YES, YOU FELT IT! - Thank you for reporting earthquakes online

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Before the ink was thoroughly dry on the "Did You Feel It" Volcano Watch posted two weeks ago, a magnitude-3.7 earthquake occurred and put the described process to a test. Thanks to all our faithful reporters, DYFI passed with flying colors! Intensity colors, to be exact.

YES, YOU FELT IT! - Thank you for reporting earthquakes online...

Community Internet Intensity Map (CIIM) for Kiholo Bay earthquake, September 4, 2006.

(Public domain.)

The "Did You Feel It?" Web site was quickly flooded with contributions to the compilation of the Community Internet Intensity Map (CIIM). The earthquake struck on August 28, at 8:10 p.m. H.s.t (Hawaiian Standard Time), between O`ahu and Moloka`i. As the online reports came in, they were automatically tabulated and intensity values assigned. A resulting CIIM was generated, displaying color-coded intensity values for the zip codes of reporting locations. The "Did You Feel It?" Web site has received nearly 1,100 reports for this earthquake.

A magnitude-3.7 event closer to our Big Island home occurred this past week, on September 4th at 5:27 p.m. H.s.t., beneath north Kona. There were 82 responses, mostly from the west side of the island. All told, the maximum Modified Mercalli Intensity was III. Because the earthquake was larger than 3.5, an initial CIIM was automatically created. The map was updated as reports came in, resulting in changed assigned intensity values, if warranted. For your interest, associated statistics and other fascinating information are just a "click" away.

The U.S. Geological Survey's Hawaiian Volcano Observatory (HVO) continues to maintain the "Recent Earthquakes in Hawai`i" Web page, which includes earthquake maps and lists. Information about the earthquake you just felt is still available, with the familiar earthquake location details. Once posted, that information will be online for 14 days.

Depending on the earthquake, other seismic monitoring and reporting groups, in addition to HVO, will compute locations and magnitudes. Discrepancies among the calculations will occur when different collections of data or earthquake-data-processing tools are used. This was the case for the O`ahu earthquake that occurred on August 28. To avoid confusion in reporting, the various groups must work closely and coordinate their efforts according to agreed-upon standards.

We extend USGS and HVO appreciation to those who continue to be island- and state-wide reporters. Only with your support are we able to include information which helps makes our data collection more comprehensive. Please remember, when answering a "Did You Feel It?" questionnaire, to correctly select the event of interest from the list. If the date and time of the earthquake that you felt are not yet posted, select "unknown earthquake form" or "New Earthquake?" to ensure that your report is credited to the proper event. The "Did You Feel It?" computer tools will sort it out. Mahalo to all.

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Volcano Activity Update

This past week, activity levels at the summit of Kīlauea Volcano have remained at background levels. The number of earthquakes located in the summit area is low (usually less than 10 per day that are large enough to locate). Earthquakes have been clustering south of Halema`uma`u and near Poliokeawe. Widening of the summit caldera, indicating inflation, has resumed after pausing earlier in April. The eighth deflation-inflation tilt event occurred on August 28.

Eruptive activity at Pu`u `O`o continues. On clear nights, glow is visible from several vents within the crater. There have been several gas-pistoning events within the Drainhole vent in the Pu`u `O`o crater. Lava continues to flow through the PKK lava tube from its source on the flank of Pu`u `O`o to the ocean at East Lae`apuki. Lava also flows through a branch of this tube to the east, called the Campout flow, to the ocean at East Ka`ili`ili. Both locations where lava is entering the ocean are within Hawai`i Volcanoes National Park.

Access to the sea cliff near the ocean entries is closed, due to significant hazards. The National Park has reopened the surrounding area, however. If you visit the eruption site, check with the rangers for current updates, and remember to carry lots of water when venturing out onto the flow field.

There were three earthquakes beneath Hawai`i Island reported felt within the past week. A magnitude-2.8 earthquake occurred at 10:46 a.m. H.s.t. on Thursday, August 31, and was located 1 km (1 mile) northeast of Pu`ulena Crater (Puna) at a depth of 4 km (2 miles). A magnitude-3.2 earthquake occurred later that same day at 8:39 p.m. and was located 6 km (4 miles) northwest of Pa`auilo at a depth of 6 km (4 miles). A magnitude-3.7 earthquake, discussed above, occurred at 5:28 p.m. H.s.t. on Monday, September 4, and was located near Kiholo Bay at a depth of 42 km (26 miles).

Mauna Loa is not erupting. During the past week, earthquake activity remained low beneath the volcano's summit (three earthquakes were located). Extension of distances between locations spanning the summit, indicating inflation, continues at slow rates.