, northern California, and Hawaii. The goal is to provide seismic data and information rapidly to the NOAA tsunami warning centers in Alaska and Ewa Beach, Hawaii.

As part of the project, HVO is upgrading some field stations. Also, we are installing new computer systems for improved automated data analysis and information distribution to the NOAA Pacific Tsunami Warning Center.

The benefits of the seismic upgrade go beyond tsunami warning applications. The upgraded computer systems will allow more rapid processing of seismic data in general, so that the many volcanic and tectonic earthquakes occurring in Hawaii will be more precisely characterized. The upgraded field stations will provide a greater earthquake recording range than our current instruments do, so we will obtain better records. The improved records offer a more complete view of the energy released during an earthquake, and these data will enhance our ability to study the physical processes related to Hawaiian earthquakes and volcanoes.

The main purpose of the upgrade is to improve our ability to record significant earthquakes and rapidly distribute the vital information to those who require it for tsunami warning. A secondary benefit is to improve our volcanic and seismic hazards assessment capabilities.

Kilauea Eruption Status--August 29, 1997

In the past 10 days, Kilauea's east rift zone eruption has settled into a regular pattern. Lava issues almost constantly from the cone inside Pu`u `O`o crater, flows a short distance, and disappears through cracks in the crater floor. It is visible again in tubes south of Pu`u `O`o, through which it travels to the coast. Eruption rates range from 100,000 to 900,000 cubic meters per day (as much as 1.2 million cubic yards per day). Lava enters the sea at Waha`ula and 1 km (0.6 mi) west near Kamokuna.

Recent Big Island Earthquakes

There were no felt earthquakes reported during the week.