Anza is located near the San Jacinto Fault line. This is where many earthquakes rumble. Since the first homesteaders moved into the region, tremors with magnitudes as large as 7.0, have been observed. The local seismic stations are there to record these events.

At the University of California San Diego, the ANZA Seismic Network includes 17 three component broadband seismograph stations centered near Anza.

"We determine how big [an earthquake] is," said Frank Vernon, research seismologist for the UCSD Anza group, during a recent phone interview.

The ANZA Seismic Network is a subnet of the Southern California Seismic Network or SCSN – which has been monitoring earthquakes in the area since the 1920s.

The subnets were designed to trigger when a particular number of stations detected an event. This enables SCSN to regularly detect small events.

The digitally telemetered stations span the San Jacinto and Rose Canyon fault zones from the Buck Ridge fault in the south to the Hot Springs fault at the north end, according to the Broadband Seismic Data Collection Center’s Web site at www.eqinfo.ucsd.edu.

The network includes sites in Anza as well as the Cahuilla and Terwilliger areas. Each uses instruments that measure the motion of the ground. The stations were placed in this area to be closest to the fault line where the most activity occurs.

Equipment consists of seismometers – instruments that measure motions of the ground and trace and gauge the size of different sources – with digitizers which relay information to other stations.

The seismometer signals pass through filters, and will detect the ripples in space-time by using a device called a laser interferometer.

"[The stations] sit in remote areas by themselves, not bothering anyone, and then send the data back to us," said Vernon, who has been monitoringearthquake activity in the area for over 30 years. "We try to understand the tectonics as a whole."

Vernon will be giving a talk on his observations.

On April 16, he will speak on earthquakes along the San Jacinto Fault line, at the Anza Valley Library at Hamilton High School, beginning at 5:30 p.m.

In this presentation, the historical seismicity will be discussed along with what is known about the potential for future earthquakes.Current research directions on earthquakes in the Anza area will be explored.Vernon hopes attendees will participate in a question and answer session.

For additional information on this event, visit www.hamiltonmuseum.org or call (951) 763-1350.

On March 16, at 4:04 a.m., the Anza group recorded an earthquake (preliminary ml 4.4) located in the Greater Los Angeles area.

An earthquake (preliminary Mw 6.6) located in the New Ireland region, Papua New Guinea was recorded on March 20, at 7 a.m.

ANZA Seismic Network also recorded tremors (preliminary Mw 6.6) in the Andaman Islands, India region on March 30, at 9:54 a.m.

On March 31, at 2:20 a.m., they recorded an Advertisement

Primus Golf Academy earthquake (preliminary ml 4.1) in Baja California, Mexico.

And at 3:40 p.m., on Easter Sunday, the Anza group recorded the 7.2 magnitude earthquake which epicentered near Guadalupe Victoria, Baja California, Mexico.

Homes, businesses and high rise buildings throughout Riverside, Los Angeles and San Diego rocked back and forth but no injuries were reported.

The U.S. Geological Survey reported that the area has been rocking with magnitude 3.0 quakes all week.

The quake was felt strong in Riverside County and the Coachella Valley but no damage or injuries were reported, according to Matt Diaz, an investigator with the Riverside County Sheriff’s Department.

"I’m in the desert and I felt it pretty good, it was actually very strong," Diaz said.

The ground also shook in the Palm Springs area causing quite a jolt to residents, but no significant damage.

People at Desert Regional Medical Center got some rattled nerves but the building was undamaged, according to Palm Springs Fire Captain David Rees. Things were similar in Palm Desert.

"At the Westfield Palm Desert mall some items came off the shelves but it was pretty minor," said Palm Desert police Sgt. Charles Hoffman.

Firefighters across Riverside were out looking for damage after the quake hit but nothing was found, said Cal Fire’s Cheri Patterson.

Southern California spokeswoman Lauren Bartlett said no power outages were reported in Riverside County or in the Coachella Valley.

The quake was also felt in Arizona and Nevada, according to local reports.

Due to the activity’s extensive size, many ANZA Seismic Network stations, including Monument Peak – the closest station to the event, which was 80 miles away – had their waveforms clipped, according to the data center Internet site. A clipping is when a feeding signal overloads the equipment because it is too great for the unit to handle, leading to distorted recordings.

The Anza group takes all earthquake data, and uses it to learn more about the nature and environment of the land.

Ready for ‘The Big One?’

A University of Southern California earthquake education program manager will be giving a talk in Murrieta on April 19 at 6:30 p.m.

Dr. Robert de Groot will give a presentation with a special emphasis on faults and quakes in the western section of Riverside County.

His talk will include topics such as plate tectonics, "The Big One," and earthquake forecasts.

In addition, he will cover earthquake preparedness and how one should prepare, protect, and recover.

All attendees will receive a copy of "Putting Down Roots in Earthquake Country."

California is home to the largest annual earthquake drill in U.S. history – The Great California ShakeOut.

In 2010, the drill will be held on Oct. 21 at 10:21 a.m. Before attending the presentation, register for the fall event at www.ShakeOut.org.

The public meeting will be held at Murrieta Fire Station No.1, on the north side of Juniper Street between Washington and Adams.